From: Gregory Price <gourry@gourry.net>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frank van der Linden <fvdl@google.com>,
Yiannis Nikolakopoulos <yiannis.nikolakop@gmail.com>,
Thomas Gleixner <tglx@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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Andrew Morton <akpm@linux-foundation.org>,
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"Liam R. Howlett" <Liam.Howlett@oracle.com>,
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Alirad Malek <alirad.malek@zptcorp.com>
Subject: Re: [PATCH RFC v2 0/3] Demote to lower tier using non-temporal stores
Date: Thu, 30 Jul 2026 16:49:24 -0400 [thread overview]
Message-ID: <amu4cfko8YY9awfF@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <amuTOC7qxWHVyZcO@cmpxchg.org>
On Thu, Jul 30, 2026 at 02:08:56PM -0400, Johannes Weiner wrote:
> On Thu, Jul 30, 2026 at 10:40:32AM -0700, Frank van der Linden wrote:
> > On Thu, Jul 30, 2026 at 10:30 AM Gregory Price <gourry@gourry.net> wrote:
>
> > arm64 already seems to use stores with NT hints by default.
> >
> > In general, though, I agree that for ASYNC requests, just always using
> > NT seems fine.
> >
> > Maybe the mode and reason should be folded in to one variable, so
> > that, further down the stack, a decision can be made as to what type
> > of copy to use? E.g. if the mode is !MIGRATE_ASYNC and the reason is
> > MR_DEMOTION, then non-temporal is still a good choice. If the mode is
> > MIGRATE_ASYNC, NT is still a good idea. If you wanted to get fancy,
> > any mode with folio_test_waiters(folio) == true should not use NT,
> > since a task is waiting to use the data, so caching it is better.
> > Maybe that's overthinking it.
>
> Agree. `reason' seems like a much stronger signal.
I think this ends up cleaner as well, it would be a nice improvement.
~Gregory
prev parent reply other threads:[~2026-07-30 20:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-30 15:02 [PATCH RFC v2 0/3] Demote to lower tier using non-temporal stores Yiannis Nikolakopoulos
2026-07-30 15:02 ` [PATCH RFC v2 1/3] mm, x86: support copying a folio " Yiannis Nikolakopoulos
2026-07-30 15:02 ` [PATCH RFC v2 2/3] mm: new migrate_mode flag for async " Yiannis Nikolakopoulos
2026-07-30 15:02 ` [PATCH RFC v2 3/3] mm: use non-temporal stores for demotion Yiannis Nikolakopoulos
2026-07-30 17:30 ` [PATCH RFC v2 0/3] Demote to lower tier using non-temporal stores Gregory Price
2026-07-30 17:40 ` Frank van der Linden
2026-07-30 18:08 ` Johannes Weiner
2026-07-30 20:49 ` Gregory Price [this message]
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