From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Huacai Chen <chenhuacai@loongson.cn>
Cc: Sasha Levin <sashal@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
Xuerui Wang <kernel@xen0n.name>,
stable@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, loongarch@lists.linux.dev,
Zi Yan <ziy@nvidia.com>, Huang Ying <ying.huang@intel.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH for 6.6] mm/migrate: correct nr_failed in migrate_pages_sync()
Date: Tue, 13 May 2025 10:12:20 +0200 [thread overview]
Message-ID: <2025051311-retaining-subtract-20c9@gregkh> (raw)
In-Reply-To: <20250513080521.252543-1-chenhuacai@loongson.cn>
On Tue, May 13, 2025 at 04:05:21PM +0800, Huacai Chen wrote:
> From: Zi Yan <ziy@nvidia.com>
>
> nr_failed was missing the large folio splits from migrate_pages_batch()
> and can cause a mismatch between migrate_pages() return value and the
> number of not migrated pages, i.e., when the return value of
> migrate_pages() is 0, there are still pages left in the from page list.
> It will happen when a non-PMD THP large folio fails to migrate due to
> -ENOMEM and is split successfully but not all the split pages are not
> migrated, migrate_pages_batch() would return non-zero, but
> astats.nr_thp_split = 0. nr_failed would be 0 and returned to the caller
> of migrate_pages(), but the not migrated pages are left in the from page
> list without being added back to LRU lists.
>
> Fix it by adding a new nr_split counter for large folio splits and adding
> it to nr_failed in migrate_page_sync() after migrate_pages_batch() is
> done.
>
> Link: https://lkml.kernel.org/r/20231017163129.2025214-1-zi.yan@sent.com
> Fixes: 2ef7dbb26990 ("migrate_pages: try migrate in batch asynchronously firstly")
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> Acked-by: Huang Ying <ying.huang@intel.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
> This patch has a Fixes tag and should be backported to 6.6, I don't know
> why hasn't bakported.
>
What is the upstream git id for this commit?
prev parent reply other threads:[~2025-05-13 8:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-13 8:05 Huacai Chen
2025-05-13 8:11 ` Greg Kroah-Hartman
2025-05-13 8:12 ` Greg Kroah-Hartman [this message]
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=2025051311-retaining-subtract-20c9@gregkh \
--to=gregkh@linuxfoundation.org \
--cc=akpm@linux-foundation.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=chenhuacai@kernel.org \
--cc=chenhuacai@loongson.cn \
--cc=david@redhat.com \
--cc=kernel@xen0n.name \
--cc=linux-mm@kvack.org \
--cc=loongarch@lists.linux.dev \
--cc=sashal@kernel.org \
--cc=stable@vger.kernel.org \
--cc=willy@infradead.org \
--cc=ying.huang@intel.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