From: Usama Arif <usama.arif@linux.dev>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
david@kernel.org, linux-mm@kvack.org, hannes@cmpxchg.org,
tj@kernel.org, shakeel.butt@linux.dev, roman.gushchin@linux.dev,
liam@infradead.org, linux-kernel@vger.kernel.org, ljs@kernel.org,
mhocko@suse.com, rppt@kernel.org, surenb@google.com,
vbabka@kernel.org, kernel-team@meta.com
Subject: Re: [PATCH v2 2/2] mm/vmpressure: split v1 userspace eventfd code into vmpressure-v1.c
Date: Mon, 29 Jun 2026 14:55:57 +0100 [thread overview]
Message-ID: <fb000c9a-add2-4c31-afe1-b6ec416c9058@linux.dev> (raw)
In-Reply-To: <akJzXU52XJ9-F2IB@localhost.localdomain>
On 29/06/2026 14:34, Michal Koutný wrote:
> On Mon, Jun 29, 2026 at 05:59:37AM -0700, Usama Arif <usama.arif@linux.dev> wrote:
>> This split is the first step toward eventually making vmpressure
>> CONFIG_MEMCG_V1 only. The v2 in-kernel socket pressure path
>> (tree=false) cannot be removed today immediately: PSI is not an
>> exact replacement for vmpressure, and switching networking socket-buffer
>> back-off to PSI
>
> (Here I understand PSI is a different and differntly scope metric) but
> what does it mean when you write that tree=false cannot be removed but
> the other patch bails out from vmpressure() (i.e. nothing is updated
> anyway)?
So the first patch bails out for cgroup v2 for tree = true only.
For tree = false, it doesn't bail out, and is still used for networking
socket-buffer back-off. I think that is a whole another scope of work
switching to PSI. Hope that makes sense?
Thanks,
Usama
next prev parent reply other threads:[~2026-06-29 13:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-29 12:59 [PATCH v2 0/2] mm/vmpressure: reduce CPU, memory and code overhead on cgroup v2 Usama Arif
2026-06-29 12:59 ` [PATCH v2 1/2] mm/vmpressure: skip tree=true accounting " Usama Arif
2026-06-29 16:46 ` Johannes Weiner
2026-06-29 12:59 ` [PATCH v2 2/2] mm/vmpressure: split v1 userspace eventfd code into vmpressure-v1.c Usama Arif
2026-06-29 13:34 ` Michal Koutný
2026-06-29 13:55 ` Usama Arif [this message]
2026-06-29 14:29 ` Michal Koutný
2026-06-29 15:20 ` Usama Arif
2026-06-29 17:13 ` Michal Koutný
2026-06-29 15:57 ` Shakeel Butt
2026-06-29 16:48 ` Johannes Weiner
2026-06-29 17:23 ` Usama Arif
2026-06-29 18:12 ` Johannes Weiner
2026-06-29 18:28 ` Shakeel Butt
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