From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: akpm@linux-foundation.org, david@kernel.org, liam@infradead.org,
vbabka@kernel.org, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, qi.zheng@linux.dev, jack@suse.cz,
pfalcato@suse.de, ayushr@modal.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: memory: fix truncation removing mapped folios
Date: Fri, 9 Oct 2026 13:00:52 +0100 [thread overview]
Message-ID: <asjXJZap53yJWMYi@gremlin> (raw)
In-Reply-To: <0d2a1809fa1cfc22ad3df26ec28b2d30e5cdf3bd.1791540483.git.baolin.wang@linux.alibaba.com>
On Fri, Oct 09, 2026 at 06:12:03PM +0800, Baolin Wang wrote:
> diff --git a/mm/memory.c b/mm/memory.c
> index 1f5d5f7d39cd..0272217ad7b0 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2044,16 +2053,10 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
> * to ensure they are still none, thereby preventing the pte entries
> * from being repopulated by another thread.
> */
> - if (can_reclaim_pt && direct_reclaim && addr == end)
> + if (can_reclaim_pt && direct_reclaim && addr == end) {
> + /* rmap changes need to be observed before e.g PTEs get zapped. */
> + smp_wmb();
What does this pair with? You should always say what in the comment.
rmb/wmb are generally not needed vs. acquire/release. Are you sure a wmb is
right here?
--
Cheers, Lorenzo
next prev parent reply other threads:[~2026-10-09 12:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-09 10:12 [PATCH] mm: memory: fix truncation removing mapped folios Baolin Wang
2026-10-09 12:00 ` Lorenzo Stoakes (ARM) [this message]
2026-10-09 13:36 ` Pedro Falcato
2026-10-09 13:53 ` Baolin Wang
2026-10-09 17:01 ` Pedro Falcato
2026-10-10 2:56 ` Baolin Wang
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