Re: [PATCH] mm: proc: add Sock to /proc/meminfo

Randy Dunlap
2020-10-10T22:51:48Z

Hi,

On 10/10/20 3:38 AM, Muchun Song wrote:
> The amount of memory allocated to sockets buffer can become significant.
> However, we do not display the amount of memory consumed by sockets
> buffer. In this case, knowing where the memory is consumed by the kernel
> is very difficult. On our server with 500GB RAM, sometimes we can see
> 25GB disappear through /proc/meminfo. After our analysis, we found the
> following memory allocation path which consumes the memory with page_owner
> enabled.
>
> 849698 times:
> Page allocated via order 3, mask 0x4052c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP)
> __alloc_pages_nodemask+0x11d/0x290
> skb_page_frag_refill+0x68/0xf0
> sk_page_frag_refill+0x19/0x70
> tcp_sendmsg_locked+0x2f4/0xd10
> tcp_sendmsg+0x29/0xa0
> sock_sendmsg+0x30/0x40
> sock_write_iter+0x8f/0x100
> __vfs_write+0x10b/0x190
> vfs_write+0xb0/0x190
> ksys_write+0x5a/0xd0
> do_syscall_64+0x5d/0x110
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> ---
> drivers/base/node.c | 2 ++
> drivers/net/virtio_net.c | 3 +--
> fs/proc/meminfo.c | 1 +
> include/linux/mmzone.h | 1 +
> include/linux/skbuff.h | 43 ++++++++++++++++++++++++++++++++++++++--
> kernel/exit.c | 3 +--
> mm/page_alloc.c | 7 +++++--
> mm/vmstat.c | 1 +
> net/core/sock.c | 8 ++++----
> net/ipv4/tcp.c | 3 +--
> net/xfrm/xfrm_state.c | 3 +--
> 11 files changed, 59 insertions(+), 16 deletions(-)

Thanks for finding that.

Please update Documentation/filesystems/proc.rst "meminfo" section also.

--
~Randy