From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: Marcelo Tosatti <mtosatti@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.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>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
Leonardo Bras <leobras.c@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <longman@redhat.com>,
Boqun Feun <boqun.feng@gmail.com>,
Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [PATCH v2 2/5] Introducing qpw_lock() and per-cpu queue & flush work
Date: Tue, 3 Mar 2026 13:03:36 +0100 [thread overview]
Message-ID: <682380ba-c8f3-4023-928c-2152e934f8db@kernel.org> (raw)
In-Reply-To: <20260302155105.214878062@redhat.com>
On 3/2/26 16:49, Marcelo Tosatti wrote:
> +#define local_qpw_lock(lock) \
> + do { \
> + if (static_branch_maybe(CONFIG_QPW_DEFAULT, &qpw_sl)) { \
> + migrate_disable(); \
Have you considered using migrate_disable() on PREEMPT_RT and
preempt_disable() on !PREEMPT_RT since it's cheaper? It's what the pcp
locking in mm/page_alloc.c does, for that reason. It should reduce the
overhead with qpw=1 on !PREEMPT_RT.
> + spin_lock(this_cpu_ptr(lock.sl)); \
> + } else \
> + local_lock(lock.ll); \
> + } while (0)
> +
next prev parent reply other threads:[~2026-03-03 12:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-02 15:49 [PATCH v2 0/5] Introduce QPW for per-cpu operations (v2) Marcelo Tosatti
2026-03-02 15:49 ` [PATCH v2 1/5] slab: distinguish lock and trylock for sheaf_flush_main() Marcelo Tosatti
2026-03-02 15:49 ` [PATCH v2 2/5] Introducing qpw_lock() and per-cpu queue & flush work Marcelo Tosatti
2026-03-03 12:03 ` Vlastimil Babka (SUSE) [this message]
2026-03-02 15:49 ` [PATCH v2 3/5] mm/swap: move bh draining into a separate workqueue Marcelo Tosatti
2026-03-02 15:49 ` [PATCH v2 4/5] swap: apply new queue_percpu_work_on() interface Marcelo Tosatti
2026-03-02 15:49 ` [PATCH v2 5/5] slub: " Marcelo Tosatti
2026-03-03 11:15 ` [PATCH v2 0/5] Introduce QPW for per-cpu operations (v2) Frederic Weisbecker
2026-03-03 12:07 ` Vlastimil Babka (SUSE)
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