From: Alasdair G Kergon <agk@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Milan Broz <mbroz@redhat.com>, Mike Snitzer <snitzer@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
device-mapper development <dm-devel@redhat.com>,
pedrib@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [dm-devel] DM-CRYPT: Scale to multiple CPUs v3
Date: Sun, 10 Oct 2010 19:17:36 +0100 [thread overview]
Message-ID: <20101010181736.GE28828@agk-dp.fab.redhat.com> (raw)
In-Reply-To: <20101010174454.GA21681@basil.fritz.box>
On Sun, Oct 10, 2010 at 07:44:54PM +0200, Andi Kleen wrote:
> It's not broken AFAIK and it will not perform worse than the original
> single thread work queue.
This is the contentious code:
+ /*
+ * Since we only have a single worker per CPU in extreme
+ * cases there might be nesting (dm-crypt on another dm-crypt)
+ * To avoid deadlock run the work directly then.
+ */
+ cpu = get_cpu();
+ if (per_cpu(io_wq_cpu, cpu) == current && !in_interrupt()) {
+ put_cpu();
+ kcryptd_io(&io->work);
+ return;
+ }
AFAIK Nested dm-crypt is not extreme for some folk who have routine
configurations using it. But if in_interrupt is set how does this code
work for them now compared to how it worked before?
Alasdair
next prev parent reply other threads:[~2010-10-10 18:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-10 11:59 [PATCH] DM-CRYPT: Scale to multiple CPUs v3 Andi Kleen
2010-10-10 12:38 ` [dm-devel] " Milan Broz
2010-10-10 12:53 ` Milan Broz
2010-10-10 13:09 ` Andi Kleen
2010-10-10 13:08 ` Andi Kleen
2010-10-10 15:34 ` Milan Broz
2010-10-10 16:06 ` Andi Kleen
2010-10-10 16:22 ` Mike Snitzer
2010-10-10 16:41 ` Milan Broz
2010-10-10 17:07 ` Mike Snitzer
2010-10-10 18:56 ` [PATCH] Fix double free and use generic private pointer in per-cpu struct Milan Broz
2010-10-14 19:26 ` [dm-devel] " Milan Broz
2010-10-20 14:20 ` [dm-devel] [PATCH] DM-CRYPT: Scale to multiple CPUs v3 Milan Broz
2010-10-20 17:32 ` Alasdair G Kergon
2010-10-10 17:01 ` Alasdair G Kergon
2010-10-10 17:44 ` Andi Kleen
2010-10-10 18:17 ` Alasdair G Kergon [this message]
2010-10-10 18:48 ` Alasdair G Kergon
2010-10-10 18:51 ` [dm-devel] " Andi Kleen
2010-10-10 19:07 ` Alasdair G Kergon
2010-10-10 19:16 ` Andi Kleen
2010-10-10 19:31 ` Milan Broz
2010-10-10 20:20 ` Andi Kleen
2010-10-11 9:32 ` Milan Broz
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