| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * mm/percpu.c - percpu memory allocator |
| * |
| * Copyright (C) 2009 SUSE Linux Products GmbH |
| * Copyright (C) 2009 Tejun Heo <tj@kernel.org> |
| * |
| * Copyright (C) 2017 Facebook Inc. |
| * Copyright (C) 2017 Dennis Zhou <dennis@kernel.org> |
| * |
| * The percpu allocator handles both static and dynamic areas. Percpu |
| * areas are allocated in chunks which are divided into units. There is |
| * a 1-to-1 mapping for units to possible cpus. These units are grouped |
| * based on NUMA properties of the machine. |
| * |
| * c0 c1 c2 |
| * ------------------- ------------------- ------------ |
| * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u |
| * ------------------- ...... ------------------- .... ------------ |
| * |
| * Allocation is done by offsets into a unit's address space. Ie., an |
| * area of 512 bytes at 6k in c1 occupies 512 bytes at 6k in c1:u0, |
| * c1:u1, c1:u2, etc. On NUMA machines, the mapping may be non-linear |
| * and even sparse. Access is handled by configuring percpu base |
| * registers according to the cpu to unit mappings and offsetting the |
| * base address using pcpu_unit_size. |
| * |
| * There is special consideration for the first chunk which must handle |
| * the static percpu variables in the kernel image as allocation services |
| * are not online yet. In short, the first chunk is structured like so: |
| * |
| * <Static | [Reserved] | Dynamic> |
| * |
| * The static data is copied from the original section managed by the |
| * linker. The reserved section, if non-zero, primarily manages static |
| * percpu variables from kernel modules. Finally, the dynamic section |
| * takes care of normal allocations. |
| * |
| * The allocator organizes chunks into lists according to free size and |
| * memcg-awareness. To make a percpu allocation memcg-aware the __GFP_ACCOUNT |
| * flag should be passed. All memcg-aware allocations are sharing one set |
| * of chunks and all unaccounted allocations and allocations performed |
| * by processes belonging to the root memory cgroup are using the second set. |
| * |
| * The allocator tries to allocate from the fullest chunk first. Each chunk |
| * is managed by a bitmap with metadata blocks. The allocation map is updated |
| * on every allocation and free to reflect the current state while the boundary |
| * map is only updated on allocation. Each metadata block contains |
| * information to help mitigate the need to iterate over large portions |
| * of the bitmap. The reverse mapping from page to chunk is stored in |
| * the page's index. Lastly, units are lazily backed and grow in unison. |
| * |
| * There is a unique conversion that goes on here between bytes and bits. |
| * Each bit represents a fragment of size PCPU_MIN_ALLOC_SIZE. The chunk |
| * tracks the number of pages it is responsible for in nr_pages. Helper |
| * functions are used to convert from between the bytes, bits, and blocks. |
| * All hints are managed in bits unless explicitly stated. |
| * |
| * To use this allocator, arch code should do the following: |
| * |
| * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate |
| * regular address to percpu pointer and back if they need to be |
| * different from the default |
| * |
| * - use pcpu_setup_first_chunk() during percpu area initialization to |
| * setup the first chunk containing the kernel static percpu area |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/bitmap.h> |
| #include <linux/cpumask.h> |
| #include <linux/memblock.h> |
| #include <linux/err.h> |
| #include <linux/lcm.h> |
| #include <linux/list.h> |
| #include <linux/log2.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/percpu.h> |
| #include <linux/pfn.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/vmalloc.h> |
| #include <linux/workqueue.h> |
| #include <linux/kmemleak.h> |
| #include <linux/sched.h> |
| #include <linux/sched/mm.h> |
| #include <linux/memcontrol.h> |
| |
| #include <asm/cacheflush.h> |
| #include <asm/sections.h> |
| #include <asm/tlbflush.h> |
| #include <asm/io.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/percpu.h> |
| |
| #include "percpu-internal.h" |
| |
| /* |
| * The slots are sorted by the size of the biggest continuous free area. |
| * 1-31 bytes share the same slot. |
| */ |
| #define PCPU_SLOT_BASE_SHIFT 5 |
| /* chunks in slots below this are subject to being sidelined on failed alloc */ |
| #define PCPU_SLOT_FAIL_THRESHOLD 3 |
| |
| #define PCPU_EMPTY_POP_PAGES_LOW 2 |
| #define PCPU_EMPTY_POP_PAGES_HIGH 4 |
| |
| #ifdef CONFIG_SMP |
| /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */ |
| #ifndef __addr_to_pcpu_ptr |
| #define __addr_to_pcpu_ptr(addr) \ |
| (void __percpu *)((unsigned long)(addr) - \ |
| (unsigned long)pcpu_base_addr + \ |
| (unsigned long)__per_cpu_start) |
| #endif |
| #ifndef __pcpu_ptr_to_addr |
| #define __pcpu_ptr_to_addr(ptr) \ |
| (void __force *)((unsigned long)(ptr) + \ |
| (unsigned long)pcpu_base_addr - \ |
| (unsigned long)__per_cpu_start) |
| #endif |
| #else /* CONFIG_SMP */ |
| /* on UP, it's always identity mapped */ |
| #define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr) |
| #define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr) |
| #endif /* CONFIG_SMP */ |
| |
| static int pcpu_unit_pages __ro_after_init; |
| static int pcpu_unit_size __ro_after_init; |
| static int pcpu_nr_units __ro_after_init; |
| static int pcpu_atom_size __ro_after_init; |
| int pcpu_nr_slots __ro_after_init; |
| static int pcpu_free_slot __ro_after_init; |
| int pcpu_sidelined_slot __ro_after_init; |
| int pcpu_to_depopulate_slot __ro_after_init; |
| static size_t pcpu_chunk_struct_size __ro_after_init; |
| |
| /* cpus with the lowest and highest unit addresses */ |
| static unsigned int pcpu_low_unit_cpu __ro_after_init; |
| static unsigned int pcpu_high_unit_cpu __ro_after_init; |
| |
| /* the address of the first chunk which starts with the kernel static area */ |
| void *pcpu_base_addr __ro_after_init; |
| |
| static const int *pcpu_unit_map __ro_after_init; /* cpu -> unit */ |
| const unsigned long *pcpu_unit_offsets __ro_after_init; /* cpu -> unit offset */ |
| |
| /* group information, used for vm allocation */ |
| static int pcpu_nr_groups __ro_after_init; |
| static const unsigned long *pcpu_group_offsets __ro_after_init; |
| static const size_t *pcpu_group_sizes __ro_after_init; |
| |
| /* |
| * The first chunk which always exists. Note that unlike other |
| * chunks, this one can be allocated and mapped in several different |
| * ways and thus often doesn't live in the vmalloc area. |
| */ |
| struct pcpu_chunk *pcpu_first_chunk __ro_after_init; |
| |
| /* |
| * Optional reserved chunk. This chunk reserves part of the first |
| * chunk and serves it for reserved allocations. When the reserved |
| * region doesn't exist, the following variable is NULL. |
| */ |
| struct pcpu_chunk *pcpu_reserved_chunk __ro_after_init; |
| |
| DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */ |
| static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop, map ext */ |
| |
| struct list_head *pcpu_chunk_lists __ro_after_init; /* chunk list slots */ |
| |
| /* chunks which need their map areas extended, protected by pcpu_lock */ |
| static LIST_HEAD(pcpu_map_extend_chunks); |
| |
| /* |
| * The number of empty populated pages, protected by pcpu_lock. |
| * The reserved chunk doesn't contribute to the count. |
| */ |
| int pcpu_nr_empty_pop_pages; |
| |
| /* |
| * The number of populated pages in use by the allocator, protected by |
| * pcpu_lock. This number is kept per a unit per chunk (i.e. when a page gets |
| * allocated/deallocated, it is allocated/deallocated in all units of a chunk |
| * and increments/decrements this count by 1). |
| */ |
| static unsigned long pcpu_nr_populated; |
| |
| /* |
| * Balance work is used to populate or destroy chunks asynchronously. We |
| * try to keep the number of populated free pages between |
| * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one |
| * empty chunk. |
| */ |
| static void pcpu_balance_workfn(struct work_struct *work); |
| static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn); |
| static bool pcpu_async_enabled __read_mostly; |
| static bool pcpu_atomic_alloc_failed; |
| |
| static void pcpu_schedule_balance_work(void) |
| { |
| if (pcpu_async_enabled) |
| schedule_work(&pcpu_balance_work); |
| } |
| |
| /** |
| * pcpu_addr_in_chunk - check if the address is served from this chunk |
| * @chunk: chunk of interest |
| * @addr: percpu address |
| * |
| * RETURNS: |
| * True if the address is served from this chunk. |
| */ |
| static bool pcpu_addr_in_chunk(struct pcpu_chunk *chunk, void *addr) |
| { |
| void *start_addr, *end_addr; |
| |
| if (!chunk) |
| return false; |
| |
| start_addr = chunk->base_addr + chunk->start_offset; |
| end_addr = chunk->base_addr + chunk->nr_pages * PAGE_SIZE - |
| chunk->end_offset; |
| |
| return addr >= start_addr && addr < end_addr; |
| } |
| |
| static int __pcpu_size_to_slot(int size) |
| { |
| int highbit = fls(size); /* size is in bytes */ |
| return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1); |
| } |
| |
| static int pcpu_size_to_slot(int size) |
| { |
| if (size == pcpu_unit_size) |
| return pcpu_free_slot; |
| return __pcpu_size_to_slot(size); |
| } |
| |
| static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) |
| { |
| const struct pcpu_block_md *chunk_md = &chunk->chunk_md; |
| |
| if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE || |
| chunk_md->contig_hint == 0) |
| return 0; |
| |
| return pcpu_size_to_slot(chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE); |
| } |
| |
| /* set the pointer to a chunk in a page struct */ |
| static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu) |
| { |
| page->index = (unsigned long)pcpu; |
| } |
| |
| /* obtain pointer to a chunk from a page struct */ |
| static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page) |
| { |
| return (struct pcpu_chunk *)page->index; |
| } |
| |
| static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx) |
| { |
| return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx; |
| } |
| |
| static unsigned long pcpu_unit_page_offset(unsigned int cpu, int page_idx) |
| { |
| return pcpu_unit_offsets[cpu] + (page_idx << PAGE_SHIFT); |
| } |
| |
| static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk, |
| unsigned int cpu, int page_idx) |
| { |
| return (unsigned long)chunk->base_addr + |
| pcpu_unit_page_offset(cpu, page_idx); |
| } |
| |
| /* |
| * The following are helper functions to help access bitmaps and convert |
| * between bitmap offsets to address offsets. |
| */ |
| static unsigned long *pcpu_index_alloc_map(struct pcpu_chunk *chunk, int index) |
| { |
| return chunk->alloc_map + |
| (index * PCPU_BITMAP_BLOCK_BITS / BITS_PER_LONG); |
| } |
| |
| static unsigned long pcpu_off_to_block_index(int off) |
| { |
| return off / PCPU_BITMAP_BLOCK_BITS; |
| } |
| |
| static unsigned long pcpu_off_to_block_off(int off) |
| { |
| return off & (PCPU_BITMAP_BLOCK_BITS - 1); |
| } |
| |
| static unsigned long pcpu_block_off_to_off(int index, int off) |
| { |
| return index * PCPU_BITMAP_BLOCK_BITS + off; |
| } |
| |
| /** |
| * pcpu_check_block_hint - check against the contig hint |
| * @block: block of interest |
| * @bits: size of allocation |
| * @align: alignment of area (max PAGE_SIZE) |
| * |
| * Check to see if the allocation can fit in the block's contig hint. |
| * Note, a chunk uses the same hints as a block so this can also check against |
| * the chunk's contig hint. |
| */ |
| static bool pcpu_check_block_hint(struct pcpu_block_md *block, int bits, |
| size_t align) |
| { |
| int bit_off = ALIGN(block->contig_hint_start, align) - |
| block->contig_hint_start; |
| |
| return bit_off + bits <= block->contig_hint; |
| } |
| |
| /* |
| * pcpu_next_hint - determine which hint to use |
| * @block: block of interest |
| * @alloc_bits: size of allocation |
| * |
| * This determines if we should scan based on the scan_hint or first_free. |
| * In general, we want to scan from first_free to fulfill allocations by |
| * first fit. However, if we know a scan_hint at position scan_hint_start |
| * cannot fulfill an allocation, we can begin scanning from there knowing |
| * the contig_hint will be our fallback. |
| */ |
| static int pcpu_next_hint(struct pcpu_block_md *block, int alloc_bits) |
| { |
| /* |
| * The three conditions below determine if we can skip past the |
| * scan_hint. First, does the scan hint exist. Second, is the |
| * contig_hint after the scan_hint (possibly not true iff |
| * contig_hint == scan_hint). Third, is the allocation request |
| * larger than the scan_hint. |
| */ |
| if (block->scan_hint && |
| block->contig_hint_start > block->scan_hint_start && |
| alloc_bits > block->scan_hint) |
| return block->scan_hint_start + block->scan_hint; |
| |
| return block->first_free; |
| } |
| |
| /** |
| * pcpu_next_md_free_region - finds the next hint free area |
| * @chunk: chunk of interest |
| * @bit_off: chunk offset |
| * @bits: size of free area |
| * |
| * Helper function for pcpu_for_each_md_free_region. It checks |
| * block->contig_hint and performs aggregation across blocks to find the |
| * next hint. It modifies bit_off and bits in-place to be consumed in the |
