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 5/9] mm/slab: extend deferred free mechanism to handle rcu sheaves
Date: Tue, 16 Jun 2026 15:03:54 +0200 [thread overview]
Message-ID: <7a5c9346-cda5-4cff-907d-6f5acadd4d56@kernel.org> (raw)
In-Reply-To: <20260615-kfree_rcu_nolock-v3-5-70a54f3775bb@kernel.org>
On 6/15/26 13:05, Harry Yoo (Oracle) wrote:
> __kfree_rcu_sheaf() cannot invoke call_rcu() when spinning is not
> allowed and IRQs are disabled. To relax the limitation, extend the
> deferred free fallback so that a full rcu sheaf can be submitted to
> call_rcu() via the existing IRQ work.
>
> Since the deferred mechanism does more than deferred free of objects,
> rename the struct to deferred_percpu_work and adjust names accordingly.
>
> When a sheaf is queued on an IRQ work, it is detached from
> pcs->rcu_free but call_rcu() is not invoked until the irq_work runs.
> To keep the kvfree_rcu barrier's promise, call irq_work_sync() on each
> CPU before calling rcu_barrier().
>
> In the meantime, remove the TODO item as apparently there is no simple
> and effective way to achieve that.
>
> Suggested-by: Alexei Starovoitov <ast@kernel.org>
> Signed-off-by: Harry Yoo (Oracle) <harry@kernel.org>
LGTM.
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
next prev parent reply other threads:[~2026-06-16 13:04 UTC|newest]
Thread overview: 53+ 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 11:14 ` sashiko-bot
2026-06-15 12:58 ` Harry Yoo
2026-06-15 20:01 ` Alexei Starovoitov
2026-06-16 5:23 ` Harry Yoo
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 11:25 ` sashiko-bot
2026-06-15 20:04 ` Alexei Starovoitov
2026-06-16 6:57 ` Vlastimil Babka (SUSE)
2026-06-24 13:41 ` Pedro Falcato
2026-06-29 7:34 ` Harry Yoo
2026-06-29 8:20 ` Harry Yoo
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)
2026-06-15 11:24 ` sashiko-bot
2026-06-16 7:55 ` Vlastimil Babka (SUSE)
2026-06-16 9:20 ` Vlastimil Babka (SUSE)
2026-06-17 5:32 ` Harry Yoo
2026-06-17 5:58 ` Vlastimil Babka (SUSE)
2026-06-24 14:28 ` Pedro Falcato
2026-06-29 8:01 ` Harry Yoo
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 11:25 ` sashiko-bot
2026-06-16 9:51 ` Vlastimil Babka (SUSE)
2026-06-24 14:30 ` Pedro Falcato
2026-06-29 8:19 ` Harry Yoo
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 11:24 ` sashiko-bot
2026-06-16 13:03 ` Vlastimil Babka (SUSE) [this message]
2026-06-24 14:37 ` Pedro Falcato
2026-06-15 11:06 ` [PATCH for-next v3 6/9] mm/slab: allow kfree_rcu_sheaf() on PREEMPT_RT Harry Yoo (Oracle)
2026-06-15 11:19 ` sashiko-bot
2026-06-16 17:24 ` Vlastimil Babka (SUSE)
2026-06-17 5:14 ` Harry Yoo
2026-06-17 5:38 ` Vlastimil Babka (SUSE)
2026-06-17 20:40 ` Paul E. McKenney
2026-06-18 12:46 ` Harry Yoo
2026-06-18 16:26 ` Paul E. McKenney
2026-06-15 11:06 ` [PATCH for-next v3 7/9] mm/slab: introduce kfree_rcu_nolock() Harry Yoo (Oracle)
2026-06-15 11:22 ` sashiko-bot
2026-06-16 17:28 ` Vlastimil Babka (SUSE)
2026-06-21 0:29 ` XIAO WU
2026-06-22 5:28 ` Harry Yoo
2026-06-22 14:56 ` XIAO WU
2026-06-25 5:27 ` Harry Yoo
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)
2026-06-15 11:22 ` sashiko-bot
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
2026-06-15 20:28 ` Alexei Starovoitov
2026-06-16 4:57 ` Harry Yoo
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