From: Christoph Hellwig <hch@infradead.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: klourencodev@gmail.com, linux-mm@kvack.org,
Christoph Hellwig <hch@infradead.org>,
akpm@linux-foundation.org
Subject: Re: [PATCH] mm/mempool.c: set @elems slots to NULL once freed
Date: Mon, 5 Jan 2026 22:22:53 -0800 [thread overview]
Message-ID: <aVyqPfnVtdAM4HYY@infradead.org> (raw)
In-Reply-To: <07c4f991-ae41-456d-8e7f-287bf8676c9e@suse.cz>
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.
next prev parent reply other threads:[~2026-01-06 6:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-23 23:10 [PATCH] mm/mempool.c: set @elems slots to NULL once freed klourencodev
2025-12-23 23:47 ` Vlastimil Babka
2026-01-05 16:46 ` Vlastimil Babka
2026-01-06 6:22 ` Christoph Hellwig [this message]
2026-01-06 8:00 ` Vlastimil Babka
2026-01-06 8:09 ` Christoph Hellwig
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