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From: NeilBrown <neilb@suse.de>
To: majianpeng <majianpeng@gmail.com>
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: md:Add break if find.
Date: Wed, 14 Mar 2012 13:06:15 +1100	[thread overview]
Message-ID: <20120314130615.7e5dbd42@notabene.brown> (raw)
In-Reply-To: <201203131328071710700@gmail.com>

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On Tue, 13 Mar 2012 13:28:12 +0800 "majianpeng" <majianpeng@gmail.com> wrote:

> >From 6e04c2374db7fc34ccbf9f37f85e735a349c816c Mon Sep 17 00:00:00 2001
> From: majianpeng <majianpeng@gmail.com>
> Date: Tue, 13 Mar 2012 13:26:25 +0800
> Subject: [PATCH] md:Add break if find.
> 
> 
> Signed-off-by: majianpeng <majianpeng@gmail.com>
> ---
>  drivers/md/raid5.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 360f2b9..e05d9e5 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -4369,8 +4369,10 @@ static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int
>  	 * recovery aborts.
>  	 */
>  	for (i = 0; i < conf->raid_disks; i++)
> -		if (conf->disks[i].rdev == NULL)
> +		if (conf->disks[i].rdev == NULL) {
>  			still_degraded = 1;
> +			break;
> +		}
>  
>  	bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
>  

Thanks - however I don't think I'll apply this one.

It is a micro optimisation which only improve an uncommon case a little,
but it makes the source code long and the generated machine code longer (by
32 bytes on x86_64).
So I don't really think it is a win.

Thanks,
NeilBrown


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  reply	other threads:[~2012-03-14  2:06 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-13  5:28 md:Add break if find majianpeng
2012-03-14  2:06 ` NeilBrown [this message]
2012-03-14  2:30 ` kedacomkernel

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