linux-kernel - Re: [PATCH] vfs: Avoid IPI storm due to bh LRU invalidation

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Message-ID: <CAOtvUMet_L9s5+jYF=_kb_N86dNmC6G1rhLQ7JzNfWC0J9UcSw@mail.gmail.com>
Date:	Wed, 8 Feb 2012 09:09:30 +0200
From:	Gilad Ben-Yossef <gilad@...yossef.com>
To:	Jan Kara <jack@...e.cz>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	linux-fsdevel@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	hare@...e.de, Al Viro <viro@...iv.linux.org.uk>,
	Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH] vfs: Avoid IPI storm due to bh LRU invalidation

On Tue, Feb 7, 2012 at 8:29 PM, Jan Kara <jack@...e.cz> wrote:
> On Tue 07-02-12 18:25:18, Gilad Ben-Yossef wrote:
>> On Tue, Feb 7, 2012 at 12:25 AM, Jan Kara <jack@...e.cz> wrote:
...
>> I think its worth a shot since the mutex just delays the IPIs instead
>> of canceling them
>> altogether.
>  Well, mutex will just delay callers but the sequence logic behind the
> mutex will reduce number of IPIs a lot - all waiters for mutex will be
> satisfied by a single signalling of all CPUs while previously they would
> each do the signalling.

Oh, you are right. I've missed that part completely. Note to self: never try to
read LKML email on your smartphone...

Gilad


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Gilad Ben-Yossef
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