From: "liyiming" <liyiming@nrchpc.ac.cn>
To: Neil Brown <neilb@suse.de>
Cc: "linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>
Subject: Does the md codes can work well under SMP?
Date: Tue, 12 Dec 2006 15:23:59 +0800 [thread overview]
Message-ID: <200612121523597963092@nrchpc.ac.cn> (raw)
These days I devoted to reading md codes in 2.6.12_r11
I have noticed that you applied two different locking strategy in these two functions:
end_read_request:
if (uptodate) {
set_bit(R5_UPTODATE, &sh->dev[i].flags);
} else {
md_error(conf->mddev, conf->disks[i].rdev);
clear_bit(R5_UPTODATE, &sh->dev[i].flags);
}
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
clear_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(STRIPE_HANDLE, &sh->state);
release_stripe(sh);
end_write_request:
spin_lock_irqsave(&conf->device_lock, flags);
if (!uptodate)
md_error(conf->mddev, conf->disks[i].rdev);
rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
clear_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(STRIPE_HANDLE, &sh->state);
__release_stripe(conf, sh);
spin_unlock_irqrestore(&conf->device_lock, flags);
if these two function excuting on different CPU, the spin lock can work well? and why?
--------------
liyiming
2006-12-12
reply other threads:[~2006-12-12 7:23 UTC|newest]
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