From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>,
"Harry Yoo" <harry@kernel.org>
Cc: "Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Hocko" <mhocko@kernel.org>,
"Roman Gushchin" <roman.gushchin@linux.dev>,
"Shakeel Butt" <shakeel.butt@linux.dev>,
"Muchun Song" <muchun.song@linux.dev>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Hao Li" <hao.li@linux.dev>, "Christoph Lameter" <cl@gentwo.org>,
"David Rientjes" <rientjes@google.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Clark Williams" <clrkwllms@kernel.org>,
"Steven Rostedt" <rostedt@goodmis.org>, <kernel-team@meta.com>,
<cgroups@vger.kernel.org>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>, <linux-rt-devel@lists.linux.dev>,
"Sashiko" <sashiko-bot@kernel.org>
Subject: Re: [PATCH for-next-fixes v2 4/5] mm/slab: fix a deadlock in memcg_alloc_abort_single()
Date: Wed, 04 Nov 2026 16:46:26 +0000 [thread overview]
Message-ID: <DMMKUQVDEM0N.322USN1ZSYMCU@gmail.com> (raw)
In-Reply-To: <6441429b-eff2-485b-acf3-26c3034910ae@kernel.org>
On Wed, Nov 04, 2026 at 07:35 AM Vlastimil Babka (SUSE) <vbabka@kernel.org> wrote:
>> I don't insist on kfree_nolock() there,
>> but can we try free_to_pcs() before defer_free() ?
>> Like:
>>
>> if (likely(allow_spin))
>> __slab_free(s, slab, object, object, 1, _RET_IP_);
>> else if (!can_free_to_pcs(slab) || !free_to_pcs(s, object, false))
>> defer_free(s, object);
>
> Why not try free_to_pcs with allow_spin as well then, and improve
> memcg_alloc_abort_single() for both contexts?
yep. Even better.
The bulk side does that already.
Like:
if (likely(can_free_to_pcs(slab)) &&
likely(free_to_pcs(s, object, allow_spin)))
return;
if (likely(allow_spin))
__slab_free(s, slab, object, object, 1, _RET_IP_);
else
defer_free(s, object);
?
next prev parent reply other threads:[~2026-11-04 16:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-03 14:47 [PATCH for-next-fixes v2 0/5] memcg,slab: kmalloc_nolock() fixes Harry Yoo (Meta)
2026-11-03 14:47 ` [PATCH for-next-fixes v2 1/5] mm/memcontrol: defer obj_cgroup_release() to irq_work Harry Yoo (Meta)
2026-11-04 11:02 ` Vlastimil Babka (SUSE)
2026-11-04 12:00 ` Harry Yoo
2026-11-03 14:47 ` [PATCH for-next-fixes v2 2/5] mm/slab: handle allow_spin in slab_free_hook() instead of open coding Harry Yoo (Meta)
2026-11-04 13:54 ` Vlastimil Babka (SUSE)
2026-11-03 14:47 ` [PATCH for-next-fixes v2 3/5] mm/slab: call debug_locks and KCSAN checks in kfree_nolock() Harry Yoo (Meta)
2026-11-03 14:47 ` [PATCH for-next-fixes v2 4/5] mm/slab: fix a deadlock in memcg_alloc_abort_single() Harry Yoo (Meta)
2026-11-03 18:40 ` Alexei Starovoitov
2026-11-03 20:21 ` Harry Yoo
2026-11-03 21:11 ` Alexei Starovoitov
2026-11-04 15:35 ` Vlastimil Babka (SUSE)
2026-11-04 16:46 ` Alexei Starovoitov [this message]
2026-11-03 14:47 ` [PATCH for-next-fixes v2 5/5] mm/slab: serialize deferred_work_barrier() Harry Yoo (Meta)
2026-11-04 16:24 ` Vlastimil Babka (SUSE)
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