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

From: Mike Rapoport <[email-masked]>
Date: Sun, 11 Oct 2020 16:52:44 +0300

On Sat, Oct 10, 2020 at 06:38:54PM +0800, 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.
 
I have a high lelel question.
There is accounting of the socket memory for memcg that gets called from
the networking layer. Did you check if the same call sites can be used
for the system-wide accounting as well?

>   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 <[email-masked]>
> ---
>  drivers/base/node.c      |  2 ++
>  drivers/net/virtio_net.c |  3 +--

Is virtio-net the only dirver that requred an update?

>  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(-)
>