android-mainline/SUBMIT-ANDROID-Make-vsock-virtio-packet-buff-size-configurable.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Ram Muthiah <rammuthiah@google.com>
Date: Tue, 26 Jan 2021 20:27:32 -0800
Subject: SUBMIT: ANDROID: Make vsock virtio packet buff size configurable

When the android virtual device stays up for long periods of time, the
SLAB sustains everincreasing fragmentation. Contributing to this
fragmentation are the virtio packet buffer allocations which are a
drain on 64Kb compound pages. Eventually these can't be allocated due to
fragmentation.

To enable successful allocations for this packet buffer, the packet
buffer's size needs to be reduced.

To enable a reduction without impacting other partners, this var is
being exposed as a command line param.

[CPNOTE: 06/07/21] Lee: Pinged the bug for status
[CPNOTE: 15/07/21] Lee: Ram suggests that this should go upstream

Bug: 149494272
Test: atest ManagedProfileLifecycleStressTest#testCreateStartDelete on
local cuttlefish device
Signed-off-by: Ram Muthiah <rammuthiah@google.com>
Change-Id: Ia4f9180025b64d61d9e2b882daa84460b8f08fd2
---
 include/linux/virtio_vsock.h            | 3 ++-
 net/vmw_vsock/virtio_transport_common.c | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -9,7 +9,8 @@
 
 #define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 4)
 #define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
-#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
+#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		virtio_transport_max_vsock_pkt_buf_size
+extern uint virtio_transport_max_vsock_pkt_buf_size;
 
 enum {
 	VSOCK_VQ_RX     = 0, /* for host to guest data */
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -26,6 +26,10 @@
 /* Threshold for detecting small packets to copy */
 #define GOOD_COPY_LEN  128
 
+uint virtio_transport_max_vsock_pkt_buf_size = 64 * 1024;
+module_param(virtio_transport_max_vsock_pkt_buf_size, uint, 0444);
+EXPORT_SYMBOL_GPL(virtio_transport_max_vsock_pkt_buf_size);
+
 static const struct virtio_transport *
 virtio_transport_get_ops(struct vsock_sock *vsk)
 {