| /* |
| |
| nsjail - CPU affinity |
| ----------------------------------------- |
| |
| Copyright 2017 Google Inc. All Rights Reserved. |
| |
| Licensed under the Apache License, Version 2.0 (the "License"); |
| you may not use this file except in compliance with the License. |
| You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| |
| */ |
| |
| #include "cpu.h" |
| |
| #include <inttypes.h> |
| #include <sched.h> |
| #include <stdint.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include <memory> |
| |
| #include "logs.h" |
| #include "util.h" |
| |
| namespace cpu { |
| |
| static const std::string listCpusInSet(cpu_set_t* mask) { |
| std::string ret; |
| for (size_t i = 0; i < CPU_SETSIZE; i++) { |
| if (CPU_ISSET(i, mask)) { |
| if (!ret.empty()) { |
| ret.append(","); |
| } |
| ret.append(std::to_string(i)); |
| } |
| } |
| return ret; |
| } |
| |
| static size_t getNthOnlineCpu(cpu_set_t* mask, size_t n) { |
| for (size_t i = 0, j = 0; i < CPU_SETSIZE; i++) { |
| if (CPU_ISSET(i, mask)) { |
| if (j == n) { |
| return i; |
| } |
| j++; |
| } |
| } |
| LOG_F("No CPU #%zu found, yet there should be %zu left in the mask [%s]", n, |
| (size_t)CPU_COUNT(mask), listCpusInSet(mask).c_str()); |
| return 0; |
| } |
| |
| static void setRandomCpu(cpu_set_t* orig_mask, cpu_set_t* new_mask, size_t available_cpus) { |
| if (available_cpus == 0) { |
| LOG_F("There are no more CPUs left to use, and there should be at least 1 left"); |
| } |
| |
| size_t n = util::rnd64() % available_cpus; |
| n = getNthOnlineCpu(orig_mask, n); |
| |
| CPU_SET(n, new_mask); |
| LOG_D("Add CPU #%zu from the original mask=[%s] (size=%zu, available_cpus=%zu), new " |
| "mask=[%s] (size=%zu)", |
| n, listCpusInSet(orig_mask).c_str(), (size_t)CPU_COUNT(orig_mask), available_cpus, |
| listCpusInSet(new_mask).c_str(), (size_t)CPU_COUNT(new_mask)); |
| CPU_CLR(n, orig_mask); |
| } |
| |
| bool initCpu(nsjconf_t* nsjconf) { |
| if (nsjconf->max_cpus == 0) { |
| LOG_D("No max_cpus limit set"); |
| return true; |
| } |
| |
| std::unique_ptr<cpu_set_t> orig_mask(new cpu_set_t); |
| if (!orig_mask) { |
| PLOG_W("Failure allocating cpu_set_t"); |
| return false; |
| } |
| if (sched_getaffinity(0, CPU_ALLOC_SIZE(CPU_SETSIZE), orig_mask.get()) == -1) { |
| PLOG_W("sched_getaffinity(0, mask_size=%zu)", (size_t)CPU_ALLOC_SIZE(CPU_SETSIZE)); |
| return false; |
| } |
| size_t available_cpus = CPU_COUNT(orig_mask.get()); |
| |
| LOG_D("Original CPU set: [%s], with %zu allowed CPUs", |
| listCpusInSet(orig_mask.get()).c_str(), available_cpus); |
| |
| if (nsjconf->max_cpus > available_cpus) { |
| LOG_W( |
| "Number of requested CPUs is bigger than number of available CPUs (%zu > %zu)", |
| nsjconf->max_cpus, available_cpus); |
| return true; |
| } |
| if (nsjconf->max_cpus == available_cpus) { |
| LOG_D("All CPUs requested (%zu of %zu)", nsjconf->max_cpus, available_cpus); |
| return true; |
| } |
| |
| std::unique_ptr<cpu_set_t> new_mask(new cpu_set_t); |
| if (!new_mask) { |
| PLOG_W("Failure allocating cpu_set_t"); |
| return false; |
| } |
| CPU_ZERO(new_mask.get()); |
| |
| for (size_t i = 0; i < nsjconf->max_cpus; i++) { |
| setRandomCpu(orig_mask.get(), new_mask.get(), available_cpus); |
| available_cpus--; |
| } |
| |
| LOG_D("Setting new CPU mask=[%s] with %zu allowed CPUs (max_cpus=%zu), %zu CPUs " |
| "(CPU_COUNT=%zu) left mask=[%s]", |
| listCpusInSet(new_mask.get()).c_str(), nsjconf->max_cpus, |
| (size_t)CPU_COUNT(new_mask.get()), available_cpus, (size_t)CPU_COUNT(orig_mask.get()), |
| listCpusInSet(orig_mask.get()).c_str()); |
| |
| if (sched_setaffinity(0, CPU_ALLOC_SIZE(CPU_SETSIZE), new_mask.get()) == -1) { |
| PLOG_W("sched_setaffinity(mask=%s size=%zu max_cpus=%zu (CPU_COUNT=%zu)) failed", |
| listCpusInSet(new_mask.get()).c_str(), (size_t)CPU_ALLOC_SIZE(CPU_SETSIZE), |
| nsjconf->max_cpus, (size_t)CPU_COUNT(new_mask.get())); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| } // namespace cpu |