| * loop. |
| */ |
| static void pcpu_next_md_free_region(struct pcpu_chunk *chunk, int *bit_off, |
| int *bits) |
| { |
| int i = pcpu_off_to_block_index(*bit_off); |
| int block_off = pcpu_off_to_block_off(*bit_off); |
| struct pcpu_block_md *block; |
| |
| *bits = 0; |
| for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk); |
| block++, i++) { |
| /* handles contig area across blocks */ |
| if (*bits) { |
| *bits += block->left_free; |
| if (block->left_free == PCPU_BITMAP_BLOCK_BITS) |
| continue; |
| return; |
| } |
| |
| /* |
| * This checks three things. First is there a contig_hint to |
| * check. Second, have we checked this hint before by |
| * comparing the block_off. Third, is this the same as the |
| * right contig hint. In the last case, it spills over into |
| * the next block and should be handled by the contig area |
| * across blocks code. |
| */ |
| *bits = block->contig_hint; |
| if (*bits && block->contig_hint_start >= block_off && |
| *bits + block->contig_hint_start < PCPU_BITMAP_BLOCK_BITS) { |
| *bit_off = pcpu_block_off_to_off(i, |
| block->contig_hint_start); |
| return; |
| } |
| /* reset to satisfy the second predicate above */ |
| block_off = 0; |
| |
| *bits = block->right_free; |
| *bit_off = (i + 1) * PCPU_BITMAP_BLOCK_BITS - block->right_free; |
| } |
| } |
| |
| /** |
| * pcpu_next_fit_region - finds fit areas for a given allocation request |
| * @chunk: chunk of interest |
| * @alloc_bits: size of allocation |
| * @align: alignment of area (max PAGE_SIZE) |
| * @bit_off: chunk offset |
| * @bits: size of free area |
| * |
| * Finds the next free region that is viable for use with a given size and |
| * alignment. This only returns if there is a valid area to be used for this |
| * allocation. block->first_free is returned if the allocation request fits |
| * within the block to see if the request can be fulfilled prior to the contig |
| * hint. |
| */ |
| static void pcpu_next_fit_region(struct pcpu_chunk *chunk, int alloc_bits, |
| int align, int *bit_off, int *bits) |
| { |
| int i = pcpu_off_to_block_index(*bit_off); |
| int block_off = pcpu_off_to_block_off(*bit_off); |
| struct pcpu_block_md *block; |
| |
| *bits = 0; |
| for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk); |
| block++, i++) { |
| /* handles contig area across blocks */ |
| if (*bits) { |
| *bits += block->left_free; |
| if (*bits >= alloc_bits) |
| return; |
| if (block->left_free == PCPU_BITMAP_BLOCK_BITS) |
| continue; |
| } |
| |
| /* check block->contig_hint */ |
| *bits = ALIGN(block->contig_hint_start, align) - |
| block->contig_hint_start; |
| /* |
| * This uses the block offset to determine if this has been |
| * checked in the prior iteration. |
| */ |
| if (block->contig_hint && |
| block->contig_hint_start >= block_off && |
| block->contig_hint >= *bits + alloc_bits) { |
| int start = pcpu_next_hint(block, alloc_bits); |
| |
| *bits += alloc_bits + block->contig_hint_start - |
| start; |
| *bit_off = pcpu_block_off_to_off(i, start); |
| return; |
| } |
| /* reset to satisfy the second predicate above */ |
| block_off = 0; |
| |
| *bit_off = ALIGN(PCPU_BITMAP_BLOCK_BITS - block->right_free, |
| align); |
| *bits = PCPU_BITMAP_BLOCK_BITS - *bit_off; |
| *bit_off = pcpu_block_off_to_off(i, *bit_off); |
| if (*bits >= alloc_bits) |
| return; |
| } |
| |
| /* no valid offsets were found - fail condition */ |
| *bit_off = pcpu_chunk_map_bits(chunk); |
| } |
| |
| /* |
| * Metadata free area iterators. These perform aggregation of free areas |
| * based on the metadata blocks and return the offset @bit_off and size in |
| * bits of the free area @bits. pcpu_for_each_fit_region only returns when |
| * a fit is found for the allocation request. |
| */ |
| #define pcpu_for_each_md_free_region(chunk, bit_off, bits) \ |
| for (pcpu_next_md_free_region((chunk), &(bit_off), &(bits)); \ |
| (bit_off) < pcpu_chunk_map_bits((chunk)); \ |
| (bit_off) += (bits) + 1, \ |
| pcpu_next_md_free_region((chunk), &(bit_off), &(bits))) |
| |
| #define pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) \ |
| for (pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \ |
| &(bits)); \ |
| (bit_off) < pcpu_chunk_map_bits((chunk)); \ |
| (bit_off) += (bits), \ |
| pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \ |
| &(bits))) |
| |
| /** |
| * pcpu_mem_zalloc - allocate memory |
| * @size: bytes to allocate |
| * @gfp: allocation flags |
| * |
| * Allocate @size bytes. If @size is smaller than PAGE_SIZE, |
| * kzalloc() is used; otherwise, the equivalent of vzalloc() is used. |
| * This is to facilitate passing through whitelisted flags. The |
| * returned memory is always zeroed. |
| * |
| * RETURNS: |
| * Pointer to the allocated area on success, NULL on failure. |
| */ |
| static void *pcpu_mem_zalloc(size_t size, gfp_t gfp) |
| { |
| if (WARN_ON_ONCE(!slab_is_available())) |
| return NULL; |
| |
| if (size <= PAGE_SIZE) |
| return kzalloc(size, gfp); |
| else |
| return __vmalloc(size, gfp | __GFP_ZERO); |
| } |
| |
| /** |
| * pcpu_mem_free - free memory |
| * @ptr: memory to free |
| * |
| * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc(). |
| */ |
| static void pcpu_mem_free(void *ptr) |
| { |
| kvfree(ptr); |
| } |
| |
| static void __pcpu_chunk_move(struct pcpu_chunk *chunk, int slot, |
| bool move_front) |
| { |
| if (chunk != pcpu_reserved_chunk) { |
| if (move_front) |
| list_move(&chunk->list, &pcpu_chunk_lists[slot]); |
| else |
| list_move_tail(&chunk->list, &pcpu_chunk_lists[slot]); |
| } |
| } |
| |
| static void pcpu_chunk_move(struct pcpu_chunk *chunk, int slot) |
| { |
| __pcpu_chunk_move(chunk, slot, true); |
| } |
| |
| /** |
| * pcpu_chunk_relocate - put chunk in the appropriate chunk slot |
| * @chunk: chunk of interest |
| * @oslot: the previous slot it was on |
| * |
| * This function is called after an allocation or free changed @chunk. |
| * New slot according to the changed state is determined and @chunk is |
| * moved to the slot. Note that the reserved chunk is never put on |
| * chunk slots. |
| * |
| * CONTEXT: |
| * pcpu_lock. |
| */ |
| static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot) |
| { |
| int nslot = pcpu_chunk_slot(chunk); |
| |
| /* leave isolated chunks in-place */ |
| if (chunk->isolated) |
| return; |
| |
| if (oslot != nslot) |
| __pcpu_chunk_move(chunk, nslot, oslot < nslot); |
| } |
| |
| static void pcpu_isolate_chunk(struct pcpu_chunk *chunk) |
| { |
| lockdep_assert_held(&pcpu_lock); |
| |
| if (!chunk->isolated) { |
| chunk->isolated = true; |
| pcpu_nr_empty_pop_pages -= chunk->nr_empty_pop_pages; |
| } |
| list_move(&chunk->list, &pcpu_chunk_lists[pcpu_to_depopulate_slot]); |
| } |
| |
| static void pcpu_reintegrate_chunk(struct pcpu_chunk *chunk) |
| { |
| lockdep_assert_held(&pcpu_lock); |
| |
| if (chunk->isolated) { |
| chunk->isolated = false; |
| pcpu_nr_empty_pop_pages += chunk->nr_empty_pop_pages; |
| pcpu_chunk_relocate(chunk, -1); |
| } |
| } |
| |
| /* |
| * pcpu_update_empty_pages - update empty page counters |
| * @chunk: chunk of interest |
| * @nr: nr of empty pages |
| * |
| * This is used to keep track of the empty pages now based on the premise |
| * a md_block covers a page. The hint update functions recognize if a block |
| * is made full or broken to calculate deltas for keeping track of free pages. |
| */ |
| static inline void pcpu_update_empty_pages(struct pcpu_chunk *chunk, int nr) |
| { |
| chunk->nr_empty_pop_pages += nr; |
| if (chunk != pcpu_reserved_chunk && !chunk->isolated) |
| pcpu_nr_empty_pop_pages += nr; |
| } |
| |
| /* |
| * pcpu_region_overlap - determines if two regions overlap |
| * @a: start of first region, inclusive |
| * @b: end of first region, exclusive |
| * @x: start of second region, inclusive |
| * @y: end of second region, exclusive |
| * |
| * This is used to determine if the hint region [a, b) overlaps with the |
| * allocated region [x, y). |
| */ |
| static inline bool pcpu_region_overlap(int a, int b, int x, int y) |
| { |
| return (a < y) && (x < b); |
| } |
| |
| /** |
| * pcpu_block_update - updates a block given a free area |
| * @block: block of interest |
| * @start: start offset in block |
| * @end: end offset in block |
| * |
| * Updates a block given a known free area. The region [start, end) is |
| * expected to be the entirety of the free area within a block. Chooses |
| * the best starting offset if the contig hints are equal. |
| */ |
| static void pcpu_block_update(struct pcpu_block_md *block, int start, int end) |
| { |
| int contig = end - start; |
| |
| block->first_free = min(block->first_free, start); |
| if (start == 0) |
| block->left_free = contig; |
| |
| if (end == block->nr_bits) |
| block->right_free = contig; |
| |
| if (contig > block->contig_hint) { |
| /* promote the old contig_hint to be the new scan_hint */ |
| if (start > block->contig_hint_start) { |
| if (block->contig_hint > block->scan_hint) { |
| block->scan_hint_start = |
| block->contig_hint_start; |
| block->scan_hint = block->contig_hint; |
| } else if (start < block->scan_hint_start) { |
| /* |
| * The old contig_hint == scan_hint. But, the |
| * new contig is larger so hold the invariant |
| * scan_hint_start < contig_hint_start. |
| */ |
| block->scan_hint = 0; |
| } |
| } else { |
| block->scan_hint = 0; |
| } |
| block->contig_hint_start = start; |
| block->contig_hint = contig; |
| } else if (contig == block->contig_hint) { |
| if (block->contig_hint_start && |
| (!start || |
| __ffs(start) > __ffs(block->contig_hint_start))) { |
| /* start has a better alignment so use it */ |
| block->contig_hint_start = start; |
| if (start < block->scan_hint_start && |
| block->contig_hint > block->scan_hint) |
| block->scan_hint = 0; |
| } else if (start > block->scan_hint_start || |
| block->contig_hint > block->scan_hint) { |
| /* |
| * Knowing contig == contig_hint, update the scan_hint |
| * if it is farther than or larger than the current |
| * scan_hint. |
| */ |
| block->scan_hint_start = start; |
| block->scan_hint = contig; |
| } |
| } else { |
| /* |
| * The region is smaller than the contig_hint. So only update |
| * the scan_hint if it is larger than or equal and farther than |
| * the current scan_hint. |
| */ |
| if ((start < block->contig_hint_start && |
| (contig > block->scan_hint || |
| (contig == block->scan_hint && |
| start > block->scan_hint_start)))) { |
| block->scan_hint_start = start; |
| block->scan_hint = contig; |
| } |
| } |
| } |
| |
| /* |
| * pcpu_block_update_scan - update a block given a free area from a scan |
| * @chunk: chunk of interest |
| * @bit_off: chunk offset |
| * @bits: size of free area |
| * |
| * Finding the final allocation spot first goes through pcpu_find_block_fit() |
| * to find a block that can hold the allocation and then pcpu_alloc_area() |
| * where a scan is used. When allocations require specific alignments, |
| * we can inadvertently create holes which will not be seen in the alloc |
| * or free paths. |
| * |
| * This takes a given free area hole and updates a block as it may change the |
| * scan_hint. We need to scan backwards to ensure we don't miss free bits |
| * from alignment. |
| */ |
| static void pcpu_block_update_scan(struct pcpu_chunk *chunk, int bit_off, |
| int bits) |
| { |
| int s_off = pcpu_off_to_block_off(bit_off); |
| int e_off = s_off + bits; |
| int s_index, l_bit; |
| struct pcpu_block_md *block; |
| |
| if (e_off > PCPU_BITMAP_BLOCK_BITS) |
| return; |
| |
| s_index = pcpu_off_to_block_index(bit_off); |
| block = chunk->md_blocks + s_index; |
| |
| /* scan backwards in case of alignment skipping free bits */ |
| l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index), s_off); |
| s_off = (s_off == l_bit) ? 0 : l_bit + 1; |
| |
| pcpu_block_update(block, s_off, e_off); |
| } |
| |
| /** |
| * pcpu_chunk_refresh_hint - updates metadata about a chunk |
| * @chunk: chunk of interest |
| * @full_scan: if we should scan from the beginning |
| * |
| * Iterates over the metadata blocks to find the largest contig area. |
| * A full scan can be avoided on the allocation path as this is triggered |
| * if we broke the contig_hint. In doing so, the scan_hint will be before |
| * the contig_hint or after if the scan_hint == contig_hint. This cannot |
| * be prevented on freeing as we want to find the largest area possibly |
| * spanning blocks. |
| */ |
| static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk, bool full_scan) |
| { |
| struct pcpu_block_md *chunk_md = &chunk->chunk_md; |
| int bit_off, bits; |
| |
| /* promote scan_hint to contig_hint */ |
| if (!full_scan && chunk_md->scan_hint) { |
| bit_off = chunk_md->scan_hint_start + chunk_md->scan_hint; |
| chunk_md->contig_hint_start = chunk_md->scan_hint_start; |
| chunk_md->contig_hint = chunk_md->scan_hint; |
| chunk_md->scan_hint = 0; |
| } else { |
| bit_off = chunk_md->first_free; |
| chunk_md->contig_hint = 0; |
| } |
| |
| bits = 0; |
| pcpu_for_each_md_free_region(chunk, bit_off, bits) |
| pcpu_block_update(chunk_md, bit_off, bit_off + bits); |
| } |
| |
| /** |
| * pcpu_block_refresh_hint |
| * @chunk: chunk of interest |
| * @index: index of the metadata block |
| * |
| * Scans over the block beginning at first_free and updates the block |
| * metadata accordingly. |
| */ |
| static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index) |
