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	<20141020222841.419869904@infradead.org>
Date: Mon, 20 Oct 2014 16:41:45 -0700
Message-ID: <CA+55aFwd04q+O5ejbmDL-H7_GB6DEBMiiHkn+2R1u4uWxfDO9w@mail.gmail.com>
Subject: Re: [RFC][PATCH 4/6] SRCU free VMAs
From: Linus Torvalds <torvalds@linux-foundation.org>
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To: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>, Thomas Gleixner <tglx@linutronix.de>, Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>, Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@redhat.com>, Minchan Kim <minchan@kernel.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Al Viro <viro@zeniv.linux.org.uk>, Lai Jiangshan <laijs@cn.fujitsu.com>, Davidlohr Bueso <dave@stgolabs.net>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>

On Mon, Oct 20, 2014 at 2:56 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> Manage the VMAs with SRCU such that we can do a lockless VMA lookup.

Can you explain why srcu, and not plain regular rcu?

Especially as you then *note* some of the problems srcu can have.
Making it regular rcu would also seem to make it possible to make the
seqlock be just a seqcount, no?

                  Linus

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