linux-kernel - Re: [PATCHv2 1/8] mm: Fix endless reclaim on machines with unaccepted memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAMGD6P0ckHzobW1j2GvqqZ3mNUHCBfP9xM-15s8B6yOfdv8MPg@mail.gmail.com>
Date: Mon, 12 Aug 2024 15:12:50 -0700
From: Jianxiong Gao <jxgao@...gle.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>, "Borislav Petkov (AMD)" <bp@...en8.de>, 
	Mel Gorman <mgorman@...e.de>, Vlastimil Babka <vbabka@...e.cz>, Tom Lendacky <thomas.lendacky@....com>, 
	Mike Rapoport <rppt@...nel.org>, "Matthew Wilcox (Oracle)" <willy@...radead.org>, 
	David Hildenbrand <david@...hat.com>, Johannes Weiner <hannes@...xchg.org>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCHv2 1/8] mm: Fix endless reclaim on machines with unaccepted memory

On Fri, Aug 9, 2024 at 4:49 AM Kirill A. Shutemov
<kirill.shutemov@...ux.intel.com> wrote:
>
> Unaccepted memory is considered unusable free memory, which is not
> counted as free on the zone watermark check. This causes
> get_page_from_freelist() to accept more memory to hit the high
> watermark, but it creates problems in the reclaim path.
>
> The reclaim path encounters a failed zone watermark check and attempts
> to reclaim memory. This is usually successful, but if there is little or
> no reclaimable memory, it can result in endless reclaim with little to
> no progress. This can occur early in the boot process, just after start
> of the init process when the only reclaimable memory is the page cache
> of the init executable and its libraries.
>
> Make unaccepted memory free from watermark check point of view. This way
> unaccepted memory will never be the trigger of memory reclaim.
> Accept more memory in the get_page_from_freelist() if needed.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> Reported-by: Jianxiong Gao <jxgao@...gle.com>
> Acked-by: David Hildenbrand <david@...hat.com>
> Fixes: dcdfdd40fa82 ("mm: Add support for unaccepted memory")
> Cc: stable@...r.kernel.org # v6.5+

Tested-by: Jianxiong Gao <jxgao@...gle.com>
I have verified that the patch fixes the systemd issue reported.