| { |
| struct pcpu_block_md *block = chunk->md_blocks + index; |
| unsigned long *alloc_map = pcpu_index_alloc_map(chunk, index); |
| unsigned int rs, re, start; /* region start, region end */ |
| |
| /* promote scan_hint to contig_hint */ |
| if (block->scan_hint) { |
| start = block->scan_hint_start + block->scan_hint; |
| block->contig_hint_start = block->scan_hint_start; |
| block->contig_hint = block->scan_hint; |
| block->scan_hint = 0; |
| } else { |
| start = block->first_free; |
| block->contig_hint = 0; |
| } |
| |
| block->right_free = 0; |
| |
| /* iterate over free areas and update the contig hints */ |
| bitmap_for_each_clear_region(alloc_map, rs, re, start, |
| PCPU_BITMAP_BLOCK_BITS) |
| pcpu_block_update(block, rs, re); |
| } |
| |
| /** |
| * pcpu_block_update_hint_alloc - update hint on allocation path |
| * @chunk: chunk of interest |
| * @bit_off: chunk offset |
| * @bits: size of request |
| * |
| * Updates metadata for the allocation path. The metadata only has to be |
| * refreshed by a full scan iff the chunk's contig hint is broken. Block level |
| * scans are required if the block's contig hint is broken. |
| */ |
| static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off, |
| int bits) |
| { |
| struct pcpu_block_md *chunk_md = &chunk->chunk_md; |
| int nr_empty_pages = 0; |
| struct pcpu_block_md *s_block, *e_block, *block; |
| int s_index, e_index; /* block indexes of the freed allocation */ |
| int s_off, e_off; /* block offsets of the freed allocation */ |
| |
| /* |
| * Calculate per block offsets. |
| * The calculation uses an inclusive range, but the resulting offsets |
| * are [start, end). e_index always points to the last block in the |
| * range. |
| */ |
| s_index = pcpu_off_to_block_index(bit_off); |
| e_index = pcpu_off_to_block_index(bit_off + bits - 1); |
| s_off = pcpu_off_to_block_off(bit_off); |
| e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1; |
| |
| s_block = chunk->md_blocks + s_index; |
| e_block = chunk->md_blocks + e_index; |
| |
| /* |
| * Update s_block. |
| * block->first_free must be updated if the allocation takes its place. |
| * If the allocation breaks the contig_hint, a scan is required to |
| * restore this hint. |
| */ |
| if (s_block->contig_hint == PCPU_BITMAP_BLOCK_BITS) |
| nr_empty_pages++; |
| |
| if (s_off == s_block->first_free) |
| s_block->first_free = find_next_zero_bit( |
| pcpu_index_alloc_map(chunk, s_index), |
| PCPU_BITMAP_BLOCK_BITS, |
| s_off + bits); |
| |
| if (pcpu_region_overlap(s_block->scan_hint_start, |
| s_block->scan_hint_start + s_block->scan_hint, |
| s_off, |
| s_off + bits)) |
| s_block->scan_hint = 0; |
| |
| if (pcpu_region_overlap(s_block->contig_hint_start, |
| s_block->contig_hint_start + |
| s_block->contig_hint, |
| s_off, |
| s_off + bits)) { |
| /* block contig hint is broken - scan to fix it */ |
| if (!s_off) |
| s_block->left_free = 0; |
| pcpu_block_refresh_hint(chunk, s_index); |
| } else { |
| /* update left and right contig manually */ |
| s_block->left_free = min(s_block->left_free, s_off); |
| if (s_index == e_index) |
| s_block->right_free = min_t(int, s_block->right_free, |
| PCPU_BITMAP_BLOCK_BITS - e_off); |
| else |
| s_block->right_free = 0; |
| } |
| |
| /* |
| * Update e_block. |
| */ |
| if (s_index != e_index) { |
| if (e_block->contig_hint == PCPU_BITMAP_BLOCK_BITS) |
| nr_empty_pages++; |
| |
| /* |
| * When the allocation is across blocks, the end is along |
| * the left part of the e_block. |
| */ |
| e_block->first_free = find_next_zero_bit( |
| pcpu_index_alloc_map(chunk, e_index), |
| PCPU_BITMAP_BLOCK_BITS, e_off); |
| |
| if (e_off == PCPU_BITMAP_BLOCK_BITS) { |
| /* reset the block */ |
| e_block++; |
| } else { |
| if (e_off > e_block->scan_hint_start) |
| e_block->scan_hint = 0; |
| |
| e_block->left_free = 0; |
| if (e_off > e_block->contig_hint_start) { |
| /* contig hint is broken - scan to fix it */ |
| pcpu_block_refresh_hint(chunk, e_index); |
| } else { |
| e_block->right_free = |
| min_t(int, e_block->right_free, |
| PCPU_BITMAP_BLOCK_BITS - e_off); |
| } |
| } |
| |
| /* update in-between md_blocks */ |
| nr_empty_pages += (e_index - s_index - 1); |
| for (block = s_block + 1; block < e_block; block++) { |
| block->scan_hint = 0; |
| block->contig_hint = 0; |
| block->left_free = 0; |
| block->right_free = 0; |
| } |
| } |
| |
| if (nr_empty_pages) |
| pcpu_update_empty_pages(chunk, -nr_empty_pages); |
| |
| if (pcpu_region_overlap(chunk_md->scan_hint_start, |
| chunk_md->scan_hint_start + |
| chunk_md->scan_hint, |
| bit_off, |
| bit_off + bits)) |
| chunk_md->scan_hint = 0; |
| |
| /* |
| * The only time a full chunk scan is required is if the chunk |
| * contig hint is broken. Otherwise, it means a smaller space |
| * was used and therefore the chunk contig hint is still correct. |
| */ |
| if (pcpu_region_overlap(chunk_md->contig_hint_start, |
| chunk_md->contig_hint_start + |
| chunk_md->contig_hint, |
| bit_off, |
| bit_off + bits)) |
| pcpu_chunk_refresh_hint(chunk, false); |
| } |
| |
| /** |
| * pcpu_block_update_hint_free - updates the block hints on the free path |
| * @chunk: chunk of interest |
| * @bit_off: chunk offset |
| * @bits: size of request |
| * |
| * Updates metadata for the allocation path. This avoids a blind block |
| * refresh by making use of the block contig hints. If this fails, it scans |
| * forward and backward to determine the extent of the free area. This is |
| * capped at the boundary of blocks. |
| * |
| * A chunk update is triggered if a page becomes free, a block becomes free, |
| * or the free spans across blocks. This tradeoff is to minimize iterating |
| * over the block metadata to update chunk_md->contig_hint. |
| * chunk_md->contig_hint may be off by up to a page, but it will never be more |
| * than the available space. If the contig hint is contained in one block, it |
| * will be accurate. |
| */ |
| static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off, |
| int bits) |
| { |
| int nr_empty_pages = 0; |
| struct pcpu_block_md *s_block, *e_block, *block; |
| int s_index, e_index; /* block indexes of the freed allocation */ |
| int s_off, e_off; /* block offsets of the freed allocation */ |
| int start, end; /* start and end of the whole free area */ |
| |
| /* |
| * Calculate per block offsets. |
| * The calculation uses an inclusive range, but the resulting offsets |
| * are [start, end). e_index always points to the last block in the |
| * range. |
| */ |
| s_index = pcpu_off_to_block_index(bit_off); |
| e_index = pcpu_off_to_block_index(bit_off + bits - 1); |
| s_off = pcpu_off_to_block_off(bit_off); |
| e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1; |
| |
| s_block = chunk->md_blocks + s_index; |
| e_block = chunk->md_blocks + e_index; |
| |
| /* |
| * Check if the freed area aligns with the block->contig_hint. |
| * If it does, then the scan to find the beginning/end of the |
| * larger free area can be avoided. |
| * |
| * start and end refer to beginning and end of the free area |
| * within each their respective blocks. This is not necessarily |
| * the entire free area as it may span blocks past the beginning |
| * or end of the block. |
| */ |
| start = s_off; |
| if (s_off == s_block->contig_hint + s_block->contig_hint_start) { |
| start = s_block->contig_hint_start; |
| } else { |
| /* |
| * Scan backwards to find the extent of the free area. |
| * find_last_bit returns the starting bit, so if the start bit |
| * is returned, that means there was no last bit and the |
| * remainder of the chunk is free. |
| */ |
| int l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index), |
| start); |
| start = (start == l_bit) ? 0 : l_bit + 1; |
| } |
| |
| end = e_off; |
| if (e_off == e_block->contig_hint_start) |
| end = e_block->contig_hint_start + e_block->contig_hint; |
| else |
| end = find_next_bit(pcpu_index_alloc_map(chunk, e_index), |
| PCPU_BITMAP_BLOCK_BITS, end); |
| |
| /* update s_block */ |
| e_off = (s_index == e_index) ? end : PCPU_BITMAP_BLOCK_BITS; |
| if (!start && e_off == PCPU_BITMAP_BLOCK_BITS) |
| nr_empty_pages++; |
| pcpu_block_update(s_block, start, e_off); |
| |
| /* freeing in the same block */ |
| if (s_index != e_index) { |
| /* update e_block */ |
| if (end == PCPU_BITMAP_BLOCK_BITS) |
| nr_empty_pages++; |
| pcpu_block_update(e_block, 0, end); |
| |
| /* reset md_blocks in the middle */ |
| nr_empty_pages += (e_index - s_index - 1); |
| for (block = s_block + 1; block < e_block; block++) { |
| block->first_free = 0; |
| block->scan_hint = 0; |
| block->contig_hint_start = 0; |
| block->contig_hint = PCPU_BITMAP_BLOCK_BITS; |
| block->left_free = PCPU_BITMAP_BLOCK_BITS; |
| block->right_free = PCPU_BITMAP_BLOCK_BITS; |
| } |
| } |
| |
| if (nr_empty_pages) |
| pcpu_update_empty_pages(chunk, nr_empty_pages); |
| |
| /* |
| * Refresh chunk metadata when the free makes a block free or spans |
| * across blocks. The contig_hint may be off by up to a page, but if |
| * the contig_hint is contained in a block, it will be accurate with |
| * the else condition below. |
| */ |
| if (((end - start) >= PCPU_BITMAP_BLOCK_BITS) || s_index != e_index) |
| pcpu_chunk_refresh_hint(chunk, true); |
| else |
| pcpu_block_update(&chunk->chunk_md, |
| pcpu_block_off_to_off(s_index, start), |
| end); |
| } |
| |
| /** |
| * pcpu_is_populated - determines if the region is populated |
| * @chunk: chunk of interest |
| * @bit_off: chunk offset |
| * @bits: size of area |
| * @next_off: return value for the next offset to start searching |
| * |
| * For atomic allocations, check if the backing pages are populated. |
| * |
| * RETURNS: |
| * Bool if the backing pages are populated. |
| * next_index is to skip over unpopulated blocks in pcpu_find_block_fit. |
| */ |
| static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits, |
| int *next_off) |
| { |
| unsigned int page_start, page_end, rs, re; |
| |
| page_start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); |
| page_end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); |
| |
| rs = page_start; |
| bitmap_next_clear_region(chunk->populated, &rs, &re, page_end); |
| if (rs >= page_end) |
| return true; |
| |
| *next_off = re * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; |
| return false; |
| } |
| |
| /** |
| * pcpu_find_block_fit - finds the block index to start searching |
| * @chunk: chunk of interest |
| * @alloc_bits: size of request in allocation units |
| * @align: alignment of area (max PAGE_SIZE bytes) |
| * @pop_only: use populated regions only |
| * |
| * Given a chunk and an allocation spec, find the offset to begin searching |
| * for a free region. This iterates over the bitmap metadata blocks to |
| * find an offset that will be guaranteed to fit the requirements. It is |
| * not quite first fit as if the allocation does not fit in the contig hint |
| * of a block or chunk, it is skipped. This errs on the side of caution |
| * to prevent excess iteration. Poor alignment can cause the allocator to |
| * skip over blocks and chunks that have valid free areas. |
| * |
| * RETURNS: |
| * The offset in the bitmap to begin searching. |
| * -1 if no offset is found. |
| */ |
| static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, |
| size_t align, bool pop_only) |
| { |
| struct pcpu_block_md *chunk_md = &chunk->chunk_md; |
| int bit_off, bits, next_off; |
| |
| /* |
| * This is an optimization to prevent scanning by assuming if the |
| * allocation cannot fit in the global hint, there is memory pressure |
| * and creating a new chunk would happen soon. |
| */ |
| if (!pcpu_check_block_hint(chunk_md, alloc_bits, align)) |
| return -1; |
| |
| bit_off = pcpu_next_hint(chunk_md, alloc_bits); |
| bits = 0; |
| pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) { |
| if (!pop_only || pcpu_is_populated(chunk, bit_off, bits, |
| &next_off)) |
| break; |
| |
| bit_off = next_off; |
| bits = 0; |
| } |
| |
| if (bit_off == pcpu_chunk_map_bits(chunk)) |
| return -1; |
| |
| return bit_off; |
| } |
| |
| /* |
| * pcpu_find_zero_area - modified from bitmap_find_next_zero_area_off() |
| * @map: the address to base the search on |
| * @size: the bitmap size in bits |
| * @start: the bitnumber to start searching at |
| * @nr: the number of zeroed bits we're looking for |
| * @align_mask: alignment mask for zero area |
| * @largest_off: offset of the largest area skipped |
| * @largest_bits: size of the largest area skipped |
| * |
| * The @align_mask should be one less than a power of 2. |
| * |
| * This is a modified version of bitmap_find_next_zero_area_off() to remember |
| * the largest area that was skipped. This is imperfect, but in general is |
| * good enough. The largest remembered region is the largest failed region |
| * seen. This does not include anything we possibly skipped due to alignment. |
| * pcpu_block_update_scan() does scan backwards to try and recover what was |
| * lost to alignment. While this can cause scanning to miss earlier possible |
| * free areas, smaller allocations will eventually fill those holes. |
| */ |
| static unsigned long pcpu_find_zero_area(unsigned long *map, |
| unsigned long size, |
| unsigned long start, |
| unsigned long nr, |
| unsigned long align_mask, |
| unsigned long *largest_off, |
| unsigned long *largest_bits) |
| { |
