Re: [PATCH v8 0/8] Reduce cross CPU IPI interference

From: "Michal Nazarewicz" <mina86@mina86.com>
To: linux-kernel@vger.kernel.org, "Gilad Ben-Yossef" <gilad@benyossef.com>
Cc: "Christoph Lameter" <cl@linux.com>,
	"Chris Metcalf" <cmetcalf@tilera.com>,
	"Frederic Weisbecker" <fweisbec@gmail.com>,
	linux-mm@kvack.org, "Pekka Enberg" <penberg@kernel.org>,
	"Matt Mackall" <mpm@selenic.com>,
	"Sasha Levin" <levinsasha928@gmail.com>,
	"Rik van Riel" <riel@redhat.com>,
	"Andi Kleen" <andi@firstfloor.org>, "Mel Gorman" <mel@csn.ul.ie>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Avi Kivity" <avi@redhat.com>,
	"Kosaki Motohiro" <kosaki.motohiro@gmail.com>,
	"Milton Miller" <miltonm@bga.com>
Subject: Re: [PATCH v8 0/8] Reduce cross CPU IPI interference
Date: Wed, 08 Feb 2012 10:36:42 +0100	[thread overview]
Message-ID: <op.v9cszgo23l0zgt@mpn-glaptop> (raw)
In-Reply-To: <1328448800-15794-1-git-send-email-gilad@benyossef.com>

On Sun, 05 Feb 2012 14:33:20 +0100, Gilad Ben-Yossef <gilad@benyossef.com> wrote:
> This patch set, inspired by discussions with Peter Zijlstra and Frederic
> Weisbecker when testing the nohz task patch set, is a first stab at trying
> to explore doing this by locating the places where such global IPI calls
> are being made and turning the global IPI into an IPI for a specific group
> of CPUs.  The purpose of the patch set is to get feedback if this is the
> right way to go for dealing with this issue and indeed, if the issue is
> even worth dealing with at all. Based on the feedback from this patch set
> I plan to offer further patches that address similar issue in other code
> paths.
>
> The patch creates an on_each_cpu_mask and on_each_cpu_cond infrastructure
> API (the former derived from existing arch specific versions in Tile and
> Arm) and uses them to turn several global IPI invocation to per CPU
> group invocations.

> Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> CC: Christoph Lameter <cl@linux.com>
> CC: Chris Metcalf <cmetcalf@tilera.com>
> CC: Frederic Weisbecker <fweisbec@gmail.com>
> CC: linux-mm@kvack.org
> CC: Pekka Enberg <penberg@kernel.org>
> CC: Matt Mackall <mpm@selenic.com>
> CC: Sasha Levin <levinsasha928@gmail.com>
> CC: Rik van Riel <riel@redhat.com>
> CC: Andi Kleen <andi@firstfloor.org>
> CC: Mel Gorman <mel@csn.ul.ie>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Alexander Viro <viro@zeniv.linux.org.uk>
> CC: Avi Kivity <avi@redhat.com>
> CC: Michal Nazarewicz <mina86@mina86.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

for patches form 1 to 4 and 7.  The other two (5 and 6) look good but
I don't know enough about slub and fs to feel confident acking.

> CC: Kosaki Motohiro <kosaki.motohiro@gmail.com>
> CC: Milton Miller <miltonm@bga.com>

-- 
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.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
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