From: Mike Snitzer <snitzer@redhat.com>
To: Hannes Reinecke <hare@suse.de>
Cc: dm-devel@redhat.com, Alasdair Kergon <agk@redhat.com>
Subject: Re: dm: do not call dm_sync_table() when creating new devices
Date: Wed, 5 Nov 2014 09:15:43 -0500 [thread overview]
Message-ID: <20141105141542.GB14285@redhat.com> (raw)
In-Reply-To: <1415194550-121498-1-git-send-email-hare@suse.de>
On Wed, Nov 05 2014 at 8:35am -0500,
Hannes Reinecke <hare@suse.de> wrote:
> When creating new devices dm_sync_table() calls
> synchronize_rcu_expedited(), causing _all_ pending
> RCU pointers to be flushed. This causes a latency
> overhead especially noticeable when creating lots
> of devices.
> And all of this is pointless as there are no old
> maps to be disconnected, and hence no stale pointers
> which would need to be cleared up.
>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
Looks good, I'll get it staged for 3.19 (will need to be rebased on the
linux-dm.git 'dm-for-3.19' branch given the suspend related refactoring
there, but I'll take care of it as needed).
next prev parent reply other threads:[~2014-11-05 14:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-05 13:35 [PATCH] dm: do not call dm_sync_table() when creating new devices Hannes Reinecke
2014-11-05 14:15 ` Mike Snitzer [this message]
2014-11-05 22:16 ` Mikulas Patocka
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