| unsigned long index, end, i, area_off, area_bits; |
| again: |
| index = find_next_zero_bit(map, size, start); |
| |
| /* Align allocation */ |
| index = __ALIGN_MASK(index, align_mask); |
| area_off = index; |
| |
| end = index + nr; |
| if (end > size) |
| return end; |
| i = find_next_bit(map, end, index); |
| if (i < end) { |
| area_bits = i - area_off; |
| /* remember largest unused area with best alignment */ |
| if (area_bits > *largest_bits || |
| (area_bits == *largest_bits && *largest_off && |
| (!area_off || __ffs(area_off) > __ffs(*largest_off)))) { |
| *largest_off = area_off; |
| *largest_bits = area_bits; |
| } |
| |
| start = i + 1; |
| goto again; |
| } |
| return index; |
| } |
| |
| /** |
| * pcpu_alloc_area - allocates an area from a pcpu_chunk |
| * @chunk: chunk of interest |
| * @alloc_bits: size of request in allocation units |
| * @align: alignment of area (max PAGE_SIZE) |
| * @start: bit_off to start searching |
| * |
| * This function takes in a @start offset to begin searching to fit an |
| * allocation of @alloc_bits with alignment @align. It needs to scan |
| * the allocation map because if it fits within the block's contig hint, |
| * @start will be block->first_free. This is an attempt to fill the |
| * allocation prior to breaking the contig hint. The allocation and |
| * boundary maps are updated accordingly if it confirms a valid |
| * free area. |
| * |
| * RETURNS: |
| * Allocated addr offset in @chunk on success. |
| * -1 if no matching area is found. |
| */ |
| static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, |
| size_t align, int start) |
| { |
| struct pcpu_block_md *chunk_md = &chunk->chunk_md; |
| size_t align_mask = (align) ? (align - 1) : 0; |
| unsigned long area_off = 0, area_bits = 0; |
| int bit_off, end, oslot; |
| |
| lockdep_assert_held(&pcpu_lock); |
| |
| oslot = pcpu_chunk_slot(chunk); |
| |
| /* |
| * Search to find a fit. |
| */ |
| end = min_t(int, start + alloc_bits + PCPU_BITMAP_BLOCK_BITS, |
| pcpu_chunk_map_bits(chunk)); |
| bit_off = pcpu_find_zero_area(chunk->alloc_map, end, start, alloc_bits, |
| align_mask, &area_off, &area_bits); |
| if (bit_off >= end) |
| return -1; |
| |
| if (area_bits) |
| pcpu_block_update_scan(chunk, area_off, area_bits); |
| |
| /* update alloc map */ |
| bitmap_set(chunk->alloc_map, bit_off, alloc_bits); |
| |
| /* update boundary map */ |
| set_bit(bit_off, chunk->bound_map); |
| bitmap_clear(chunk->bound_map, bit_off + 1, alloc_bits - 1); |
| set_bit(bit_off + alloc_bits, chunk->bound_map); |
| |
| chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE; |
| |
| /* update first free bit */ |
| if (bit_off == chunk_md->first_free) |
| chunk_md->first_free = find_next_zero_bit( |
| chunk->alloc_map, |
| pcpu_chunk_map_bits(chunk), |
| bit_off + alloc_bits); |
| |
| pcpu_block_update_hint_alloc(chunk, bit_off, alloc_bits); |
| |
| pcpu_chunk_relocate(chunk, oslot); |
| |
| return bit_off * PCPU_MIN_ALLOC_SIZE; |
| } |
| |
| /** |
| * pcpu_free_area - frees the corresponding offset |
| * @chunk: chunk of interest |
| * @off: addr offset into chunk |
| * |
| * This function determines the size of an allocation to free using |
| * the boundary bitmap and clears the allocation map. |
| * |
| * RETURNS: |
| * Number of freed bytes. |
| */ |
| static int pcpu_free_area(struct pcpu_chunk *chunk, int off) |
| { |
| struct pcpu_block_md *chunk_md = &chunk->chunk_md; |
| int bit_off, bits, end, oslot, freed; |
| |
| lockdep_assert_held(&pcpu_lock); |
| pcpu_stats_area_dealloc(chunk); |
| |
| oslot = pcpu_chunk_slot(chunk); |
| |
| bit_off = off / PCPU_MIN_ALLOC_SIZE; |
| |
| /* find end index */ |
| end = find_next_bit(chunk->bound_map, pcpu_chunk_map_bits(chunk), |
| bit_off + 1); |
| bits = end - bit_off; |
| bitmap_clear(chunk->alloc_map, bit_off, bits); |
| |
| freed = bits * PCPU_MIN_ALLOC_SIZE; |
| |
| /* update metadata */ |
| chunk->free_bytes += freed; |
| |
| /* update first free bit */ |
| chunk_md->first_free = min(chunk_md->first_free, bit_off); |
| |
| pcpu_block_update_hint_free(chunk, bit_off, bits); |
| |
| pcpu_chunk_relocate(chunk, oslot); |
| |
| return freed; |
| } |
| |
| static void pcpu_init_md_block(struct pcpu_block_md *block, int nr_bits) |
| { |
| block->scan_hint = 0; |
| block->contig_hint = nr_bits; |
| block->left_free = nr_bits; |
| block->right_free = nr_bits; |
| block->first_free = 0; |
| block->nr_bits = nr_bits; |
| } |
| |
| static void pcpu_init_md_blocks(struct pcpu_chunk *chunk) |
| { |
| struct pcpu_block_md *md_block; |
| |
| /* init the chunk's block */ |
| pcpu_init_md_block(&chunk->chunk_md, pcpu_chunk_map_bits(chunk)); |
| |
| for (md_block = chunk->md_blocks; |
| md_block != chunk->md_blocks + pcpu_chunk_nr_blocks(chunk); |
| md_block++) |
| pcpu_init_md_block(md_block, PCPU_BITMAP_BLOCK_BITS); |
| } |
| |
| /** |
| * pcpu_alloc_first_chunk - creates chunks that serve the first chunk |
| * @tmp_addr: the start of the region served |
| * @map_size: size of the region served |
| * |
| * This is responsible for creating the chunks that serve the first chunk. The |
| * base_addr is page aligned down of @tmp_addr while the region end is page |
| * aligned up. Offsets are kept track of to determine the region served. All |
| * this is done to appease the bitmap allocator in avoiding partial blocks. |
| * |
| * RETURNS: |
| * Chunk serving the region at @tmp_addr of @map_size. |
| */ |
| static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, |
| int map_size) |
| { |
| struct pcpu_chunk *chunk; |
| unsigned long aligned_addr, lcm_align; |
| int start_offset, offset_bits, region_size, region_bits; |
| size_t alloc_size; |
| |
| /* region calculations */ |
| aligned_addr = tmp_addr & PAGE_MASK; |
| |
| start_offset = tmp_addr - aligned_addr; |
| |
| /* |
| * Align the end of the region with the LCM of PAGE_SIZE and |
| * PCPU_BITMAP_BLOCK_SIZE. One of these constants is a multiple of |
| * the other. |
| */ |
| lcm_align = lcm(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE); |
| region_size = ALIGN(start_offset + map_size, lcm_align); |
| |
| /* allocate chunk */ |
| alloc_size = struct_size(chunk, populated, |
| BITS_TO_LONGS(region_size >> PAGE_SHIFT)); |
| chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!chunk) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| INIT_LIST_HEAD(&chunk->list); |
| |
| chunk->base_addr = (void *)aligned_addr; |
| chunk->start_offset = start_offset; |
| chunk->end_offset = region_size - chunk->start_offset - map_size; |
| |
| chunk->nr_pages = region_size >> PAGE_SHIFT; |
| region_bits = pcpu_chunk_map_bits(chunk); |
| |
| alloc_size = BITS_TO_LONGS(region_bits) * sizeof(chunk->alloc_map[0]); |
| chunk->alloc_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!chunk->alloc_map) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| alloc_size = |
| BITS_TO_LONGS(region_bits + 1) * sizeof(chunk->bound_map[0]); |
| chunk->bound_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!chunk->bound_map) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| alloc_size = pcpu_chunk_nr_blocks(chunk) * sizeof(chunk->md_blocks[0]); |
| chunk->md_blocks = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!chunk->md_blocks) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| /* first chunk is free to use */ |
| chunk->obj_cgroups = NULL; |
| #endif |
| pcpu_init_md_blocks(chunk); |
| |
| /* manage populated page bitmap */ |
| chunk->immutable = true; |
| bitmap_fill(chunk->populated, chunk->nr_pages); |
| chunk->nr_populated = chunk->nr_pages; |
| chunk->nr_empty_pop_pages = chunk->nr_pages; |
| |
| chunk->free_bytes = map_size; |
| |
| if (chunk->start_offset) { |
| /* hide the beginning of the bitmap */ |
| offset_bits = chunk->start_offset / PCPU_MIN_ALLOC_SIZE; |
| bitmap_set(chunk->alloc_map, 0, offset_bits); |
| set_bit(0, chunk->bound_map); |
| set_bit(offset_bits, chunk->bound_map); |
| |
| chunk->chunk_md.first_free = offset_bits; |
| |
| pcpu_block_update_hint_alloc(chunk, 0, offset_bits); |
| } |
| |
| if (chunk->end_offset) { |
| /* hide the end of the bitmap */ |
| offset_bits = chunk->end_offset / PCPU_MIN_ALLOC_SIZE; |
| bitmap_set(chunk->alloc_map, |
| pcpu_chunk_map_bits(chunk) - offset_bits, |
| offset_bits); |
| set_bit((start_offset + map_size) / PCPU_MIN_ALLOC_SIZE, |
| chunk->bound_map); |
| set_bit(region_bits, chunk->bound_map); |
| |
| pcpu_block_update_hint_alloc(chunk, pcpu_chunk_map_bits(chunk) |
| - offset_bits, offset_bits); |
| } |
| |
| return chunk; |
| } |
| |
| static struct pcpu_chunk *pcpu_alloc_chunk(gfp_t gfp) |
| { |
| struct pcpu_chunk *chunk; |
| int region_bits; |
| |
| chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size, gfp); |
| if (!chunk) |
| return NULL; |
| |
| INIT_LIST_HEAD(&chunk->list); |
| chunk->nr_pages = pcpu_unit_pages; |
| region_bits = pcpu_chunk_map_bits(chunk); |
| |
| chunk->alloc_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits) * |
| sizeof(chunk->alloc_map[0]), gfp); |
| if (!chunk->alloc_map) |
| goto alloc_map_fail; |
| |
| chunk->bound_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits + 1) * |
| sizeof(chunk->bound_map[0]), gfp); |
| if (!chunk->bound_map) |
| goto bound_map_fail; |
| |
| chunk->md_blocks = pcpu_mem_zalloc(pcpu_chunk_nr_blocks(chunk) * |
| sizeof(chunk->md_blocks[0]), gfp); |
| if (!chunk->md_blocks) |
| goto md_blocks_fail; |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| if (!mem_cgroup_kmem_disabled()) { |
| chunk->obj_cgroups = |
| pcpu_mem_zalloc(pcpu_chunk_map_bits(chunk) * |
| sizeof(struct obj_cgroup *), gfp); |
| if (!chunk->obj_cgroups) |
| goto objcg_fail; |
| } |
| #endif |
| |
| pcpu_init_md_blocks(chunk); |
| |
| /* init metadata */ |
| chunk->free_bytes = chunk->nr_pages * PAGE_SIZE; |
| |
| return chunk; |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| objcg_fail: |
| pcpu_mem_free(chunk->md_blocks); |
| #endif |
| md_blocks_fail: |
| pcpu_mem_free(chunk->bound_map); |
| bound_map_fail: |
| pcpu_mem_free(chunk->alloc_map); |
| alloc_map_fail: |
| pcpu_mem_free(chunk); |
| |
| return NULL; |
| } |
| |
| static void pcpu_free_chunk(struct pcpu_chunk *chunk) |
| { |
| if (!chunk) |
| return; |
| #ifdef CONFIG_MEMCG_KMEM |
| pcpu_mem_free(chunk->obj_cgroups); |
| #endif |
| pcpu_mem_free(chunk->md_blocks); |
| pcpu_mem_free(chunk->bound_map); |
| pcpu_mem_free(chunk->alloc_map); |
| pcpu_mem_free(chunk); |
| } |
| |
| /** |
| * pcpu_chunk_populated - post-population bookkeeping |
| * @chunk: pcpu_chunk which got populated |
| * @page_start: the start page |
| * @page_end: the end page |
| * |
| * Pages in [@page_start,@page_end) have been populated to @chunk. Update |
| * the bookkeeping information accordingly. Must be called after each |
| * successful population. |
| */ |
| static void pcpu_chunk_populated(struct pcpu_chunk *chunk, int page_start, |
| int page_end) |
| { |
| int nr = page_end - page_start; |
| |
| lockdep_assert_held(&pcpu_lock); |
| |
| bitmap_set(chunk->populated, page_start, nr); |
| chunk->nr_populated += nr; |
| pcpu_nr_populated += nr; |
| |
| pcpu_update_empty_pages(chunk, nr); |
| } |
| |
| /** |
| * pcpu_chunk_depopulated - post-depopulation bookkeeping |
| * @chunk: pcpu_chunk which got depopulated |
| * @page_start: the start page |
| * @page_end: the end page |
| * |
| * Pages in [@page_start,@page_end) have been depopulated from @chunk. |
| * Update the bookkeeping information accordingly. Must be called after |
| * each successful depopulation. |
| */ |
| static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk, |
| int page_start, int page_end) |
| { |
| int nr = page_end - page_start; |
| |
| lockdep_assert_held(&pcpu_lock); |
| |
| bitmap_clear(chunk->populated, page_start, nr); |
| chunk->nr_populated -= nr; |
| pcpu_nr_populated -= nr; |
| |
| pcpu_update_empty_pages(chunk, -nr); |
| } |
| |
| /* |
| * Chunk management implementation. |
| * |
| * To allow different implementations, chunk alloc/free and |
| * [de]population are implemented in a separate file which is pulled |
| * into this file and compiled together. The following functions |
| * should be implemented. |
| * |
| * pcpu_populate_chunk - populate the specified range of a chunk |
| * pcpu_depopulate_chunk - depopulate the specified range of a chunk |
| * pcpu_post_unmap_tlb_flush - flush tlb for the specified range of a chunk |
| * pcpu_create_chunk - create a new chunk |
| * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop |
| * pcpu_addr_to_page - translate address to physical address |
| * pcpu_verify_alloc_info - check alloc_info is acceptable during init |
| */ |
| static int pcpu_populate_chunk(struct pcpu_chunk *chunk, |
| int page_start, int page_end, gfp_t gfp); |
| static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, |
| int page_start, int page_end); |
| static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk, |
| int page_start, int page_end); |
| static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp); |
| static void pcpu_destroy_chunk(struct pcpu_chunk *chunk); |
| static struct page *pcpu_addr_to_page(void *addr); |
| static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai); |
| |
| #ifdef CONFIG_NEED_PER_CPU_KM |
| #include "percpu-km.c" |
| #else |
| #include "percpu-vm.c" |
| #endif |
| |
| /** |
| * pcpu_chunk_addr_search - determine chunk containing specified address |
