From: Pekka Enberg <penberg@cs.helsinki.fi>
To: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-kernel@vger.kernel.org,
Frederic Weisbecker <fweisbec@gmail.com>,
Russell King <linux@arm.linux.org.uk>,
Chris Metcalf <cmetcalf@tilera.com>,
linux-mm@kvack.org, Christoph Lameter <cl@linux-foundation.org>,
Matt Mackall <mpm@selenic.com>
Subject: Re: [PATCH 5/5] slub: Only IPI CPUs that have per cpu obj to flush
Date: Mon, 26 Sep 2011 13:03:19 +0300 (EEST) [thread overview]
Message-ID: <alpine.LFD.2.02.1109261300200.15514@tux.localdomain> (raw)
In-Reply-To: <CAOtvUMfnrtonwbCn4j=weA-kjf4K0SG2YRwZ-Cy5XONNWyN_pQ@mail.gmail.com>
On Mon, 26 Sep 2011, Gilad Ben-Yossef wrote:
> Peter basically already answered better then I could :-)
>
> All I have to add is an example -
>
> flush_all() is called for each kmem_cahce_destroy(). So every cache
> being destroyed dynamically ends up sending an IPI to each CPU in the
> system, regardless if the cache has ever been used there.
>
> For example, if you close the Infinband ipath driver char device file,
> the close file ops calls kmem_cache_destroy().So, if I understand
> correctly, running some infiniband config tool on one a single CPU
> dedicated to system tasks might interrupt the rest of the 127 CPUs I
> dedicated to some CPU intensive task. This is the scenario I'm
> tryingto avoid.
>
> I suspect there is a good chance that every line in the output of "git
> grep kmem_cache_destroy linux/ | grep '\->'" has a similar scenario
> (there are 42 of them).
>
> I hope this sheds some light on the motive of the work.
Sure.
If you write down such information in the changelog for future patches, I
don't need to waste your time asking for an explanation. ;-)
Pekka
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next prev parent reply other threads:[~2011-09-26 10:03 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-25 8:54 [PATCH 0/5] Reduce cross CPU IPI interference Gilad Ben-Yossef
2011-09-25 8:54 ` [PATCH 1/5] smp: Introduce a generic on_each_cpu_mask function Gilad Ben-Yossef
2011-09-25 11:37 ` Sasha Levin
2011-09-26 8:48 ` Peter Zijlstra
2011-09-25 8:54 ` [PATCH 2/5] arm: Move arm over to generic on_each_cpu_mask Gilad Ben-Yossef
2011-09-25 8:54 ` [PATCH 3/5] tile: Move tile to use " Gilad Ben-Yossef
2011-09-25 8:54 ` [PATCH 4/5] mm: Only IPI CPUs to drain local pages if they exist Gilad Ben-Yossef
2011-09-26 1:52 ` Shaohua Li
2011-09-26 6:47 ` Gilad Ben-Yossef
2011-09-26 15:24 ` Christoph Lameter
2011-09-27 7:27 ` Gilad Ben-Yossef
2011-09-27 16:13 ` Christoph Lameter
2011-09-26 7:28 ` Peter Zijlstra
2011-09-26 8:39 ` Gilad Ben-Yossef
2011-09-26 7:29 ` Peter Zijlstra
2011-09-25 8:54 ` [PATCH 5/5] slub: Only IPI CPUs that have per cpu obj to flush Gilad Ben-Yossef
2011-09-26 6:54 ` Pekka Enberg
2011-09-26 7:36 ` Peter Zijlstra
2011-09-26 8:07 ` Gilad Ben-Yossef
2011-09-26 10:03 ` Pekka Enberg [this message]
2011-09-26 8:10 ` Gilad Ben-Yossef
2011-09-26 7:33 ` Peter Zijlstra
2011-09-26 8:35 ` Gilad Ben-Yossef
2011-09-26 9:28 ` Pekka Enberg
2011-09-26 9:45 ` Peter Zijlstra
2011-09-26 12:05 ` Gilad Ben-Yossef
2011-09-26 13:49 ` Gilad Ben-Yossef
2011-09-26 7:20 ` [PATCH 0/5] Reduce cross CPU IPI interference Peter Zijlstra
2011-09-26 8:43 ` Gilad Ben-Yossef
2011-09-26 8:46 ` Peter Zijlstra
2011-09-28 13:00 ` Chris Metcalf
2011-10-02 8:44 ` Gilad Ben-Yossef
2011-10-02 14:58 ` Chris Metcalf
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