Thread (25 messages) 25 messages, 9 authors, 2020-10-19

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

From: Randy Dunlap <hidden>
Date: 2020-10-13 15:21:43
Also in: linux-fsdevel, linux-mm, lkml, virtualization

On 10/13/20 8:12 AM, Mike Rapoport wrote:
On Tue, Oct 13, 2020 at 07:43:59AM -0700, Randy Dunlap wrote:
quoted
On 10/13/20 1:09 AM, Mike Rapoport wrote:
quoted
On Mon, Oct 12, 2020 at 05:53:01PM +0800, Muchun Song wrote:
quoted
On Mon, Oct 12, 2020 at 5:24 PM Eric Dumazet [off-list ref] wrote:
quoted
On 10/12/20 10:39 AM, Muchun Song wrote:
quoted
On Mon, Oct 12, 2020 at 3:42 PM Eric Dumazet [off-list ref] 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:
quoted
From ddbcf38576d1a2b0e36fe25a27350d566759b664 Mon Sep 17 00:00:00 2001
From: Mike Rapoport <redacted>
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 <redacted>
---
 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 ;-)
with no units AFAICT.

But I was unclear. I wasn't referring to /proc/meminfo, but instead
to /proc/net/sockstat and its units:

sockets: used 1224
TCP: inuse 11 orphan 1 tw 1 alloc 26 mem 3
UDP: inuse 4 mem 2
UDPLITE: inuse 0
RAW: inuse 0
FRAG: inuse 0 memory 0

E.g., for TCP and UDP, are those socket counts or some unit of memory?
If units of memory, what unit size?

thanks.
-- 
~Randy
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