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Date:   Mon, 8 Aug 2022 09:38:52 -0700
From:   Yury Norov <yury.norov@gmail.com>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     linux-kernel@vger.kernel.org,
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Subject: Re: [PATCH 11/16] time: optimize tick_check_preferred()
Message-ID: <YvE8HGXFDicr/zI5@yury-laptop>
References: <20220718192844.1805158-1-yury.norov@gmail.com>
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On Mon, Aug 08, 2022 at 01:42:54PM +0200, Thomas Gleixner wrote:
> On Sat, Aug 06 2022 at 10:30, Thomas Gleixner wrote:
> > On Mon, Jul 18 2022 at 12:28, Yury Norov wrote:
> >
> >> tick_check_preferred() calls cpumask_equal() even if
> >> curdev->cpumask == newdev->cpumask. Fix it.
> >
> > What's to fix here? It's a pointless operation in a slow path and all
> > your "fix' is doing is to make the code larger.

Pointless operation in a slow path is still pointless.
 
> In fact cpumask_equal() should have the ptr1 == ptr2 check, so you don't
> have to add it all over the place.

This adds to the image size:
add/remove: 1/1 grow/shrink: 24/3 up/down: 507/-46 (461)

The more important, cpumask shouldn't check parameters because this is
an internal function. This whole series point is about adding such checks
under DEBUG_BITMAP config, and not affecting general case.

What about adding cpumask_equal__addr? (Any better name is welcome.)

Thanks,
Yury