| * @addr: address for which the chunk needs to be determined. |
| * |
| * This is an internal function that handles all but static allocations. |
| * Static percpu address values should never be passed into the allocator. |
| * |
| * RETURNS: |
| * The address of the found chunk. |
| */ |
| static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) |
| { |
| /* is it in the dynamic region (first chunk)? */ |
| if (pcpu_addr_in_chunk(pcpu_first_chunk, addr)) |
| return pcpu_first_chunk; |
| |
| /* is it in the reserved region? */ |
| if (pcpu_addr_in_chunk(pcpu_reserved_chunk, addr)) |
| return pcpu_reserved_chunk; |
| |
| /* |
| * The address is relative to unit0 which might be unused and |
| * thus unmapped. Offset the address to the unit space of the |
| * current processor before looking it up in the vmalloc |
| * space. Note that any possible cpu id can be used here, so |
| * there's no need to worry about preemption or cpu hotplug. |
| */ |
| addr += pcpu_unit_offsets[raw_smp_processor_id()]; |
| return pcpu_get_page_chunk(pcpu_addr_to_page(addr)); |
| } |
| |
| #ifdef CONFIG_MEMCG_KMEM |
| static bool pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp, |
| struct obj_cgroup **objcgp) |
| { |
| struct obj_cgroup *objcg; |
| |
| if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT)) |
| return true; |
| |
| objcg = get_obj_cgroup_from_current(); |
| if (!objcg) |
| return true; |
| |
| if (obj_cgroup_charge(objcg, gfp, size * num_possible_cpus())) { |
| obj_cgroup_put(objcg); |
| return false; |
| } |
| |
| *objcgp = objcg; |
| return true; |
| } |
| |
| static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg, |
| struct pcpu_chunk *chunk, int off, |
| size_t size) |
| { |
| if (!objcg) |
| return; |
| |
| if (likely(chunk && chunk->obj_cgroups)) { |
| chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg; |
| |
| rcu_read_lock(); |
| mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B, |
| size * num_possible_cpus()); |
| rcu_read_unlock(); |
| } else { |
| obj_cgroup_uncharge(objcg, size * num_possible_cpus()); |
| obj_cgroup_put(objcg); |
| } |
| } |
| |
| static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size) |
| { |
| struct obj_cgroup *objcg; |
| |
| if (unlikely(!chunk->obj_cgroups)) |
| return; |
| |
| objcg = chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT]; |
| if (!objcg) |
| return; |
| chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = NULL; |
| |
| obj_cgroup_uncharge(objcg, size * num_possible_cpus()); |
| |
| rcu_read_lock(); |
| mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B, |
| -(size * num_possible_cpus())); |
| rcu_read_unlock(); |
| |
| obj_cgroup_put(objcg); |
| } |
| |
| #else /* CONFIG_MEMCG_KMEM */ |
| static bool |
| pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp, struct obj_cgroup **objcgp) |
| { |
| return true; |
| } |
| |
| static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg, |
| struct pcpu_chunk *chunk, int off, |
| size_t size) |
| { |
| } |
| |
| static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size) |
| { |
| } |
| #endif /* CONFIG_MEMCG_KMEM */ |
| |
| /** |
| * pcpu_alloc - the percpu allocator |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * @reserved: allocate from the reserved chunk if available |
| * @gfp: allocation flags |
| * |
| * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't |
| * contain %GFP_KERNEL, the allocation is atomic. If @gfp has __GFP_NOWARN |
| * then no warning will be triggered on invalid or failed allocation |
| * requests. |
| * |
| * RETURNS: |
| * Percpu pointer to the allocated area on success, NULL on failure. |
| */ |
| static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, |
| gfp_t gfp) |
| { |
| gfp_t pcpu_gfp; |
| bool is_atomic; |
| bool do_warn; |
| struct obj_cgroup *objcg = NULL; |
| static int warn_limit = 10; |
| struct pcpu_chunk *chunk, *next; |
| const char *err; |
| int slot, off, cpu, ret; |
| unsigned long flags; |
| void __percpu *ptr; |
| size_t bits, bit_align; |
| |
| gfp = current_gfp_context(gfp); |
| /* whitelisted flags that can be passed to the backing allocators */ |
| pcpu_gfp = gfp & (GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN); |
| is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL; |
| do_warn = !(gfp & __GFP_NOWARN); |
| |
| /* |
| * There is now a minimum allocation size of PCPU_MIN_ALLOC_SIZE, |
| * therefore alignment must be a minimum of that many bytes. |
| * An allocation may have internal fragmentation from rounding up |
| * of up to PCPU_MIN_ALLOC_SIZE - 1 bytes. |
| */ |
| if (unlikely(align < PCPU_MIN_ALLOC_SIZE)) |
| align = PCPU_MIN_ALLOC_SIZE; |
| |
| size = ALIGN(size, PCPU_MIN_ALLOC_SIZE); |
| bits = size >> PCPU_MIN_ALLOC_SHIFT; |
| bit_align = align >> PCPU_MIN_ALLOC_SHIFT; |
| |
| if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE || |
| !is_power_of_2(align))) { |
| WARN(do_warn, "illegal size (%zu) or align (%zu) for percpu allocation\n", |
| size, align); |
| return NULL; |
| } |
| |
| if (unlikely(!pcpu_memcg_pre_alloc_hook(size, gfp, &objcg))) |
| return NULL; |
| |
| if (!is_atomic) { |
| /* |
| * pcpu_balance_workfn() allocates memory under this mutex, |
| * and it may wait for memory reclaim. Allow current task |
| * to become OOM victim, in case of memory pressure. |
| */ |
| if (gfp & __GFP_NOFAIL) { |
| mutex_lock(&pcpu_alloc_mutex); |
| } else if (mutex_lock_killable(&pcpu_alloc_mutex)) { |
| pcpu_memcg_post_alloc_hook(objcg, NULL, 0, size); |
| return NULL; |
| } |
| } |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| |
| /* serve reserved allocations from the reserved chunk if available */ |
| if (reserved && pcpu_reserved_chunk) { |
| chunk = pcpu_reserved_chunk; |
| |
| off = pcpu_find_block_fit(chunk, bits, bit_align, is_atomic); |
| if (off < 0) { |
| err = "alloc from reserved chunk failed"; |
| goto fail_unlock; |
| } |
| |
| off = pcpu_alloc_area(chunk, bits, bit_align, off); |
| if (off >= 0) |
| goto area_found; |
| |
| err = "alloc from reserved chunk failed"; |
| goto fail_unlock; |
| } |
| |
| restart: |
| /* search through normal chunks */ |
| for (slot = pcpu_size_to_slot(size); slot <= pcpu_free_slot; slot++) { |
| list_for_each_entry_safe(chunk, next, &pcpu_chunk_lists[slot], |
| list) { |
| off = pcpu_find_block_fit(chunk, bits, bit_align, |
| is_atomic); |
| if (off < 0) { |
| if (slot < PCPU_SLOT_FAIL_THRESHOLD) |
| pcpu_chunk_move(chunk, 0); |
| continue; |
| } |
| |
| off = pcpu_alloc_area(chunk, bits, bit_align, off); |
| if (off >= 0) { |
| pcpu_reintegrate_chunk(chunk); |
| goto area_found; |
| } |
| } |
| } |
| |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| |
| /* |
| * No space left. Create a new chunk. We don't want multiple |
| * tasks to create chunks simultaneously. Serialize and create iff |
| * there's still no empty chunk after grabbing the mutex. |
| */ |
| if (is_atomic) { |
| err = "atomic alloc failed, no space left"; |
| goto fail; |
| } |
| |
| if (list_empty(&pcpu_chunk_lists[pcpu_free_slot])) { |
| chunk = pcpu_create_chunk(pcpu_gfp); |
| if (!chunk) { |
| err = "failed to allocate new chunk"; |
| goto fail; |
| } |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| pcpu_chunk_relocate(chunk, -1); |
| } else { |
| spin_lock_irqsave(&pcpu_lock, flags); |
| } |
| |
| goto restart; |
| |
| area_found: |
| pcpu_stats_area_alloc(chunk, size); |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| |
| /* populate if not all pages are already there */ |
| if (!is_atomic) { |
| unsigned int page_start, page_end, rs, re; |
| |
| page_start = PFN_DOWN(off); |
| page_end = PFN_UP(off + size); |
| |
| bitmap_for_each_clear_region(chunk->populated, rs, re, |
| page_start, page_end) { |
| WARN_ON(chunk->immutable); |
| |
| ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp); |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| if (ret) { |
| pcpu_free_area(chunk, off); |
| err = "failed to populate"; |
| goto fail_unlock; |
| } |
| pcpu_chunk_populated(chunk, rs, re); |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| } |
| |
| mutex_unlock(&pcpu_alloc_mutex); |
| } |
| |
| if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) |
| pcpu_schedule_balance_work(); |
| |
| /* clear the areas and return address relative to base address */ |
| for_each_possible_cpu(cpu) |
| memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size); |
| |
| ptr = __addr_to_pcpu_ptr(chunk->base_addr + off); |
| kmemleak_alloc_percpu(ptr, size, gfp); |
| |
| trace_percpu_alloc_percpu(reserved, is_atomic, size, align, |
| chunk->base_addr, off, ptr); |
| |
| pcpu_memcg_post_alloc_hook(objcg, chunk, off, size); |
| |
| return ptr; |
| |
| fail_unlock: |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| fail: |
| trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align); |
| |
| if (!is_atomic && do_warn && warn_limit) { |
| pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n", |
| size, align, is_atomic, err); |
| dump_stack(); |
| if (!--warn_limit) |
| pr_info("limit reached, disable warning\n"); |
| } |
| if (is_atomic) { |
| /* see the flag handling in pcpu_balance_workfn() */ |
| pcpu_atomic_alloc_failed = true; |
| pcpu_schedule_balance_work(); |
| } else { |
| mutex_unlock(&pcpu_alloc_mutex); |
| } |
| |
| pcpu_memcg_post_alloc_hook(objcg, NULL, 0, size); |
| |
| return NULL; |
| } |
| |
| /** |
| * __alloc_percpu_gfp - allocate dynamic percpu area |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * @gfp: allocation flags |
| * |
| * Allocate zero-filled percpu area of @size bytes aligned at @align. If |
| * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can |
| * be called from any context but is a lot more likely to fail. If @gfp |
| * has __GFP_NOWARN then no warning will be triggered on invalid or failed |
| * allocation requests. |
| * |
| * RETURNS: |
| * Percpu pointer to the allocated area on success, NULL on failure. |
| */ |
| void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) |
| { |
| return pcpu_alloc(size, align, false, gfp); |
| } |
| EXPORT_SYMBOL_GPL(__alloc_percpu_gfp); |
| |
| /** |
| * __alloc_percpu - allocate dynamic percpu area |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * |
| * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL). |
| */ |
| void __percpu *__alloc_percpu(size_t size, size_t align) |
| { |
| return pcpu_alloc(size, align, false, GFP_KERNEL); |
| } |
| EXPORT_SYMBOL_GPL(__alloc_percpu); |
| |
| /** |
| * __alloc_reserved_percpu - allocate reserved percpu area |
| * @size: size of area to allocate in bytes |
| * @align: alignment of area (max PAGE_SIZE) |
| * |
| * Allocate zero-filled percpu area of @size bytes aligned at @align |
| * from reserved percpu area if arch has set it up; otherwise, |
| * allocation is served from the same dynamic area. Might sleep. |
| * Might trigger writeouts. |
| * |
| * CONTEXT: |
| * Does GFP_KERNEL allocation. |
| * |
| * RETURNS: |
| * Percpu pointer to the allocated area on success, NULL on failure. |
| */ |
| void __percpu *__alloc_reserved_percpu(size_t size, size_t align) |
| { |
| return pcpu_alloc(size, align, true, GFP_KERNEL); |
| } |
| |
| /** |
| * pcpu_balance_free - manage the amount of free chunks |
| * @empty_only: free chunks only if there are no populated pages |
| * |
| * If empty_only is %false, reclaim all fully free chunks regardless of the |
| * number of populated pages. Otherwise, only reclaim chunks that have no |
| * populated pages. |
| * |
| * CONTEXT: |
| * pcpu_lock (can be dropped temporarily) |
| */ |
| static void pcpu_balance_free(bool empty_only) |
| { |
| LIST_HEAD(to_free); |
| struct list_head *free_head = &pcpu_chunk_lists[pcpu_free_slot]; |
| struct pcpu_chunk *chunk, *next; |
| |
| lockdep_assert_held(&pcpu_lock); |
| |
| /* |
| * There's no reason to keep around multiple unused chunks and VM |
| * areas can be scarce. Destroy all free chunks except for one. |
| */ |
| list_for_each_entry_safe(chunk, next, free_head, list) { |
| WARN_ON(chunk->immutable); |
| |
| /* spare the first one */ |
| if (chunk == list_first_entry(free_head, struct pcpu_chunk, list)) |
| continue; |
| |
| if (!empty_only || chunk->nr_empty_pop_pages == 0) |
| list_move(&chunk->list, &to_free); |
| } |
| |
| if (list_empty(&to_free)) |
| return; |
| |
| spin_unlock_irq(&pcpu_lock); |
| list_for_each_entry_safe(chunk, next, &to_free, list) { |
| unsigned int rs, re; |
| |
| bitmap_for_each_set_region(chunk->populated, rs, re, 0, |
| chunk->nr_pages) { |
| pcpu_depopulate_chunk(chunk, rs, re); |
| spin_lock_irq(&pcpu_lock); |
| pcpu_chunk_depopulated(chunk, rs, re); |
| spin_unlock_irq(&pcpu_lock); |
| } |
| pcpu_destroy_chunk(chunk); |
| cond_resched(); |
| } |
| spin_lock_irq(&pcpu_lock); |
| } |
| |
| /** |
| * pcpu_balance_populated - manage the amount of populated pages |
| * |
| * Maintain a certain amount of populated pages to satisfy atomic allocations. |
| * It is possible that this is called when physical memory is scarce causing |
| * OOM killer to be triggered. We should avoid doing so until an actual |
| * allocation causes the failure as it is possible that requests can be |
| * serviced from already backed regions. |
| * |
| * CONTEXT: |
| * pcpu_lock (can be dropped temporarily) |
| */ |
| static void pcpu_balance_populated(void) |
| { |
| /* gfp flags passed to underlying allocators */ |
