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

[Muchun Song <songmuchun@bytedance.com>]

On Sun, Oct 11, 2020 at 12:37 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>
> 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.

Will do. Thanks for your suggestions.

>
> --
> ~Randy
>


-- 
Yours,
Muchun