On Wed, Oct 15, 2025 at 03:57:29PM +0200, Daniel Sedlak wrote:

On 10/14/25 10:32 PM, Shakeel Butt wrote:

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On Mon, Oct 13, 2025 at 04:30:53PM +0200, Daniel Sedlak wrote:
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How about we track the actions taken by the callers of
mem_cgroup_sk_under_memory_pressure()? Basically if network stack
reduces the buffer size or whatever the other actions it may take when
mem_cgroup_sk_under_memory_pressure() returns, tracking those actions
is what I think is needed here, at least for the debugging use-case.

I am not against it, but I feel that conveying those tracked actions (or how
to represent them) to the user will be much harder. Are there already
existing APIs to push this information to the user?

I discussed with Wei Wang and she suggested we should start tracking the
calls to tcp_adjust_rcv_ssthresh() first. So, something like the
following. I would like feedback frm networking folks as well:

Looks like a good start. Are you planning on sending this patch separately,
or can we include it in our v6 (with maybe slight modifications)?

What else you are planning to add in v6?

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diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 873e510d6f8d..5fe254813123 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h

@@ -52,6 +52,7 @@ enum memcg_memory_event {
  	MEMCG_SWAP_HIGH,
  	MEMCG_SWAP_MAX,
  	MEMCG_SWAP_FAIL,
+	MEMCG_SOCK_THROTTLED,

This probably should be MEMCG_TCP_SOCK_THROTTLED, because it checks only
tcp_under_memory_pressure, however there is also the
sk_under_memory_pressure used in net/sctp/sm_statefuns.c:6597 to also reduce
the sending rate. Or also add the counter there and keep the name?

Yeah makes sense to add the counter in sctp as well.