From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: "Harry Yoo (Oracle)" <harry@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Hao Li <hao.li@linux.dev>, Christoph Lameter <cl@gentwo.org>,
David Rientjes <rientjes@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Puranjay Mohan <puranjay@kernel.org>,
Amery Hung <ameryhung@gmail.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Clark Williams <clrkwllms@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun@kernel.org>,
Uladzislau Rezki <urezki@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang@linux.dev>, Pedro Falcato <pfalcato@suse.de>,
Suren Baghdasaryan <surenb@google.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-rt-devel@lists.linux.dev, rcu@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH for-next v3 7/9] mm/slab: introduce kfree_rcu_nolock()
Date: Tue, 16 Jun 2026 19:28:03 +0200 [thread overview]
Message-ID: <26022de8-eea6-4684-bb2d-05419b10d898@kernel.org> (raw)
In-Reply-To: <20260615-kfree_rcu_nolock-v3-7-70a54f3775bb@kernel.org>
On 6/15/26 13:06, Harry Yoo (Oracle) wrote:
> Currently, k[v]free_rcu() cannot be called in unknown context since
> it could lead to a deadlock when called in the middle of k[v]free_rcu().
>
> Make users' lives easier by introducing kfree_rcu_nolock() variant,
> now that kfree_rcu_sheaf() is available on PREEMPT_RT and
> __kfree_rcu_sheaf() handles unknown context.
>
> Unlike k[v]free_rcu(), kfree_rcu_nolock() does not fall back to
> the kvfree_rcu batching when the sheaves path fails, and falls back to
> defer_kfree_rcu() instead. In most cases, the sheaves path is expected
> to succeed and it's unnecessary to add complexity to the existing
> kvfree_rcu batching.
>
> Since defer_kfree_rcu() can be called on caches without sheaves, move
> deferred_work_barrier() and rcu_barrier() outside the branch in
> kvfree_rcu_barrier_on_cache().
>
> Signed-off-by: Harry Yoo (Oracle) <harry@kernel.org>
LGTM, nice.
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
next prev parent reply other threads:[~2026-06-16 21:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-15 11:05 [PATCH for-next v3 0/9] mm/slab: introduce kfree_rcu_nolock() and improve slub_kunit coverage Harry Yoo (Oracle)
2026-06-15 11:05 ` [PATCH for-next v3 1/9] slub_kunit: fall back to SW perf events when HW PMU is not available Harry Yoo (Oracle)
2026-06-15 11:05 ` [PATCH for-next v3 2/9] mm/slab, slub_kunit: register kprobe to trigger _nolock APIs Harry Yoo (Oracle)
2026-06-15 11:05 ` [PATCH for-next v3 3/9] mm/slab: handle the !allow_spin case in kfree_rcu_sheaf() Harry Yoo (Oracle)
[not found] ` <4d7ebcd5-f3b7-4c73-94f1-b7d3ac12a521@kernel.org>
2026-06-17 5:32 ` Harry Yoo
2026-06-17 5:58 ` Vlastimil Babka (SUSE)
2026-06-15 11:05 ` [PATCH for-next v3 4/9] mm/slab: use call_rcu() in unknown context if irqs are enabled Harry Yoo (Oracle)
2026-06-15 11:05 ` [PATCH for-next v3 5/9] mm/slab: extend deferred free mechanism to handle rcu sheaves Harry Yoo (Oracle)
2026-06-15 11:06 ` [PATCH for-next v3 6/9] mm/slab: allow kfree_rcu_sheaf() on PREEMPT_RT Harry Yoo (Oracle)
2026-06-16 17:24 ` Vlastimil Babka (SUSE)
2026-06-17 5:14 ` Harry Yoo
2026-06-17 5:38 ` Vlastimil Babka (SUSE)
2026-06-15 11:06 ` [PATCH for-next v3 7/9] mm/slab: introduce kfree_rcu_nolock() Harry Yoo (Oracle)
2026-06-16 17:28 ` Vlastimil Babka (SUSE) [this message]
2026-06-15 11:06 ` [PATCH for-next v3 8/9] mm/slab: introduce struct kfree_rcu_head and use in kfree_rcu_nolock() Harry Yoo (Oracle)
2026-06-16 17:36 ` Vlastimil Babka (SUSE)
2026-06-15 11:06 ` [PATCH for-next v3 9/9] slub_kunit: extend the test for kfree_rcu_nolock() Harry Yoo (Oracle)
2026-06-16 17:38 ` Vlastimil Babka (SUSE)
2026-06-15 11:43 ` [PATCH for-next v3 0/9] mm/slab: introduce kfree_rcu_nolock() and improve slub_kunit coverage Harry Yoo
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