| const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN; |
| struct pcpu_chunk *chunk; |
| int slot, nr_to_pop, ret; |
| |
| lockdep_assert_held(&pcpu_lock); |
| |
| /* |
| * Ensure there are certain number of free populated pages for |
| * atomic allocs. Fill up from the most packed so that atomic |
| * allocs don't increase fragmentation. If atomic allocation |
| * failed previously, always populate the maximum amount. This |
| * should prevent atomic allocs larger than PAGE_SIZE from keeping |
| * failing indefinitely; however, large atomic allocs are not |
| * something we support properly and can be highly unreliable and |
| * inefficient. |
| */ |
| retry_pop: |
| if (pcpu_atomic_alloc_failed) { |
| nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH; |
| /* best effort anyway, don't worry about synchronization */ |
| pcpu_atomic_alloc_failed = false; |
| } else { |
| nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH - |
| pcpu_nr_empty_pop_pages, |
| 0, PCPU_EMPTY_POP_PAGES_HIGH); |
| } |
| |
| for (slot = pcpu_size_to_slot(PAGE_SIZE); slot <= pcpu_free_slot; slot++) { |
| unsigned int nr_unpop = 0, rs, re; |
| |
| if (!nr_to_pop) |
| break; |
| |
| list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) { |
| nr_unpop = chunk->nr_pages - chunk->nr_populated; |
| if (nr_unpop) |
| break; |
| } |
| |
| if (!nr_unpop) |
| continue; |
| |
| /* @chunk can't go away while pcpu_alloc_mutex is held */ |
| bitmap_for_each_clear_region(chunk->populated, rs, re, 0, |
| chunk->nr_pages) { |
| int nr = min_t(int, re - rs, nr_to_pop); |
| |
| spin_unlock_irq(&pcpu_lock); |
| ret = pcpu_populate_chunk(chunk, rs, rs + nr, gfp); |
| cond_resched(); |
| spin_lock_irq(&pcpu_lock); |
| if (!ret) { |
| nr_to_pop -= nr; |
| pcpu_chunk_populated(chunk, rs, rs + nr); |
| } else { |
| nr_to_pop = 0; |
| } |
| |
| if (!nr_to_pop) |
| break; |
| } |
| } |
| |
| if (nr_to_pop) { |
| /* ran out of chunks to populate, create a new one and retry */ |
| spin_unlock_irq(&pcpu_lock); |
| chunk = pcpu_create_chunk(gfp); |
| cond_resched(); |
| spin_lock_irq(&pcpu_lock); |
| if (chunk) { |
| pcpu_chunk_relocate(chunk, -1); |
| goto retry_pop; |
| } |
| } |
| } |
| |
| /** |
| * pcpu_reclaim_populated - scan over to_depopulate chunks and free empty pages |
| * |
| * Scan over chunks in the depopulate list and try to release unused populated |
| * pages back to the system. Depopulated chunks are sidelined to prevent |
| * repopulating these pages unless required. Fully free chunks are reintegrated |
| * and freed accordingly (1 is kept around). If we drop below the empty |
| * populated pages threshold, reintegrate the chunk if it has empty free pages. |
| * Each chunk is scanned in the reverse order to keep populated pages close to |
| * the beginning of the chunk. |
| * |
| * CONTEXT: |
| * pcpu_lock (can be dropped temporarily) |
| * |
| */ |
| static void pcpu_reclaim_populated(void) |
| { |
| struct pcpu_chunk *chunk; |
| struct pcpu_block_md *block; |
| int freed_page_start, freed_page_end; |
| int i, end; |
| bool reintegrate; |
| |
| lockdep_assert_held(&pcpu_lock); |
| |
| /* |
| * Once a chunk is isolated to the to_depopulate list, the chunk is no |
| * longer discoverable to allocations whom may populate pages. The only |
| * other accessor is the free path which only returns area back to the |
| * allocator not touching the populated bitmap. |
| */ |
| while (!list_empty(&pcpu_chunk_lists[pcpu_to_depopulate_slot])) { |
| chunk = list_first_entry(&pcpu_chunk_lists[pcpu_to_depopulate_slot], |
| struct pcpu_chunk, list); |
| WARN_ON(chunk->immutable); |
| |
| /* |
| * Scan chunk's pages in the reverse order to keep populated |
| * pages close to the beginning of the chunk. |
| */ |
| freed_page_start = chunk->nr_pages; |
| freed_page_end = 0; |
| reintegrate = false; |
| for (i = chunk->nr_pages - 1, end = -1; i >= 0; i--) { |
| /* no more work to do */ |
| if (chunk->nr_empty_pop_pages == 0) |
| break; |
| |
| /* reintegrate chunk to prevent atomic alloc failures */ |
| if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_HIGH) { |
| reintegrate = true; |
| goto end_chunk; |
| } |
| |
| /* |
| * If the page is empty and populated, start or |
| * extend the (i, end) range. If i == 0, decrease |
| * i and perform the depopulation to cover the last |
| * (first) page in the chunk. |
| */ |
| block = chunk->md_blocks + i; |
| if (block->contig_hint == PCPU_BITMAP_BLOCK_BITS && |
| test_bit(i, chunk->populated)) { |
| if (end == -1) |
| end = i; |
| if (i > 0) |
| continue; |
| i--; |
| } |
| |
| /* depopulate if there is an active range */ |
| if (end == -1) |
| continue; |
| |
| spin_unlock_irq(&pcpu_lock); |
| pcpu_depopulate_chunk(chunk, i + 1, end + 1); |
| cond_resched(); |
| spin_lock_irq(&pcpu_lock); |
| |
| pcpu_chunk_depopulated(chunk, i + 1, end + 1); |
| freed_page_start = min(freed_page_start, i + 1); |
| freed_page_end = max(freed_page_end, end + 1); |
| |
| /* reset the range and continue */ |
| end = -1; |
| } |
| |
| end_chunk: |
| /* batch tlb flush per chunk to amortize cost */ |
| if (freed_page_start < freed_page_end) { |
| spin_unlock_irq(&pcpu_lock); |
| pcpu_post_unmap_tlb_flush(chunk, |
| freed_page_start, |
| freed_page_end); |
| cond_resched(); |
| spin_lock_irq(&pcpu_lock); |
| } |
| |
| if (reintegrate || chunk->free_bytes == pcpu_unit_size) |
| pcpu_reintegrate_chunk(chunk); |
| else |
| list_move_tail(&chunk->list, |
| &pcpu_chunk_lists[pcpu_sidelined_slot]); |
| } |
| } |
| |
| /** |
| * pcpu_balance_workfn - manage the amount of free chunks and populated pages |
| * @work: unused |
| * |
| * For each chunk type, manage the number of fully free chunks and the number of |
| * populated pages. An important thing to consider is when pages are freed and |
| * how they contribute to the global counts. |
| */ |
| static void pcpu_balance_workfn(struct work_struct *work) |
| { |
| /* |
| * pcpu_balance_free() is called twice because the first time we may |
| * trim pages in the active pcpu_nr_empty_pop_pages which may cause us |
| * to grow other chunks. This then gives pcpu_reclaim_populated() time |
| * to move fully free chunks to the active list to be freed if |
| * appropriate. |
| */ |
| mutex_lock(&pcpu_alloc_mutex); |
| spin_lock_irq(&pcpu_lock); |
| |
| pcpu_balance_free(false); |
| pcpu_reclaim_populated(); |
| pcpu_balance_populated(); |
| pcpu_balance_free(true); |
| |
| spin_unlock_irq(&pcpu_lock); |
| mutex_unlock(&pcpu_alloc_mutex); |
| } |
| |
| /** |
| * free_percpu - free percpu area |
| * @ptr: pointer to area to free |
| * |
| * Free percpu area @ptr. |
| * |
| * CONTEXT: |
| * Can be called from atomic context. |
| */ |
| void free_percpu(void __percpu *ptr) |
| { |
| void *addr; |
| struct pcpu_chunk *chunk; |
| unsigned long flags; |
| int size, off; |
| bool need_balance = false; |
| |
| if (!ptr) |
| return; |
| |
| kmemleak_free_percpu(ptr); |
| |
| addr = __pcpu_ptr_to_addr(ptr); |
| |
| spin_lock_irqsave(&pcpu_lock, flags); |
| |
| chunk = pcpu_chunk_addr_search(addr); |
| off = addr - chunk->base_addr; |
| |
| size = pcpu_free_area(chunk, off); |
| |
| pcpu_memcg_free_hook(chunk, off, size); |
| |
| /* |
| * If there are more than one fully free chunks, wake up grim reaper. |
| * If the chunk is isolated, it may be in the process of being |
| * reclaimed. Let reclaim manage cleaning up of that chunk. |
| */ |
| if (!chunk->isolated && chunk->free_bytes == pcpu_unit_size) { |
| struct pcpu_chunk *pos; |
| |
| list_for_each_entry(pos, &pcpu_chunk_lists[pcpu_free_slot], list) |
| if (pos != chunk) { |
| need_balance = true; |
| break; |
| } |
| } else if (pcpu_should_reclaim_chunk(chunk)) { |
| pcpu_isolate_chunk(chunk); |
| need_balance = true; |
| } |
| |
| trace_percpu_free_percpu(chunk->base_addr, off, ptr); |
| |
| spin_unlock_irqrestore(&pcpu_lock, flags); |
| |
| if (need_balance) |
| pcpu_schedule_balance_work(); |
| } |
| EXPORT_SYMBOL_GPL(free_percpu); |
| |
| bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr) |
| { |
| #ifdef CONFIG_SMP |
| const size_t static_size = __per_cpu_end - __per_cpu_start; |
| void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); |
| unsigned int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| void *start = per_cpu_ptr(base, cpu); |
| void *va = (void *)addr; |
| |
| if (va >= start && va < start + static_size) { |
| if (can_addr) { |
| *can_addr = (unsigned long) (va - start); |
| *can_addr += (unsigned long) |
| per_cpu_ptr(base, get_boot_cpu_id()); |
| } |
| return true; |
| } |
| } |
| #endif |
| /* on UP, can't distinguish from other static vars, always false */ |
| return false; |
| } |
| |
| /** |
| * is_kernel_percpu_address - test whether address is from static percpu area |
| * @addr: address to test |
| * |
| * Test whether @addr belongs to in-kernel static percpu area. Module |
| * static percpu areas are not considered. For those, use |
| * is_module_percpu_address(). |
| * |
| * RETURNS: |
| * %true if @addr is from in-kernel static percpu area, %false otherwise. |
| */ |
| bool is_kernel_percpu_address(unsigned long addr) |
| { |
| return __is_kernel_percpu_address(addr, NULL); |
| } |
| |
| /** |
| * per_cpu_ptr_to_phys - convert translated percpu address to physical address |
| * @addr: the address to be converted to physical address |
| * |
| * Given @addr which is dereferenceable address obtained via one of |
| * percpu access macros, this function translates it into its physical |
| * address. The caller is responsible for ensuring @addr stays valid |
| * until this function finishes. |
| * |
| * percpu allocator has special setup for the first chunk, which currently |
| * supports either embedding in linear address space or vmalloc mapping, |
| * and, from the second one, the backing allocator (currently either vm or |
| * km) provides translation. |
| * |
| * The addr can be translated simply without checking if it falls into the |
| * first chunk. But the current code reflects better how percpu allocator |
| * actually works, and the verification can discover both bugs in percpu |
| * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current |
| * code. |
| * |
| * RETURNS: |
| * The physical address for @addr. |
| */ |
| phys_addr_t per_cpu_ptr_to_phys(void *addr) |
| { |
| void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); |
| bool in_first_chunk = false; |
| unsigned long first_low, first_high; |
| unsigned int cpu; |
| |
| /* |
| * The following test on unit_low/high isn't strictly |
| * necessary but will speed up lookups of addresses which |
| * aren't in the first chunk. |
| * |
| * The address check is against full chunk sizes. pcpu_base_addr |
| * points to the beginning of the first chunk including the |
| * static region. Assumes good intent as the first chunk may |
| * not be full (ie. < pcpu_unit_pages in size). |
| */ |
| first_low = (unsigned long)pcpu_base_addr + |
| pcpu_unit_page_offset(pcpu_low_unit_cpu, 0); |
| first_high = (unsigned long)pcpu_base_addr + |
| pcpu_unit_page_offset(pcpu_high_unit_cpu, pcpu_unit_pages); |
| if ((unsigned long)addr >= first_low && |
| (unsigned long)addr < first_high) { |
| for_each_possible_cpu(cpu) { |
| void *start = per_cpu_ptr(base, cpu); |
| |
| if (addr >= start && addr < start + pcpu_unit_size) { |
| in_first_chunk = true; |
| break; |
| } |
| } |
| } |
| |
| if (in_first_chunk) { |
| if (!is_vmalloc_addr(addr)) |
| return __pa(addr); |
| else |
| return page_to_phys(vmalloc_to_page(addr)) + |
| offset_in_page(addr); |
| } else |
| return page_to_phys(pcpu_addr_to_page(addr)) + |
| offset_in_page(addr); |
| } |
| EXPORT_SYMBOL_GPL(per_cpu_ptr_to_phys); |
| |
| /** |
| * pcpu_alloc_alloc_info - allocate percpu allocation info |
| * @nr_groups: the number of groups |
| * @nr_units: the number of units |
| * |
| * Allocate ai which is large enough for @nr_groups groups containing |
| * @nr_units units. The returned ai's groups[0].cpu_map points to the |
| * cpu_map array which is long enough for @nr_units and filled with |
| * NR_CPUS. It's the caller's responsibility to initialize cpu_map |
| * pointer of other groups. |
| * |
| * RETURNS: |
| * Pointer to the allocated pcpu_alloc_info on success, NULL on |
| * failure. |
| */ |
| struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups, |
| int nr_units) |
| { |
| struct pcpu_alloc_info *ai; |
| size_t base_size, ai_size; |
| void *ptr; |
| int unit; |
| |
| base_size = ALIGN(struct_size(ai, groups, nr_groups), |
| __alignof__(ai->groups[0].cpu_map[0])); |
| ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]); |
| |
| ptr = memblock_alloc(PFN_ALIGN(ai_size), PAGE_SIZE); |
| if (!ptr) |
| return NULL; |
| ai = ptr; |
| ptr += base_size; |
| |
| ai->groups[0].cpu_map = ptr; |
| |
| for (unit = 0; unit < nr_units; unit++) |
| ai->groups[0].cpu_map[unit] = NR_CPUS; |
| |
| ai->nr_groups = nr_groups; |
| ai->__ai_size = PFN_ALIGN(ai_size); |
| |
| return ai; |
| } |
| |
| /** |
| * pcpu_free_alloc_info - free percpu allocation info |
| * @ai: pcpu_alloc_info to free |
| * |
| * Free @ai which was allocated by pcpu_alloc_alloc_info(). |
| */ |
| void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai) |
| { |
| memblock_free_early(__pa(ai), ai->__ai_size); |
| } |
| |
| /** |
| * pcpu_dump_alloc_info - print out information about pcpu_alloc_info |
| * @lvl: loglevel |
