From: Michal Hocko <mhocko@suse.com>
To: Kaitao Cheng <kaitao.cheng@linux.dev>
Cc: Dennis Zhou <dennis@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Uladzislau Rezki <urezki@gmail.com>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@gentwo.org>,
Vlastimil Babka <vbabka@kernel.org>,
muchun.song@linux.dev, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Kaitao Cheng <chengkaitao@kylinos.cn>
Subject: Re: [PATCH v3 3/3] mm/percpu: Avoid IO/FS reclaim in backing allocations
Date: Wed, 17 Jun 2026 15:16:50 +0200 [thread overview]
Message-ID: <ajKeQhvsPwjjVLEx@tiehlicka> (raw)
In-Reply-To: <def64c45-bbe0-426a-bba1-9ac9e4db672d@linux.dev>
On Wed 17-06-26 16:56:56, Kaitao Cheng wrote:
[...]
> __GFP_NOFAIL is actually unnecessary here. The main reason is that,
> for now, I have not found any in-kernel callers that pass __GFP_NOFAIL
> to pcpu_alloc_noprof() or its wrapper functions. The reason I added
> __GFP_NOFAIL was to address the issue reported by sashiko, and I
> provided a detailed clarification in the link below.
>
> https://lore.kernel.org/all/3de3a89b-92f0-4cd2-9f41-8e853eae4e78@linux.dev/
>
> We should probably revert the current patch back to the v2 version,
> and then add some comments explaining why pcpu_alloc_noprof() must
> not be passed the __GFP_NOFAIL flag, as suggested by Andrew Morton.
Do not add support for nofail semantic until there is a clear demand for
it. Supporting this semantic is a big commitment and it shouldn't be
done without a very good usecase in mind.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2026-06-17 13:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-12 2:26 [PATCH v3 0/3] mm/percpu: Fix possible NOFS/NOIO reclaim recursion Kaitao Cheng
2026-06-12 2:26 ` [PATCH v3 1/3] mm/vmalloc: honor GFP constraints in pcpu_get_vm_areas() Kaitao Cheng
2026-06-17 6:02 ` Dennis Zhou
2026-06-12 2:26 ` [PATCH v3 2/3] mm/percpu: honor GFP constraints when populating chunks Kaitao Cheng
2026-06-17 6:29 ` Dennis Zhou
2026-06-12 2:26 ` [PATCH v3 3/3] mm/percpu: Avoid IO/FS reclaim in backing allocations Kaitao Cheng
2026-06-17 6:53 ` Dennis Zhou
2026-06-17 8:56 ` Kaitao Cheng
2026-06-17 13:16 ` Michal Hocko [this message]
2026-06-17 7:03 ` [PATCH v3 0/3] mm/percpu: Fix possible NOFS/NOIO reclaim recursion Dennis Zhou
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