From: Vlastimil Babka <vbabka@suse.cz>
To: Christoph Hellwig <hch@infradead.org>
Cc: klourencodev@gmail.com, linux-mm@kvack.org, akpm@linux-foundation.org
Subject: Re: [PATCH] mm/mempool.c: set @elems slots to NULL once freed
Date: Tue, 6 Jan 2026 09:00:21 +0100 [thread overview]
Message-ID: <e1f271a2-6215-4d16-b17b-45ff8548f8b3@suse.cz> (raw)
In-Reply-To: <aVyqPfnVtdAM4HYY@infradead.org>
On 1/6/26 07:22, Christoph Hellwig wrote:
> On Mon, Jan 05, 2026 at 05:46:47PM +0100, Vlastimil Babka wrote:
>> On 12/24/25 00:10, klourencodev@gmail.com wrote:
>> > From: Kevin Lourenco <klourencodev@gmail.com>
>> >
>> > This is documented in the function comment as "...and sets their
>> > slots in @elems to NULL.", but it was not followed.
>> >
>> > We need to follow the NULL assignment, because elements newly returned
>> > to the pool must not be touched under any circumstances by the user.
>>
>> Well alternatively we could update the comment if no user needs to rely on
>> this. Since it was modeled after __alloc_pages_bulk()/release_pages() and
>> release_pages() doesn't do this, we could also avoid it for perf reasons.
>> Christoph, what do you think?
>
> Not sure. I hate the magic null skipping behavior in
> __alloc_pages_bulk()/release_pages(), but given that we try to stay
> compatible it might be best to do this.
Well but release_pages() is null skipping but not NULL creating?
next prev parent reply other threads:[~2026-01-06 8:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-23 23:10 klourencodev
2025-12-23 23:47 ` Vlastimil Babka
2026-01-05 16:46 ` Vlastimil Babka
2026-01-06 6:22 ` Christoph Hellwig
2026-01-06 8:00 ` Vlastimil Babka [this message]
2026-01-06 8:09 ` Christoph Hellwig
2026-01-08 14:15 ` Christoph Hellwig
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