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From: Matthew Wilcox <willy@infradead.org>
To: Roman Gushchin <guro@fb.com>
Cc: Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
	Christoph Lameter <cl@linux.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] percpu: optimize locking in pcpu_balance_workfn()
Date: Thu, 17 Jun 2021 20:56:23 +0100	[thread overview]
Message-ID: <YMuo55c9QM91pc9p@casper.infradead.org> (raw)
In-Reply-To: <20210617190322.3636731-1-guro@fb.com>

On Thu, Jun 17, 2021 at 12:03:22PM -0700, Roman Gushchin wrote:
> +++ b/mm/percpu.c
> @@ -1980,6 +1980,9 @@ void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
>   * If empty_only is %false, reclaim all fully free chunks regardless of the
>   * number of populated pages.  Otherwise, only reclaim chunks that have no
>   * populated pages.
> + *
> + * CONTEXT:
> + * pcpu_lock (can be dropped temporarily)
>   */

What's the shouting all about?  I would write it like this:

 * Context: Process context.  Caller must hold pcpu_lock with interrupts
 * disabled.  This function may drop the lock and re-enable interrupts if
 * it needs to sleep, but will return with the lock held and interrupts
 * disabled.



  reply	other threads:[~2021-06-17 19:56 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-17 19:03 [PATCH v2] percpu: optimize locking in pcpu_balance_workfn() Roman Gushchin
2021-06-17 19:56 ` Matthew Wilcox [this message]
2021-06-17 22:01   ` Dennis Zhou
2021-06-18  2:53 ` Dennis Zhou

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