From: Tejun Heo <tj@kernel.org>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mikulas Patocka <mpatocka@redhat.com>,
linux-kernel@vger.kernel.org, dm-devel@redhat.com,
Alasdair G Kergon <agk@redhat.com>,
Will Drewry <wad@chromium.org>,
Elly Jones <ellyjones@chromium.org>,
Milan Broz <mbroz@redhat.com>,
Olof Johansson <olofj@chromium.org>,
Steffen Klassert <steffen.klassert@secunet.com>,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: workqueues and percpu (was: [PATCH] dm: remake of the verity target)
Date: Fri, 9 Mar 2012 13:20:49 -0800 [thread overview]
Message-ID: <20120309212049.GD24890@google.com> (raw)
In-Reply-To: <20120309211512.GL27051@google.com>
Hello,
On Fri, Mar 09, 2012 at 01:15:12PM -0800, Mandeep Singh Baines wrote:
> In this case, I need the per-cpu data for the duration of calculating
> a cryptographics hash on a 4K page of data. That's a long time to disable
> pre-emption.
How long are we talking about? Tens of microsecs, tens of millisecs?
> I could fix the bug temporarily by adding get/put for the per_cpu data
> but would that be acceptable? I'm not sure what the OK limit is for how
> long one can disable preemption. An alternative fix would be not allow
> CONFIG_VERITY when CONFIG_HOTPLUG_CPU. Once workqueues are fixed, I could
> remove that restriction.
I think the right thing to do for now is to add cpu hotplug notifier
and do flush_work_sync() on the work item. We can later move that
logic into workqueue and remove it from crypto.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-03-09 21:20 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-02 0:33 [PATCH] dm: verity target Mandeep Singh Baines
2012-03-02 16:08 ` Mandeep Singh Baines
2012-03-04 19:18 ` [PATCH] dm: remake of the " Mikulas Patocka
2012-03-04 19:35 ` userspace hashing utility for dm-verity Mikulas Patocka
2012-03-06 21:59 ` [PATCH] dm: remake of the verity target Mandeep Singh Baines
2012-03-08 22:21 ` workqueues and percpu (was: [PATCH] dm: remake of the verity target) Mikulas Patocka
2012-03-08 22:39 ` Andrew Morton
2012-03-08 23:15 ` Tejun Heo
2012-03-08 23:30 ` Andrew Morton
2012-03-09 0:33 ` Tejun Heo
2012-03-09 0:51 ` Tejun Heo
2012-03-09 21:15 ` Mandeep Singh Baines
2012-03-09 21:20 ` Tejun Heo [this message]
2012-03-09 22:06 ` Mandeep Singh Baines
2012-08-14 17:54 ` Tejun Heo
2012-03-13 22:20 ` [PATCH] dm: remake of the verity target Mikulas Patocka
2012-03-14 21:13 ` Will Drewry
2012-03-17 1:16 ` Mikulas Patocka
2012-03-17 3:06 ` Will Drewry
2012-03-14 21:43 ` Mandeep Singh Baines
2012-03-20 15:41 ` Mandeep Singh Baines
2012-03-21 0:54 ` Mikulas Patocka
2012-03-21 3:03 ` Mandeep Singh Baines
2012-03-21 3:11 ` [dm-devel] " Mikulas Patocka
2012-03-21 3:30 ` Mandeep Singh Baines
2012-03-21 3:44 ` Mikulas Patocka
2012-03-21 3:49 ` Mandeep Singh Baines
2012-03-21 17:08 ` Mikulas Patocka
2012-03-21 17:09 ` Mikulas Patocka
2012-03-22 17:41 ` Mandeep Singh Baines
2012-03-22 21:52 ` Mikulas Patocka
2012-03-23 3:15 ` Mandeep Singh Baines
2012-03-24 3:48 ` Mikulas Patocka
2012-03-21 1:10 ` Mikulas Patocka
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