| * @ai: allocation info to dump |
| * |
| * Print out information about @ai using loglevel @lvl. |
| */ |
| static void pcpu_dump_alloc_info(const char *lvl, |
| const struct pcpu_alloc_info *ai) |
| { |
| int group_width = 1, cpu_width = 1, width; |
| char empty_str[] = "--------"; |
| int alloc = 0, alloc_end = 0; |
| int group, v; |
| int upa, apl; /* units per alloc, allocs per line */ |
| |
| v = ai->nr_groups; |
| while (v /= 10) |
| group_width++; |
| |
| v = num_possible_cpus(); |
| while (v /= 10) |
| cpu_width++; |
| empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0'; |
| |
| upa = ai->alloc_size / ai->unit_size; |
| width = upa * (cpu_width + 1) + group_width + 3; |
| apl = rounddown_pow_of_two(max(60 / width, 1)); |
| |
| printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu", |
| lvl, ai->static_size, ai->reserved_size, ai->dyn_size, |
| ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size); |
| |
| for (group = 0; group < ai->nr_groups; group++) { |
| const struct pcpu_group_info *gi = &ai->groups[group]; |
| int unit = 0, unit_end = 0; |
| |
| BUG_ON(gi->nr_units % upa); |
| for (alloc_end += gi->nr_units / upa; |
| alloc < alloc_end; alloc++) { |
| if (!(alloc % apl)) { |
| pr_cont("\n"); |
| printk("%spcpu-alloc: ", lvl); |
| } |
| pr_cont("[%0*d] ", group_width, group); |
| |
| for (unit_end += upa; unit < unit_end; unit++) |
| if (gi->cpu_map[unit] != NR_CPUS) |
| pr_cont("%0*d ", |
| cpu_width, gi->cpu_map[unit]); |
| else |
| pr_cont("%s ", empty_str); |
| } |
| } |
| pr_cont("\n"); |
| } |
| |
| /** |
| * pcpu_setup_first_chunk - initialize the first percpu chunk |
| * @ai: pcpu_alloc_info describing how to percpu area is shaped |
| * @base_addr: mapped address |
| * |
| * Initialize the first percpu chunk which contains the kernel static |
| * percpu area. This function is to be called from arch percpu area |
| * setup path. |
| * |
| * @ai contains all information necessary to initialize the first |
| * chunk and prime the dynamic percpu allocator. |
| * |
| * @ai->static_size is the size of static percpu area. |
| * |
| * @ai->reserved_size, if non-zero, specifies the amount of bytes to |
| * reserve after the static area in the first chunk. This reserves |
| * the first chunk such that it's available only through reserved |
| * percpu allocation. This is primarily used to serve module percpu |
| * static areas on architectures where the addressing model has |
| * limited offset range for symbol relocations to guarantee module |
| * percpu symbols fall inside the relocatable range. |
| * |
| * @ai->dyn_size determines the number of bytes available for dynamic |
| * allocation in the first chunk. The area between @ai->static_size + |
| * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused. |
| * |
| * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE |
| * and equal to or larger than @ai->static_size + @ai->reserved_size + |
| * @ai->dyn_size. |
| * |
| * @ai->atom_size is the allocation atom size and used as alignment |
| * for vm areas. |
| * |
| * @ai->alloc_size is the allocation size and always multiple of |
| * @ai->atom_size. This is larger than @ai->atom_size if |
| * @ai->unit_size is larger than @ai->atom_size. |
| * |
| * @ai->nr_groups and @ai->groups describe virtual memory layout of |
| * percpu areas. Units which should be colocated are put into the |
| * same group. Dynamic VM areas will be allocated according to these |
| * groupings. If @ai->nr_groups is zero, a single group containing |
| * all units is assumed. |
| * |
| * The caller should have mapped the first chunk at @base_addr and |
| * copied static data to each unit. |
| * |
| * The first chunk will always contain a static and a dynamic region. |
| * However, the static region is not managed by any chunk. If the first |
| * chunk also contains a reserved region, it is served by two chunks - |
| * one for the reserved region and one for the dynamic region. They |
| * share the same vm, but use offset regions in the area allocation map. |
| * The chunk serving the dynamic region is circulated in the chunk slots |
| * and available for dynamic allocation like any other chunk. |
| */ |
| void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, |
| void *base_addr) |
| { |
| size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; |
| size_t static_size, dyn_size; |
| struct pcpu_chunk *chunk; |
| unsigned long *group_offsets; |
| size_t *group_sizes; |
| unsigned long *unit_off; |
| unsigned int cpu; |
| int *unit_map; |
| int group, unit, i; |
| int map_size; |
| unsigned long tmp_addr; |
| size_t alloc_size; |
| |
| #define PCPU_SETUP_BUG_ON(cond) do { \ |
| if (unlikely(cond)) { \ |
| pr_emerg("failed to initialize, %s\n", #cond); \ |
| pr_emerg("cpu_possible_mask=%*pb\n", \ |
| cpumask_pr_args(cpu_possible_mask)); \ |
| pcpu_dump_alloc_info(KERN_EMERG, ai); \ |
| BUG(); \ |
| } \ |
| } while (0) |
| |
| /* sanity checks */ |
| PCPU_SETUP_BUG_ON(ai->nr_groups <= 0); |
| #ifdef CONFIG_SMP |
| PCPU_SETUP_BUG_ON(!ai->static_size); |
| PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start)); |
| #endif |
| PCPU_SETUP_BUG_ON(!base_addr); |
| PCPU_SETUP_BUG_ON(offset_in_page(base_addr)); |
| PCPU_SETUP_BUG_ON(ai->unit_size < size_sum); |
| PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size)); |
| PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE); |
| PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->unit_size, PCPU_BITMAP_BLOCK_SIZE)); |
| PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE); |
| PCPU_SETUP_BUG_ON(!ai->dyn_size); |
| PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->reserved_size, PCPU_MIN_ALLOC_SIZE)); |
| PCPU_SETUP_BUG_ON(!(IS_ALIGNED(PCPU_BITMAP_BLOCK_SIZE, PAGE_SIZE) || |
| IS_ALIGNED(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE))); |
| PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0); |
| |
| /* process group information and build config tables accordingly */ |
| alloc_size = ai->nr_groups * sizeof(group_offsets[0]); |
| group_offsets = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!group_offsets) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| alloc_size = ai->nr_groups * sizeof(group_sizes[0]); |
| group_sizes = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!group_sizes) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| alloc_size = nr_cpu_ids * sizeof(unit_map[0]); |
| unit_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!unit_map) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| alloc_size = nr_cpu_ids * sizeof(unit_off[0]); |
| unit_off = memblock_alloc(alloc_size, SMP_CACHE_BYTES); |
| if (!unit_off) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| alloc_size); |
| |
| for (cpu = 0; cpu < nr_cpu_ids; cpu++) |
| unit_map[cpu] = UINT_MAX; |
| |
| pcpu_low_unit_cpu = NR_CPUS; |
| pcpu_high_unit_cpu = NR_CPUS; |
| |
| for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) { |
| const struct pcpu_group_info *gi = &ai->groups[group]; |
| |
| group_offsets[group] = gi->base_offset; |
| group_sizes[group] = gi->nr_units * ai->unit_size; |
| |
| for (i = 0; i < gi->nr_units; i++) { |
| cpu = gi->cpu_map[i]; |
| if (cpu == NR_CPUS) |
| continue; |
| |
| PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids); |
| PCPU_SETUP_BUG_ON(!cpu_possible(cpu)); |
| PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX); |
| |
| unit_map[cpu] = unit + i; |
| unit_off[cpu] = gi->base_offset + i * ai->unit_size; |
| |
| /* determine low/high unit_cpu */ |
| if (pcpu_low_unit_cpu == NR_CPUS || |
| unit_off[cpu] < unit_off[pcpu_low_unit_cpu]) |
| pcpu_low_unit_cpu = cpu; |
| if (pcpu_high_unit_cpu == NR_CPUS || |
| unit_off[cpu] > unit_off[pcpu_high_unit_cpu]) |
| pcpu_high_unit_cpu = cpu; |
| } |
| } |
| pcpu_nr_units = unit; |
| |
| for_each_possible_cpu(cpu) |
| PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX); |
| |
| /* we're done parsing the input, undefine BUG macro and dump config */ |
| #undef PCPU_SETUP_BUG_ON |
| pcpu_dump_alloc_info(KERN_DEBUG, ai); |
| |
| pcpu_nr_groups = ai->nr_groups; |
| pcpu_group_offsets = group_offsets; |
| pcpu_group_sizes = group_sizes; |
| pcpu_unit_map = unit_map; |
| pcpu_unit_offsets = unit_off; |
| |
| /* determine basic parameters */ |
| pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; |
| pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; |
| pcpu_atom_size = ai->atom_size; |
| pcpu_chunk_struct_size = struct_size(chunk, populated, |
| BITS_TO_LONGS(pcpu_unit_pages)); |
| |
| pcpu_stats_save_ai(ai); |
| |
| /* |
| * Allocate chunk slots. The slots after the active slots are: |
| * sidelined_slot - isolated, depopulated chunks |
| * free_slot - fully free chunks |
| * to_depopulate_slot - isolated, chunks to depopulate |
| */ |
| pcpu_sidelined_slot = __pcpu_size_to_slot(pcpu_unit_size) + 1; |
| pcpu_free_slot = pcpu_sidelined_slot + 1; |
| pcpu_to_depopulate_slot = pcpu_free_slot + 1; |
| pcpu_nr_slots = pcpu_to_depopulate_slot + 1; |
| pcpu_chunk_lists = memblock_alloc(pcpu_nr_slots * |
| sizeof(pcpu_chunk_lists[0]), |
| SMP_CACHE_BYTES); |
| if (!pcpu_chunk_lists) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| pcpu_nr_slots * sizeof(pcpu_chunk_lists[0])); |
| |
| for (i = 0; i < pcpu_nr_slots; i++) |
| INIT_LIST_HEAD(&pcpu_chunk_lists[i]); |
| |
| /* |
| * The end of the static region needs to be aligned with the |
| * minimum allocation size as this offsets the reserved and |
| * dynamic region. The first chunk ends page aligned by |
| * expanding the dynamic region, therefore the dynamic region |
| * can be shrunk to compensate while still staying above the |
| * configured sizes. |
| */ |
| static_size = ALIGN(ai->static_size, PCPU_MIN_ALLOC_SIZE); |
| dyn_size = ai->dyn_size - (static_size - ai->static_size); |
| |
| /* |
| * Initialize first chunk. |
| * If the reserved_size is non-zero, this initializes the reserved |
| * chunk. If the reserved_size is zero, the reserved chunk is NULL |
| * and the dynamic region is initialized here. The first chunk, |
| * pcpu_first_chunk, will always point to the chunk that serves |
| * the dynamic region. |
| */ |
| tmp_addr = (unsigned long)base_addr + static_size; |
| map_size = ai->reserved_size ?: dyn_size; |
| chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); |
| |
| /* init dynamic chunk if necessary */ |
| if (ai->reserved_size) { |
| pcpu_reserved_chunk = chunk; |
| |
| tmp_addr = (unsigned long)base_addr + static_size + |
| ai->reserved_size; |
| map_size = dyn_size; |
| chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); |
| } |
| |
| /* link the first chunk in */ |
| pcpu_first_chunk = chunk; |
| pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages; |
| pcpu_chunk_relocate(pcpu_first_chunk, -1); |
| |
| /* include all regions of the first chunk */ |
| pcpu_nr_populated += PFN_DOWN(size_sum); |
| |
| pcpu_stats_chunk_alloc(); |
| trace_percpu_create_chunk(base_addr); |
| |
| /* we're done */ |
| pcpu_base_addr = base_addr; |
| } |
| |
| #ifdef CONFIG_SMP |
| |
| const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = { |
| [PCPU_FC_AUTO] = "auto", |
| [PCPU_FC_EMBED] = "embed", |
| [PCPU_FC_PAGE] = "page", |
| }; |
| |
| enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO; |
| |
| static int __init percpu_alloc_setup(char *str) |
| { |
| if (!str) |
| return -EINVAL; |
| |
| if (0) |
| /* nada */; |
| #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK |
| else if (!strcmp(str, "embed")) |
| pcpu_chosen_fc = PCPU_FC_EMBED; |
| #endif |
| #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
| else if (!strcmp(str, "page")) |
| pcpu_chosen_fc = PCPU_FC_PAGE; |
| #endif |
| else |
| pr_warn("unknown allocator %s specified\n", str); |
| |
| return 0; |
| } |
| early_param("percpu_alloc", percpu_alloc_setup); |
| |
| /* |
| * pcpu_embed_first_chunk() is used by the generic percpu setup. |
| * Build it if needed by the arch config or the generic setup is going |
| * to be used. |
| */ |
| #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \ |
| !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) |
| #define BUILD_EMBED_FIRST_CHUNK |
| #endif |
| |
| /* build pcpu_page_first_chunk() iff needed by the arch config */ |
| #if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK) |
| #define BUILD_PAGE_FIRST_CHUNK |
| #endif |
| |
| /* pcpu_build_alloc_info() is used by both embed and page first chunk */ |
| #if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK) |
| /** |
| * pcpu_build_alloc_info - build alloc_info considering distances between CPUs |
| * @reserved_size: the size of reserved percpu area in bytes |
| * @dyn_size: minimum free size for dynamic allocation in bytes |
| * @atom_size: allocation atom size |
| * @cpu_distance_fn: callback to determine distance between cpus, optional |
| * |
| * This function determines grouping of units, their mappings to cpus |
| * and other parameters considering needed percpu size, allocation |
| * atom size and distances between CPUs. |
| * |
| * Groups are always multiples of atom size and CPUs which are of |
| * LOCAL_DISTANCE both ways are grouped together and share space for |
| * units in the same group. The returned configuration is guaranteed |
| * to have CPUs on different nodes on different groups and >=75% usage |
| * of allocated virtual address space. |
| * |
| * RETURNS: |
