From: "Simon Wang (王传国)" <wangchuanguo@inspur.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"mhiramat@kernel.org" <mhiramat@kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: migrate: restore the nmask after successfully allocating on the target node
Date: Tue, 1 Apr 2025 01:06:32 +0000 [thread overview]
Message-ID: <80bbb67e8d524aad97fecc99d1eebd52@inspur.com> (raw)
>
> On Wed, Mar 26, 2025 at 11:12:18AM +0800, wangchuanguo wrote:
> > If memory is successfully allocated on the target node and the
> > function directly returns without value restore for nmask, non-first
> > migration operations in migrate_pages() by again label may ignore the
> > nmask settings, thereby allowing new memory allocations for migration
> > on any node.
> >
> > Signed-off-by: wangchuanguo <wangchuanguo@inspur.com>
>
> Unless I am missing something this looks reasonable, but I whonder why
> nobody noticed it before.
> It is a path that should be pretty exercised.
>
>
> --
> Oscar Salvador
> SUSE Labs
I tested it, and even when the nmask is set to all zeros, memory allocation still occurs on other nodes.
I suspect this is because the bug expands the range of eligible nodes for memory allocation instead of causing allocation failures, which is why it has gone unnoticed.
next reply other threads:[~2025-04-01 1:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-01 1:06 Simon Wang (王传国) [this message]
-- strict thread matches above, loose matches on Subject: below --
2025-04-01 0:48 Simon Wang (王传国)
2025-03-26 5:54 Simon Wang (王传国)
2025-03-28 13:41 ` Oscar Salvador
2025-03-26 3:12 wangchuanguo
2025-03-26 3:28 ` Matthew Wilcox
2025-03-28 13:44 ` Oscar Salvador
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