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: Wed, 11 Mar 2026 08:58:05 +0100 [thread overview]
Message-ID: <26662caf-de09-4f13-b374-dc7f879b7829@kernel.org> (raw)
In-Reply-To: <20260302155105.214878062@redhat.com>
On 3/2/26 16:49, Marcelo Tosatti wrote:
> Index: linux/Documentation/admin-guide/kernel-parameters.txt
> ===================================================================
> --- linux.orig/Documentation/admin-guide/kernel-parameters.txt
> +++ linux/Documentation/admin-guide/kernel-parameters.txt
> @@ -2840,6 +2840,16 @@ Kernel parameters
>
> The format of <cpu-list> is described above.
>
> + qpw= [KNL,SMP] Select a behavior on per-CPU resource sharing
> + and remote interference mechanism on a kernel built with
> + CONFIG_QPW.
> + Format: { "0" | "1" }
> + 0 - local_lock() + queue_work_on(remote_cpu)
> + 1 - spin_lock() for both local and remote operations
> +
> + Selecting 1 may be interesting for systems that want
> + to avoid interruption & context switches from IPIs.
Requiring a new boot option is always a nuissance. The cpu isolation is
AFAIK difficult enough to setup already. Could the default be that qpw will
auto-enable if there are isolated cpus configured? The option could still be
useful for overriding that automatic decision to both 0 and 1 for testing
etc, but not requried for the expected usecase?
next prev parent reply other threads:[~2026-03-11 7:58 UTC|newest]
Thread overview: 32+ 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)
2026-03-03 16:02 ` Marcelo Tosatti
2026-03-08 18:00 ` Leonardo Bras
2026-03-09 10:14 ` Vlastimil Babka (SUSE)
2026-03-11 0:16 ` Leonardo Bras
2026-03-11 7:58 ` Vlastimil Babka (SUSE) [this message]
2026-03-15 17:37 ` Leonardo Bras
2026-03-16 10:55 ` Vlastimil Babka (SUSE)
2026-03-23 0:51 ` Leonardo Bras
2026-03-13 21:55 ` Frederic Weisbecker
2026-03-15 18:10 ` Leonardo Bras
2026-03-17 13:33 ` Frederic Weisbecker
2026-03-23 1:38 ` Leonardo Bras
2026-03-24 11:54 ` Frederic Weisbecker
2026-03-24 22:06 ` Leonardo Bras
2026-03-23 14:36 ` Marcelo Tosatti
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
2026-03-08 18:02 ` Leonardo Bras
2026-03-03 12:07 ` Vlastimil Babka (SUSE)
2026-03-05 16:55 ` Frederic Weisbecker
2026-03-06 1:47 ` Marcelo Tosatti
2026-03-10 21:34 ` Frederic Weisbecker
2026-03-10 17:12 ` Marcelo Tosatti
2026-03-10 22:14 ` Frederic Weisbecker
2026-03-11 1:18 ` Hillf Danton
2026-03-11 7:54 ` Vlastimil Babka
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