| * On success, pointer to the new allocation_info is returned. On |
| * failure, ERR_PTR value is returned. |
| */ |
| static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info( |
| size_t reserved_size, size_t dyn_size, |
| size_t atom_size, |
| pcpu_fc_cpu_distance_fn_t cpu_distance_fn) |
| { |
| static int group_map[NR_CPUS] __initdata; |
| static int group_cnt[NR_CPUS] __initdata; |
| static struct cpumask mask __initdata; |
| const size_t static_size = __per_cpu_end - __per_cpu_start; |
| int nr_groups = 1, nr_units = 0; |
| size_t size_sum, min_unit_size, alloc_size; |
| int upa, max_upa, best_upa; /* units_per_alloc */ |
| int last_allocs, group, unit; |
| unsigned int cpu, tcpu; |
| struct pcpu_alloc_info *ai; |
| unsigned int *cpu_map; |
| |
| /* this function may be called multiple times */ |
| memset(group_map, 0, sizeof(group_map)); |
| memset(group_cnt, 0, sizeof(group_cnt)); |
| cpumask_clear(&mask); |
| |
| /* calculate size_sum and ensure dyn_size is enough for early alloc */ |
| size_sum = PFN_ALIGN(static_size + reserved_size + |
| max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE)); |
| dyn_size = size_sum - static_size - reserved_size; |
| |
| /* |
| * Determine min_unit_size, alloc_size and max_upa such that |
| * alloc_size is multiple of atom_size and is the smallest |
| * which can accommodate 4k aligned segments which are equal to |
| * or larger than min_unit_size. |
| */ |
| min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); |
| |
| /* determine the maximum # of units that can fit in an allocation */ |
| alloc_size = roundup(min_unit_size, atom_size); |
| upa = alloc_size / min_unit_size; |
| while (alloc_size % upa || (offset_in_page(alloc_size / upa))) |
| upa--; |
| max_upa = upa; |
| |
| cpumask_copy(&mask, cpu_possible_mask); |
| |
| /* group cpus according to their proximity */ |
| for (group = 0; !cpumask_empty(&mask); group++) { |
| /* pop the group's first cpu */ |
| cpu = cpumask_first(&mask); |
| group_map[cpu] = group; |
| group_cnt[group]++; |
| cpumask_clear_cpu(cpu, &mask); |
| |
| for_each_cpu(tcpu, &mask) { |
| if (!cpu_distance_fn || |
| (cpu_distance_fn(cpu, tcpu) == LOCAL_DISTANCE && |
| cpu_distance_fn(tcpu, cpu) == LOCAL_DISTANCE)) { |
| group_map[tcpu] = group; |
| group_cnt[group]++; |
| cpumask_clear_cpu(tcpu, &mask); |
| } |
| } |
| } |
| nr_groups = group; |
| |
| /* |
| * Wasted space is caused by a ratio imbalance of upa to group_cnt. |
| * Expand the unit_size until we use >= 75% of the units allocated. |
| * Related to atom_size, which could be much larger than the unit_size. |
| */ |
| last_allocs = INT_MAX; |
| best_upa = 0; |
| for (upa = max_upa; upa; upa--) { |
| int allocs = 0, wasted = 0; |
| |
| if (alloc_size % upa || (offset_in_page(alloc_size / upa))) |
| continue; |
| |
| for (group = 0; group < nr_groups; group++) { |
| int this_allocs = DIV_ROUND_UP(group_cnt[group], upa); |
| allocs += this_allocs; |
| wasted += this_allocs * upa - group_cnt[group]; |
| } |
| |
| /* |
| * Don't accept if wastage is over 1/3. The |
| * greater-than comparison ensures upa==1 always |
| * passes the following check. |
| */ |
| if (wasted > num_possible_cpus() / 3) |
| continue; |
| |
| /* and then don't consume more memory */ |
| if (allocs > last_allocs) |
| break; |
| last_allocs = allocs; |
| best_upa = upa; |
| } |
| BUG_ON(!best_upa); |
| upa = best_upa; |
| |
| /* allocate and fill alloc_info */ |
| for (group = 0; group < nr_groups; group++) |
| nr_units += roundup(group_cnt[group], upa); |
| |
| ai = pcpu_alloc_alloc_info(nr_groups, nr_units); |
| if (!ai) |
| return ERR_PTR(-ENOMEM); |
| cpu_map = ai->groups[0].cpu_map; |
| |
| for (group = 0; group < nr_groups; group++) { |
| ai->groups[group].cpu_map = cpu_map; |
| cpu_map += roundup(group_cnt[group], upa); |
| } |
| |
| ai->static_size = static_size; |
| ai->reserved_size = reserved_size; |
| ai->dyn_size = dyn_size; |
| ai->unit_size = alloc_size / upa; |
| ai->atom_size = atom_size; |
| ai->alloc_size = alloc_size; |
| |
| for (group = 0, unit = 0; group < nr_groups; group++) { |
| struct pcpu_group_info *gi = &ai->groups[group]; |
| |
| /* |
| * Initialize base_offset as if all groups are located |
| * back-to-back. The caller should update this to |
| * reflect actual allocation. |
| */ |
| gi->base_offset = unit * ai->unit_size; |
| |
| for_each_possible_cpu(cpu) |
| if (group_map[cpu] == group) |
| gi->cpu_map[gi->nr_units++] = cpu; |
| gi->nr_units = roundup(gi->nr_units, upa); |
| unit += gi->nr_units; |
| } |
| BUG_ON(unit != nr_units); |
| |
| return ai; |
| } |
| #endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */ |
| |
| #if defined(BUILD_EMBED_FIRST_CHUNK) |
| /** |
| * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem |
| * @reserved_size: the size of reserved percpu area in bytes |
| * @dyn_size: minimum free size for dynamic allocation in bytes |
| * @atom_size: allocation atom size |
| * @cpu_distance_fn: callback to determine distance between cpus, optional |
| * @alloc_fn: function to allocate percpu page |
| * @free_fn: function to free percpu page |
| * |
| * This is a helper to ease setting up embedded first percpu chunk and |
| * can be called where pcpu_setup_first_chunk() is expected. |
| * |
| * If this function is used to setup the first chunk, it is allocated |
| * by calling @alloc_fn and used as-is without being mapped into |
| * vmalloc area. Allocations are always whole multiples of @atom_size |
| * aligned to @atom_size. |
| * |
| * This enables the first chunk to piggy back on the linear physical |
| * mapping which often uses larger page size. Please note that this |
| * can result in very sparse cpu->unit mapping on NUMA machines thus |
| * requiring large vmalloc address space. Don't use this allocator if |
| * vmalloc space is not orders of magnitude larger than distances |
| * between node memory addresses (ie. 32bit NUMA machines). |
| * |
| * @dyn_size specifies the minimum dynamic area size. |
| * |
| * If the needed size is smaller than the minimum or specified unit |
| * size, the leftover is returned using @free_fn. |
| * |
| * RETURNS: |
| * 0 on success, -errno on failure. |
| */ |
| int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size, |
| size_t atom_size, |
| pcpu_fc_cpu_distance_fn_t cpu_distance_fn, |
| pcpu_fc_alloc_fn_t alloc_fn, |
| pcpu_fc_free_fn_t free_fn) |
| { |
| void *base = (void *)ULONG_MAX; |
| void **areas = NULL; |
| struct pcpu_alloc_info *ai; |
| size_t size_sum, areas_size; |
| unsigned long max_distance; |
| int group, i, highest_group, rc = 0; |
| |
| ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size, |
| cpu_distance_fn); |
| if (IS_ERR(ai)) |
| return PTR_ERR(ai); |
| |
| size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; |
| areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *)); |
| |
| areas = memblock_alloc(areas_size, SMP_CACHE_BYTES); |
| if (!areas) { |
| rc = -ENOMEM; |
| goto out_free; |
| } |
| |
| /* allocate, copy and determine base address & max_distance */ |
| highest_group = 0; |
| for (group = 0; group < ai->nr_groups; group++) { |
| struct pcpu_group_info *gi = &ai->groups[group]; |
| unsigned int cpu = NR_CPUS; |
| void *ptr; |
| |
| for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++) |
| cpu = gi->cpu_map[i]; |
| BUG_ON(cpu == NR_CPUS); |
| |
| /* allocate space for the whole group */ |
| ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size); |
| if (!ptr) { |
| rc = -ENOMEM; |
| goto out_free_areas; |
| } |
| /* kmemleak tracks the percpu allocations separately */ |
| kmemleak_free(ptr); |
| areas[group] = ptr; |
| |
| base = min(ptr, base); |
| if (ptr > areas[highest_group]) |
| highest_group = group; |
| } |
| max_distance = areas[highest_group] - base; |
| max_distance += ai->unit_size * ai->groups[highest_group].nr_units; |
| |
| /* warn if maximum distance is further than 75% of vmalloc space */ |
| if (max_distance > VMALLOC_TOTAL * 3 / 4) { |
| pr_warn("max_distance=0x%lx too large for vmalloc space 0x%lx\n", |
| max_distance, VMALLOC_TOTAL); |
| #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
| /* and fail if we have fallback */ |
| rc = -EINVAL; |
| goto out_free_areas; |
| #endif |
| } |
| |
| /* |
| * Copy data and free unused parts. This should happen after all |
| * allocations are complete; otherwise, we may end up with |
| * overlapping groups. |
| */ |
| for (group = 0; group < ai->nr_groups; group++) { |
| struct pcpu_group_info *gi = &ai->groups[group]; |
| void *ptr = areas[group]; |
| |
| for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) { |
| if (gi->cpu_map[i] == NR_CPUS) { |
| /* unused unit, free whole */ |
| free_fn(ptr, ai->unit_size); |
| continue; |
| } |
| /* copy and return the unused part */ |
| memcpy(ptr, __per_cpu_load, ai->static_size); |
| free_fn(ptr + size_sum, ai->unit_size - size_sum); |
| } |
| } |
| |
| /* base address is now known, determine group base offsets */ |
| for (group = 0; group < ai->nr_groups; group++) { |
| ai->groups[group].base_offset = areas[group] - base; |
| } |
| |
| pr_info("Embedded %zu pages/cpu s%zu r%zu d%zu u%zu\n", |
| PFN_DOWN(size_sum), ai->static_size, ai->reserved_size, |
| ai->dyn_size, ai->unit_size); |
| |
| pcpu_setup_first_chunk(ai, base); |
| goto out_free; |
| |
| out_free_areas: |
| for (group = 0; group < ai->nr_groups; group++) |
| if (areas[group]) |
| free_fn(areas[group], |
| ai->groups[group].nr_units * ai->unit_size); |
| out_free: |
| pcpu_free_alloc_info(ai); |
| if (areas) |
| memblock_free_early(__pa(areas), areas_size); |
| return rc; |
| } |
| #endif /* BUILD_EMBED_FIRST_CHUNK */ |
| |
| #ifdef BUILD_PAGE_FIRST_CHUNK |
| /** |
| * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages |
| * @reserved_size: the size of reserved percpu area in bytes |
| * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE |
| * @free_fn: function to free percpu page, always called with PAGE_SIZE |
| * @populate_pte_fn: function to populate pte |
| * |
| * This is a helper to ease setting up page-remapped first percpu |
| * chunk and can be called where pcpu_setup_first_chunk() is expected. |
| * |
| * This is the basic allocator. Static percpu area is allocated |
| * page-by-page into vmalloc area. |
| * |
| * RETURNS: |
| * 0 on success, -errno on failure. |
| */ |
| int __init pcpu_page_first_chunk(size_t reserved_size, |
| pcpu_fc_alloc_fn_t alloc_fn, |
| pcpu_fc_free_fn_t free_fn, |
| pcpu_fc_populate_pte_fn_t populate_pte_fn) |
| { |
| static struct vm_struct vm; |
| struct pcpu_alloc_info *ai; |
| char psize_str[16]; |
| int unit_pages; |
| size_t pages_size; |
| struct page **pages; |
| int unit, i, j, rc = 0; |
| int upa; |
| int nr_g0_units; |
| |
| snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10); |
| |
| ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL); |
| if (IS_ERR(ai)) |
| return PTR_ERR(ai); |
| BUG_ON(ai->nr_groups != 1); |
| upa = ai->alloc_size/ai->unit_size; |
| nr_g0_units = roundup(num_possible_cpus(), upa); |
| if (WARN_ON(ai->groups[0].nr_units != nr_g0_units)) { |
| pcpu_free_alloc_info(ai); |
| return -EINVAL; |
| } |
| |
| unit_pages = ai->unit_size >> PAGE_SHIFT; |
| |
| /* unaligned allocations can't be freed, round up to page size */ |
| pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() * |
| sizeof(pages[0])); |
| pages = memblock_alloc(pages_size, SMP_CACHE_BYTES); |
| if (!pages) |
| panic("%s: Failed to allocate %zu bytes\n", __func__, |
| pages_size); |
| |
| /* allocate pages */ |
| j = 0; |
| for (unit = 0; unit < num_possible_cpus(); unit++) { |
| unsigned int cpu = ai->groups[0].cpu_map[unit]; |
| for (i = 0; i < unit_pages; i++) { |
| void *ptr; |
| |
| ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE); |
| if (!ptr) { |
| pr_warn("failed to allocate %s page for cpu%u\n", |
| psize_str, cpu); |
| goto enomem; |
| } |
| /* kmemleak tracks the percpu allocations separately */ |
| kmemleak_free(ptr); |
| pages[j++] = virt_to_page(ptr); |
| } |
| } |
| |
| /* allocate vm area, map the pages and copy static data */ |
| vm.flags = VM_ALLOC; |
| vm.size = num_possible_cpus() * ai->unit_size; |
| vm_area_register_early(&vm, PAGE_SIZE); |
| |
| for (unit = 0; unit < num_possible_cpus(); unit++) { |
| unsigned long unit_addr = |
| (unsigned long)vm.addr + unit * ai->unit_size; |
| |
| for (i = 0; i < unit_pages; i++) |
| populate_pte_fn(unit_addr + (i << PAGE_SHIFT)); |
| |
| /* pte already populated, the following shouldn't fail */ |
| rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages], |
| unit_pages); |
| if (rc < 0) |
| panic("failed to map percpu area, err=%d\n", rc); |
| |
| /* |
| * FIXME: Archs with virtual cache should flush local |
| * cache for the linear mapping here - something |
| * equivalent to flush_cache_vmap() on the local cpu. |
| * flush_cache_vmap() can't be used as most supporting |
| * data structures are not set up yet. |
| */ |
| |
| /* copy static data */ |
| memcpy((void *)unit_addr, __per_cpu_load, ai->static_size); |
| } |
| |
| /* we're ready, commit */ |
| pr_info("%d %s pages/cpu s%zu r%zu d%zu\n", |
| unit_pages, psize_str, ai->static_size, |
| ai->reserved_size, ai->dyn_size); |
| |
| pcpu_setup_first_chunk(ai, vm.addr); |
| goto out_free_ar; |
| |
| enomem: |
| while (--j >= 0) |
| free_fn(page_address(pages[j]), PAGE_SIZE); |
| rc = -ENOMEM; |
| out_free_ar: |