From: Michal Hocko <mhocko@suse.com>
To: Benjamin Lee McQueen <mcq@disroot.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v3] mm/vmpressure: scale window size based on machine memory
Date: Fri, 6 Mar 2026 16:52:47 +0100 [thread overview]
Message-ID: <aar4T90zjolmTGFa@tiehlicka> (raw)
In-Reply-To: <20260305043038.2176-1-mcq@disroot.org>
On Wed 04-03-26 22:30:38, Benjamin Lee McQueen wrote:
> the vmpressure window size has been fixed at 512 pages
> (SWAP_CLUSTER_MAX * 16), ever since the file's inception. a TODO in
> the file notes that the vmpressure window size should be scaled
> similarly to vmstat's scaling, via machine size.
>
> the problem with fixed window size on large memory systems:
Thank you for this much more detail insight into your thinking. This is
a good start. I am still missing an overall motivation though. Are you
trying to address a theoretical concern (the said TODO) or do you have
any practical workload that generates bogus vmpressure events. Also
please note that vmpressure is a legacy notification interface only
available in cgroup v1. PSI (via memory.pressure or global
/proc/pressure/) is a new/preferred method to measure memory pressure.
See more Documentation/accounting/psi.rst
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2026-03-06 15:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-27 22:15 [PATCH] mm/vmpressure: scale window size based on machine memory and CPU count Benjamin Lee McQueen
2026-03-02 8:56 ` Michal Hocko
2026-03-02 12:15 ` Lorenzo Stoakes
2026-03-05 4:30 ` [RFC PATCH v3] mm/vmpressure: scale window size based on machine memory Benjamin Lee McQueen
2026-03-06 15:52 ` Michal Hocko [this message]
2026-03-06 16:44 ` Benjamin Lee McQueen
2026-03-12 7:18 ` Michal Hocko
2026-03-12 9:50 ` David Hildenbrand (Arm)
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