From: Andrew Morton <akpm@linux-foundation.org>
To: "JP Kobryn (Meta)" <jp.kobryn@linux.dev>
Cc: linux-mm@kvack.org, willy@infradead.org, hannes@cmpxchg.org,
david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com,
vbabka@kernel.org, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, kasong@tencent.com, qi.zheng@linux.dev,
shakeel.butt@linux.dev, baohua@kernel.org,
axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com,
riel@surriel.com, kuba@kernel.org, edumazet@google.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com
Subject: Re: [PATCH v3] mm/vmpressure: skip socket pressure for costly order reclaim
Date: Mon, 6 Apr 2026 12:16:01 -0700 [thread overview]
Message-ID: <20260406121601.0f4f3a6886098371e40d6711@linux-foundation.org> (raw)
In-Reply-To: <6a41259c-bf69-49d5-9cba-80a5feb8ee8a@linux.dev>
On Mon, 6 Apr 2026 12:07:57 -0700 "JP Kobryn (Meta)" <jp.kobryn@linux.dev> wrote:
> Let me know if this data helps, and if you'd like this added to the
> changelog.
>
> On one affected host with impacted net throughput, the memory state at
> the time showed ~15GB available, zero cgroup pressure, and the following
> buddyinfo state:
>
> Order FreePages
> 0: 133,970
> 1: 29,230
> 2: 17,351
> 3: 18,984
> 7+: 0
>
> Using bpf, it was found that 94% of vmpressure calls on this host were
> from order-7 kswapd reclaim.
>
> TCP minimum recv window is rcv_ssthresh:19712.
>
> Before patch:
> 723 out of 3,843 (19%) TCP connections stuck at minimum recv window
>
> After live-patching and ~30min elapsed:
> 0 out of 3,470 TCP connections stuck at minimum recv window
Well I'm impressed ;)
Yes please, it's a useful thing to include. When people look at a
contribution, question #1 is "why should I spend time on this". A
clear (and tasty) description of userspace benefit is the ideal way of
answering that.
prev parent reply other threads:[~2026-04-06 19:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-06 17:44 [PATCH v3] mm/vmpressure: skip socket pressure for costly order reclaim JP Kobryn (Meta)
2026-04-06 17:54 ` Andrew Morton
2026-04-06 19:07 ` JP Kobryn (Meta)
2026-04-06 19:16 ` Andrew Morton [this message]
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