From: NeilBrown <neilb@suse.de>
To: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org, axboe@kernel.dk, shli@fusionio.com
Subject: Re: [patch 1/4] raid1: directly dispatch write request if no bitmap
Date: Thu, 24 May 2012 13:51:17 +1000 [thread overview]
Message-ID: <20120524135117.238b2ed9@notabene.brown> (raw)
In-Reply-To: <20120524033126.GA1172@kernel.org>
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On Thu, 24 May 2012 11:31:26 +0800 Shaohua Li <shli@kernel.org> wrote:
> On Thu, May 24, 2012 at 01:09:12PM +1000, NeilBrown wrote:
> > Not necessarily. It might queue it:
> > if (current->bio_list) {
> > bio_list_add(current->bio_list, bio);
> > return;
> > }
>
> Ah, yes. Looks we can workaround it to increase bioset entry number to
> raid_disks*2. There isn't too much memory wasted with it.
No, that doesn't work. There might be raid_disk*2 separate threads which
have each allocated on entry from the pool, and then they all block waiting
for another.
Adding the pool can change the probability of a deadlock but not the
possibility.
NeilBrown
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next prev parent reply other threads:[~2012-05-24 3:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 7:26 [patch 0/4] MD: improve raid1/10 write performance for fast storage Shaohua Li
2012-05-23 7:26 ` [patch 1/4] raid1: directly dispatch write request if no bitmap Shaohua Li
2012-05-24 2:21 ` NeilBrown
2012-05-24 2:54 ` Shaohua Li
2012-05-24 3:09 ` NeilBrown
2012-05-24 3:31 ` Shaohua Li
2012-05-24 3:51 ` NeilBrown [this message]
2012-05-23 7:26 ` [patch 2/4] raid1: percpu dispatch for write request if bitmap supported Shaohua Li
2012-05-24 3:34 ` NeilBrown
2012-05-24 5:17 ` Shaohua Li
2012-05-24 5:34 ` NeilBrown
2012-05-24 5:50 ` Shaohua Li
2012-05-23 7:26 ` [patch 3/4] raid10: directly dispatch write request if no bitmap Shaohua Li
2012-05-23 7:26 ` [patch 4/4] raid10: percpu dispatch for write request if bitmap supported Shaohua Li
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