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From: Dennis Zhou <dennis@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Roman Gushchin <guro@fb.com>, 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 22:01:33 +0000	[thread overview]
Message-ID: <YMvGPWHY993l3OYj@google.com> (raw)
In-Reply-To: <YMuo55c9QM91pc9p@casper.infradead.org>

Hello,

On Thu, Jun 17, 2021 at 08:56:23PM +0100, Matthew Wilcox wrote:
> 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:

At this point it's just to keep the code consistent.

> 
>  * 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.
> 

This is related to background work done via a workqueue not in process
context. I'll take a look at cleaning up the documentation in the
future.

Thanks,
Dennis

  reply	other threads:[~2021-06-17 22:01 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
2021-06-17 22:01   ` Dennis Zhou [this message]
2021-06-18  2:53 ` Dennis Zhou

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