From: Hillf Danton <hdanton@sina.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <frederic@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v2 0/5] Introduce QPW for per-cpu operations (v2)
Date: Wed, 11 Mar 2026 09:18:14 +0800 [thread overview]
Message-ID: <20260311011815.785-1-hdanton@sina.com> (raw)
In-Reply-To: <abBQ40Zkk76Zej8i@tpad>
On Tue, 10 Mar 2026 14:12:03 -0300 Marcelo Tosatti wrote:
> Can you please be more verbose, mindful of lesser cognitive powers ? :-)
>
> Note: i also dislike the added layers (and multiple cases) QPW adds.
>
> But there is precedence with local locks...
>
> Code would be less complex in case spinlocks were added:
>
> 01b44456a7aa7c3b24fa9db7d1714b208b8ef3d8 mm/page_alloc: replace local_lock with normal spinlock
> 4b23a68f953628eb4e4b7fe1294ebf93d4b8ceee mm/page_alloc: protect PCP lists with a spinlock
>
> But people seem to reject that in the basis of performance degradation.
>
Given pcp_spin_lock() cut in 0f21b911011f ("mm/page_alloc: simplify and cleanup
pcp locking"), spin lock works because of trylock and fallback, so it is a special
case instead of a generic boilerplate to follow.
next prev parent reply other threads:[~2026-03-11 1:18 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)
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 [this message]
2026-03-11 7:54 ` Vlastimil Babka
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