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

[Mike Rapoport]

On Tue, Oct 13, 2020 at 07:43:59AM -0700, Randy Dunlap wrote:
> On 10/13/20 1:09 AM, Mike Rapoport wrote:
> > On Mon, Oct 12, 2020 at 05:53:01PM +0800, Muchun Song wrote:
> >> On Mon, Oct 12, 2020 at 5:24 PM Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> >>>
> >>> On 10/12/20 10:39 AM, Muchun Song wrote:
> >>>> On Mon, Oct 12, 2020 at 3:42 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
> >>
> >> We are not complaining about TCP using too much memory, but how do
> >> we know that TCP uses a lot of memory. When I firstly face this problem,
> >> I do not know who uses the 25GB memory and it is not shown in the /proc/meminfo.
> >> If we can know the amount memory of the socket buffer via /proc/meminfo, we
> >> may not need to spend a lot of time troubleshooting this problem. Not everyone
> >> knows that a lot of memory may be used here. But I believe many people
> >> should know /proc/meminfo to confirm memory users.
> > 
> > If I undestand correctly, the problem you are trying to solve is to
> > simplify troubleshooting of memory usage for people who may not be aware
> > that networking stack can be a large memory consumer.
> > 
> > For that a paragraph in 'man 5 proc' maybe a good start:
> > 
> >>From ddbcf38576d1a2b0e36fe25a27350d566759b664 Mon Sep 17 00:00:00 2001
> > From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> > Date: Tue, 13 Oct 2020 11:07:35 +0300
> > Subject: [PATCH] proc.5: meminfo: add not anout network stack memory
> >  consumption
> > 
> > Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> > ---
> >  man5/proc.5 | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/man5/proc.5 b/man5/proc.5
> > index ed309380b..8414676f1 100644
> > --- a/man5/proc.5
> > +++ b/man5/proc.5
> > @@ -3478,6 +3478,14 @@ Except as noted below,
> >  all of the fields have been present since at least Linux 2.6.0.
> >  Some fields are displayed only if the kernel was configured
> >  with various options; those dependencies are noted in the list.
> > +.IP
> > +Note that significant part of memory allocated by the network stack
> > +is not accounted in the file.
> > +The memory consumption of the network stack can be queried
> > +using
> > +.IR /proc/net/sockstat
> > +or
> > +.BR ss (8)
> >  .RS
> >  .TP
> >  .IR MemTotal " %lu"
> 
> Hi Mike,
> 
> Could you tell us what units those values are in?
> or is that already explained somewhere else?

It is described a few lines above and anyway, "MemTotal" is a part of
the diff context ;-)

> thanks.
> -- 
> ~Randy
> 
> 

-- 
Sincerely yours,
Mike.