From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Harry Yoo (Oracle)" <harry@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Vlastimil Babka" <vbabka@kernel.org>
Cc: "Christoph Lameter" <cl@gentwo.org>,
"David Rientjes" <rientjes@google.com>,
"Roman Gushchin" <roman.gushchin@linux.dev>,
"Hao Li" <hao.li@linux.dev>,
"Alexei Starovoitov" <ast@kernel.org>,
"Uladzislau Rezki" <urezki@gmail.com>,
"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>, "Zqiang" <qiang.zhang@linux.dev>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Lai Jiangshan" <jiangshanlai@gmail.com>, <rcu@vger.kernel.org>,
<linux-mm@kvack.org>
Subject: Re: [PATCH 7/8] mm/slab: introduce deferred submission of rcu sheaves
Date: Tue, 21 Apr 2026 15:51:02 -0700 [thread overview]
Message-ID: <DHZ78L9HZ1YE.JY63DXXMN9NF@gmail.com> (raw)
In-Reply-To: <20260416091022.36823-8-harry@kernel.org>
On Thu Apr 16, 2026 at 2:10 AM PDT, Harry Yoo (Oracle) wrote:
> Instead of falling back when the rcu sheaf becomes full, implement
> deferred submission of rcu sheaves. If kfree_rcu_sheaf() is invoked
> by kfree_rcu_nolock() (!allow_spin) and IRQs are disabled, the CPU might
> be in the middle of call_rcu() and thus defer call_rcu() with irq_work.
>
> Submit all deferred RCU sheaves to call_rcu() before calling
> rcu_barrier() to ensure the promise of kvfree_rcu_barrier().
>
> An alternative approach could be to implement this in the RCU subsystem,
> tracking if it's safe to call call_rcu() and allowing falling back to
> deferred call_rcu() at the cost of more expensive rcu_barrier() calls.
Yeah. call_rcu_nolock() will be really handy here and in other places.
When you respin pls pick some tree that sashiko knows about.
So it can apply it all and review it all.
Currently it reviewed only patch 1 and failed to apply the most interesting 4+
https://sashiko.dev/#/patchset/20260416091022.36823-1-harry%40kernel.org
next prev parent reply other threads:[~2026-04-21 22:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-16 9:10 [RFC PATCH v2 0/8] kvfree_rcu() improvements Harry Yoo (Oracle)
2026-04-16 9:10 ` [PATCH 1/8] mm/slab: introduce k[v]free_rcu() with struct rcu_ptr Harry Yoo (Oracle)
2026-04-16 9:10 ` [PATCH 2/8] fs/dcache: use rcu_ptr instead of rcu_head for external names Harry Yoo (Oracle)
2026-04-21 20:21 ` Al Viro
2026-04-22 1:16 ` Harry Yoo (Oracle)
2026-04-16 9:10 ` [PATCH 3/8] mm/slab: move kfree_rcu_cpu[_work] definitions Harry Yoo (Oracle)
2026-04-16 9:10 ` [PATCH 4/8] mm/slab: introduce kfree_rcu_nolock() Harry Yoo (Oracle)
2026-04-21 22:46 ` Alexei Starovoitov
2026-04-21 23:10 ` Paul E. McKenney
2026-04-21 23:14 ` Alexei Starovoitov
2026-04-16 9:10 ` [PATCH 5/8] mm/slab: make kfree_rcu_nolock() work with sheaves Harry Yoo (Oracle)
2026-04-16 9:10 ` [PATCH 6/8] mm/slab: wrap rcu sheaf handling with ifdef Harry Yoo (Oracle)
2026-04-16 9:10 ` [PATCH 7/8] mm/slab: introduce deferred submission of rcu sheaves Harry Yoo (Oracle)
2026-04-21 22:51 ` Alexei Starovoitov [this message]
2026-04-16 9:10 ` [PATCH 8/8] lib/tests/slub_kunit: add a test case for kfree_rcu_nolock() Harry Yoo (Oracle)
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