Message-ID: <4BC09032.1060004@dcl.info.waseda.ac.jp>
Date: Sat, 10 Apr 2010 23:50:26 +0900
From: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
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To: Peter Zijlstra <peterz@infradead.org>
CC: mingo@elte.hu, linux-kernel@vger.kernel.org, h.mitake@gmail.com,
       Paul Mackerras <paulus@samba.org>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH] Add "nested" field to event of lock_release
References: <1270896100-7935-1-git-send-email-mitake@dcl.info.waseda.ac.jp> <1270907986.4222.2.camel@twins>
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On 04/10/10 22:59, Peter Zijlstra wrote:
 > On Sat, 2010-04-10 at 19:41 +0900, Hitoshi Mitake wrote:
 >> State machine of perf lock requires "nested" field of lock_release(),
 >> so this patch adds it to event.
 >>
 >> Signed-off-by: Hitoshi Mitake<mitake@dcl.info.waseda.ac.jp>
 >> Cc: Peter Zijlstra<a.p.zijlstra@chello.nl>
 >> Cc: Paul Mackerras<paulus@samba.org>
 >> Cc: Arnaldo Carvalho de Melo<acme@redhat.com>
 >> Cc: Frederic Weisbecker<fweisbec@gmail.com>
 >
 > The nested flag only indicates if it could be nested, not if it was
 > actually nested. So no, this doesn't make any sense at all.
 >
 > (in fact, pretty much every lock_release out there has nested=1)
 >

Ah, sorry, I misunderstood.
When looked at rwlock_release(), I judged that nested is required,
because double or more read_lock() is allowed.

Thanks for your correction :)
        Hitoshi
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