From: Matthew Wilcox <willy@infradead.org>
To: Gregory Price <gourry@gourry.net>
Cc: Bharata B Rao <bharata@amd.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
AneeshKumar.KizhakeVeetil@arm.com, Hasan.Maruf@amd.com,
Jonathan.Cameron@huawei.com, Michael.Day@amd.com,
akpm@linux-foundation.org, dave.hansen@intel.com,
david@redhat.com, feng.tang@intel.com, hannes@cmpxchg.org,
honggyu.kim@sk.com, hughd@google.com, jhubbard@nvidia.com,
k.shutemov@gmail.com, kbusch@meta.com, kmanaouil.dev@gmail.com,
leesuyeon0506@gmail.com, leillc@google.com,
liam.howlett@oracle.com, mgorman@techsingularity.net,
mingo@redhat.com, nadav.amit@gmail.com, nphamcs@gmail.com,
peterz@infradead.org, raghavendra.kt@amd.com, riel@surriel.com,
rientjes@google.com, rppt@kernel.org, shivankg@amd.com,
shy828301@gmail.com, sj@kernel.org, vbabka@suse.cz,
weixugc@google.com, ying.huang@linux.alibaba.com, ziy@nvidia.com,
dave@stgolabs.net, yuanchu@google.com, hyeonggon.yoo@sk.com
Subject: Re: [RFC PATCH 1/4] mm: migrate: Allow misplaced migration without VMA too
Date: Thu, 6 Mar 2025 18:42:10 +0000 [thread overview]
Message-ID: <Z8nsgr46eVH7W7SJ@casper.infradead.org> (raw)
In-Reply-To: <Z8nnPYldSXs5TYND@gourry-fedora-PF4VCD3F>
On Thu, Mar 06, 2025 at 01:19:41PM -0500, Gregory Price wrote:
> On Thu, Mar 06, 2025 at 05:45:34PM +0000, Matthew Wilcox wrote:
> > On Thu, Mar 06, 2025 at 12:24:16PM -0500, Gregory Price wrote:
> > > we may also need this:
> > > https://lore.kernel.org/linux-mm/20250107000346.1338481-4-gourry@gourry.net/
> > >
> > > May be worth just pulling these ahead to avoid conflict.
> >
> > Or not putting them in at all because this whole thing is a magnificent
> > waste of time?
>
> Divorced from the tiering mechanisms, is making misplaced migration able
> to migrate unmapped pages not generally useful?
The only thing I can think of is if you have a process or set of
processes on node A calling read() and the file is cached on node B.
But in order to decide if the page is on the wrong node, you'd need
to track a lot of information about which nodes the page is being
accessed from. Which is probably why we've never bothered to do it.
This is not a large patch for you to carry as part of your patchset.
There's nothing intrinsically wrong with it; it just has no users in
mainline and no real prospect of any being added soon.
next prev parent reply other threads:[~2025-03-06 18:42 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-06 5:45 [RFC PATCH 0/4] Kernel daemon for detecting and promoting hot pages Bharata B Rao
2025-03-06 5:45 ` [RFC PATCH 1/4] mm: migrate: Allow misplaced migration without VMA too Bharata B Rao
2025-03-06 12:13 ` David Hildenbrand
2025-03-07 3:00 ` Bharata B Rao
2025-03-06 17:24 ` Gregory Price
2025-03-06 17:45 ` Matthew Wilcox
2025-03-06 18:19 ` Gregory Price
2025-03-06 18:42 ` Matthew Wilcox [this message]
2025-03-06 20:03 ` Gregory Price
2025-03-24 2:55 ` Balbir Singh
2025-03-24 14:51 ` Bharata B Rao
2025-03-06 5:45 ` [RFC PATCH 2/4] mm: kpromoted: Hot page info collection and promotion daemon Bharata B Rao
2025-03-06 17:22 ` Mike Day
2025-03-07 3:27 ` Bharata B Rao
2025-03-13 16:44 ` Davidlohr Bueso
2025-03-17 3:39 ` Bharata B Rao
2025-03-17 15:05 ` Gregory Price
2025-03-17 16:22 ` Bharata B Rao
2025-03-17 18:24 ` Gregory Price
2025-03-13 20:36 ` Davidlohr Bueso
2025-03-17 3:49 ` Bharata B Rao
2025-03-14 15:28 ` Jonathan Cameron
2025-03-18 4:09 ` Bharata B Rao
2025-03-18 14:17 ` Jonathan Cameron
2025-03-24 3:35 ` Balbir Singh
2025-03-28 4:55 ` Bharata B Rao
2025-03-24 13:43 ` Gregory Price
2025-03-24 14:34 ` Bharata B Rao
2025-03-06 5:45 ` [RFC PATCH 3/4] x86: ibs: In-kernel IBS driver for memory access profiling Bharata B Rao
2025-03-14 15:38 ` Jonathan Cameron
2025-03-06 5:45 ` [RFC PATCH 4/4] x86: ibs: Enable IBS profiling for memory accesses Bharata B Rao
2025-03-16 22:00 ` [RFC PATCH 0/4] Kernel daemon for detecting and promoting hot pages SeongJae Park
2025-03-18 6:33 ` Raghavendra K T
2025-03-18 10:45 ` Bharata B Rao
2025-03-18 5:28 ` Balbir Singh
2025-03-20 9:07 ` Bharata B Rao
2025-03-21 6:19 ` Balbir Singh
2025-03-25 8:18 ` Bharata B Rao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Z8nsgr46eVH7W7SJ@casper.infradead.org \
--to=willy@infradead.org \
--cc=AneeshKumar.KizhakeVeetil@arm.com \
--cc=Hasan.Maruf@amd.com \
--cc=Jonathan.Cameron@huawei.com \
--cc=Michael.Day@amd.com \
--cc=akpm@linux-foundation.org \
--cc=bharata@amd.com \
--cc=dave.hansen@intel.com \
--cc=dave@stgolabs.net \
--cc=david@redhat.com \
--cc=feng.tang@intel.com \
--cc=gourry@gourry.net \
--cc=hannes@cmpxchg.org \
--cc=honggyu.kim@sk.com \
--cc=hughd@google.com \
--cc=hyeonggon.yoo@sk.com \
--cc=jhubbard@nvidia.com \
--cc=k.shutemov@gmail.com \
--cc=kbusch@meta.com \
--cc=kmanaouil.dev@gmail.com \
--cc=leesuyeon0506@gmail.com \
--cc=leillc@google.com \
--cc=liam.howlett@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mingo@redhat.com \
--cc=nadav.amit@gmail.com \
--cc=nphamcs@gmail.com \
--cc=peterz@infradead.org \
--cc=raghavendra.kt@amd.com \
--cc=riel@surriel.com \
--cc=rientjes@google.com \
--cc=rppt@kernel.org \
--cc=shivankg@amd.com \
--cc=shy828301@gmail.com \
--cc=sj@kernel.org \
--cc=vbabka@suse.cz \
--cc=weixugc@google.com \
--cc=ying.huang@linux.alibaba.com \
--cc=yuanchu@google.com \
--cc=ziy@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox