From: Bing Jiao <bingjiao@google.com>
To: Donet Tom <donettom@linux.ibm.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
David Hildenbrand <david@kernel.org>,
Michal Hocko <mhocko@kernel.org>,
Qi Zheng <zhengqi.arch@bytedance.com>,
Shakeel Butt <shakeel.butt@linux.dev>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/2] mm/vmscan: balance demotion allocation in alloc_demote_folio()
Date: Fri, 9 Jan 2026 23:45:57 +0000 [thread overview]
Message-ID: <aWGTNfrLBhCM3_-9@google.com> (raw)
In-Reply-To: <761533a9-b188-43b1-a24a-1893622ce18c@linux.ibm.com>
On Thu, Jan 08, 2026 at 06:14:02PM +0530, Donet Tom wrote:
>
> On 1/7/26 12:58 PM, Bing Jiao wrote:
> > + /* Randomly select a node from fallback nodes for balanced allocation */
> > + if (allowed_mask) {
> > + mtc->nid = node_random(allowed_mask);
>
>
> This random selection can cause allocations to fall back to distant memory
> even when the nearer demotion target has sufficient free memory, correct?
> Could this also lead to increased promotion latency?
Hi Donet,
Thanks for your questions.
Yes, the random selection could select a distant node and lead to
incresed promotion latency.
I just realized that the the fallback allocation should not weighted
by a single metric, such as node distance, capacity, free space.
We need a thoroughly study before changing alloc_demote_folio().
Best,
Bing
next prev parent reply other threads:[~2026-01-09 23:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-07 7:28 [PATCH v1 0/2] mm/vmscan: optimize preferred target demotion node selection Bing Jiao
2026-01-07 7:28 ` [PATCH v1 1/2] mm/vmscan: balance demotion allocation in alloc_demote_folio() Bing Jiao
2026-01-08 12:44 ` Donet Tom
2026-01-09 23:45 ` Bing Jiao [this message]
2026-01-10 0:52 ` Joshua Hahn
2026-01-07 7:28 ` [PATCH v1 2/2] mm/vmscan: select the closest perferred node in demote_folio_list() Bing Jiao
2026-01-07 17:39 ` [PATCH v1 0/2] mm/vmscan: optimize preferred target demotion node selection Andrew Morton
2026-01-07 17:46 ` Joshua Hahn
2026-01-08 6:03 ` Bing Jiao
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=aWGTNfrLBhCM3_-9@google.com \
--to=bingjiao@google.com \
--cc=akpm@linux-foundation.org \
--cc=axelrasmussen@google.com \
--cc=david@kernel.org \
--cc=donettom@linux.ibm.com \
--cc=hannes@cmpxchg.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lorenzo.stoakes@oracle.com \
--cc=mhocko@kernel.org \
--cc=shakeel.butt@linux.dev \
--cc=weixugc@google.com \
--cc=yuanchu@google.com \
--cc=zhengqi.arch@bytedance.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