From: Borislav Petkov <bp@alien8.de>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com,
mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org,
tglx@linutronix.de, david@redhat.com, ast@kernel.org,
linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 2/2] mm/page_alloc: Fix race condition in unaccepted memory handling
Date: Tue, 6 May 2025 14:43:41 +0200 [thread overview]
Message-ID: <20250506124341.GDaBoD_cYkXsnTmRdj@fat_crate.local> (raw)
In-Reply-To: <20250506112509.905147-3-kirill.shutemov@linux.intel.com>
On Tue, May 06, 2025 at 02:25:09PM +0300, Kirill A. Shutemov wrote:
> The page allocator tracks the number of zones that have unaccepted
> memory using static_branch_enc/dec() and uses that static branch in hot
> paths to determine if it needs to deal with unaccepted memory.
>
> Borisal and Thomas pointed out that the tracking is racy operations on
Boris or Borislav would be nice.
> static_branch are not serialized against adding/removing unaccepted pages
> to/from the zone.
Also, that sentence needs massaging.
> The effect of this static_branch optimization is only visible on
> microbenchmark.
>
> Instead of adding more complexity around it, remove it altogether.
Yah, good idea.
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Fixes: dcdfdd40fa82 ("mm: Add support for unaccepted memory")
> Link: https://lore.kernel.org/all/20250506092445.GBaBnVXXyvnazly6iF@fat_crate.local
> Reported-by: Borislav Petkov <bp@alien8.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Thx for the quick fix.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next parent reply other threads:[~2025-05-06 12:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20250506112509.905147-1-kirill.shutemov@linux.intel.com>
[not found] ` <20250506112509.905147-3-kirill.shutemov@linux.intel.com>
2025-05-06 12:43 ` Borislav Petkov [this message]
[not found] ` <20250506112509.905147-2-kirill.shutemov@linux.intel.com>
2025-05-06 13:20 ` [PATCH 1/2] mm/page_alloc: Ensure try_alloc_pages() plays well with unaccepted memory Brendan Jackman
2025-05-06 13:34 ` Kirill A. Shutemov
2025-05-07 15:27 ` Brendan Jackman
2025-05-06 17:18 ` Alexei Starovoitov
2025-05-06 19:00 ` Kirill A. Shutemov
2025-05-06 22:05 ` Alexei Starovoitov
2025-05-07 11:13 ` Kirill A. Shutemov
2025-05-07 0:00 ` Andrew Morton
2025-05-07 11:31 ` Kirill A. Shutemov
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