From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Andrea Arcangeli <aarcange@redhat.com>,
Avi Kivity <avi@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@elte.hu>,
akpm@linux-foundation.org,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
David Miller <davem@davemloft.net>,
Hugh Dickins <hugh.dickins@tiscali.co.uk>,
Mel Gorman <mel@csn.ul.ie>, Nick Piggin <npiggin@kernel.dk>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Yanmin Zhang <yanmin_zhang@linux.intel.com>,
Stephen Rothwell <sfr@canb.auug.org.au>
Subject: [PATCH 18/21] mutex: Provide mutex_is_contended
Date: Fri, 26 Nov 2010 15:39:01 +0100 [thread overview]
Message-ID: <20101126145411.270875001@chello.nl> (raw)
In-Reply-To: 20101126143843.801484792@chello.nl
[-- Attachment #1: mutex-is-contended.patch --]
[-- Type: text/plain, Size: 677 bytes --]
Usable for lock-breaks and such.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/mutex.h | 5 +++++
1 file changed, 5 insertions(+)
Index: linux-2.6/include/linux/mutex.h
===================================================================
--- linux-2.6.orig/include/linux/mutex.h
+++ linux-2.6/include/linux/mutex.h
@@ -118,6 +118,11 @@ static inline int mutex_is_locked(struct
return atomic_read(&lock->count) != 1;
}
+static inline int mutex_is_contended(struct mutex *lock)
+{
+ return atomic_read(&lock->count) < 0;
+}
+
/*
* See kernel/mutex.c for detailed documentation of these APIs.
* Also see Documentation/mutex-design.txt.
next prev parent reply other threads:[~2010-11-26 15:01 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-26 14:38 [PATCH 00/21] mm: Preemptibility -v6 Peter Zijlstra
2010-11-26 14:38 ` [PATCH 01/21] mm: Revert page_lock_anon_vma() lock annotation Peter Zijlstra
2010-11-30 1:19 ` KOSAKI Motohiro
2010-11-26 14:38 ` [PATCH 02/21] powerpc: Use call_rcu_sched() for pagetables Peter Zijlstra
2010-11-27 10:33 ` Nick Piggin
2010-11-27 21:55 ` Benjamin Herrenschmidt
2010-11-26 14:38 ` [PATCH 03/21] mm: Improve page_lock_anon_vma() comment Peter Zijlstra
2010-11-29 2:14 ` KAMEZAWA Hiroyuki
2010-11-26 14:38 ` [PATCH 04/21] mm: Rename drop_anon_vma to put_anon_vma Peter Zijlstra
2010-11-29 2:16 ` KAMEZAWA Hiroyuki
2010-11-26 14:38 ` [PATCH 05/21] mm: Move anon_vma ref out from under CONFIG_KSM Peter Zijlstra
2010-11-29 2:19 ` KAMEZAWA Hiroyuki
2010-11-26 14:38 ` [PATCH 06/21] mm: Simplify anon_vma refcounts Peter Zijlstra
2010-11-29 2:30 ` KAMEZAWA Hiroyuki
2010-11-26 14:38 ` [PATCH 07/21] mm: Use refcounts for page_lock_anon_vma() Peter Zijlstra
2010-11-29 2:35 ` KAMEZAWA Hiroyuki
2010-11-29 20:41 ` Peter Zijlstra
2010-11-30 1:21 ` KOSAKI Motohiro
2010-11-26 14:38 ` [PATCH 08/21] mm: Preemptible mmu_gather Peter Zijlstra
2010-11-29 2:53 ` KAMEZAWA Hiroyuki
2010-11-29 20:47 ` Peter Zijlstra
2010-11-26 14:38 ` [PATCH 09/21] powerpc: " Peter Zijlstra
2010-11-30 3:12 ` Benjamin Herrenschmidt
2010-11-30 3:35 ` Benjamin Herrenschmidt
2010-11-30 19:25 ` Peter Zijlstra
2010-11-26 14:38 ` [PATCH 10/21] sparc: " Peter Zijlstra
2010-11-26 14:38 ` [PATCH 11/21] s390: preemptible mmu_gather Peter Zijlstra
2010-11-26 14:38 ` [PATCH 12/21] arm: Preemptible mmu_gather Peter Zijlstra
2010-11-26 14:38 ` [PATCH 13/21] sh: " Peter Zijlstra
2010-11-26 14:38 ` [PATCH 14/21] um: " Peter Zijlstra
2010-11-26 14:38 ` [PATCH 15/21] ia64: " Peter Zijlstra
2010-11-26 14:38 ` [PATCH 16/21] mm, powerpc: Move the RCU page-table freeing into generic code Peter Zijlstra
2010-11-30 3:05 ` Benjamin Herrenschmidt
2010-11-26 14:39 ` [PATCH 17/21] lockdep, mutex: Provide mutex_lock_nest_lock Peter Zijlstra
2010-11-26 14:39 ` Peter Zijlstra [this message]
2010-11-29 2:58 ` [PATCH 18/21] mutex: Provide mutex_is_contended KAMEZAWA Hiroyuki
2010-11-29 20:49 ` Peter Zijlstra
2010-11-26 14:39 ` [PATCH 19/21] mm: Convert i_mmap_lock and anon_vma->lock to mutexes Peter Zijlstra
2010-11-29 3:05 ` KAMEZAWA Hiroyuki
2010-11-29 20:50 ` Peter Zijlstra
2010-11-30 1:28 ` KOSAKI Motohiro
2010-11-26 14:39 ` [PATCH 20/21] mm: Extended batches for generic mmu_gather Peter Zijlstra
2010-11-29 3:11 ` KAMEZAWA Hiroyuki
2010-11-26 14:39 ` [PATCH 21/21] mm: Optimize page_lock_anon_vma() fast-path Peter Zijlstra
2010-11-29 3:22 ` KAMEZAWA Hiroyuki
2010-11-29 9:00 ` [PATCH 00/21] mm: Preemptibility -v6 Benjamin Herrenschmidt
2010-11-29 11:41 ` Peter Zijlstra
2011-01-18 7:12 ` Hugh Dickins
2011-01-18 10:30 ` Peter Zijlstra
2011-01-18 10:44 ` Peter Zijlstra
2011-01-18 10:50 ` Peter Zijlstra
2011-01-19 17:10 ` Peter Zijlstra
2011-01-20 19:57 ` Hugh Dickins
2011-01-21 7:36 ` Benjamin Herrenschmidt
2011-01-21 15:33 ` Peter Zijlstra
2011-01-22 21:06 ` Paul E. McKenney
2011-01-23 11:03 ` Peter Zijlstra
2011-01-24 12:21 ` Peter Zijlstra
2011-01-24 14:34 ` Oleg Nesterov
2011-01-24 15:00 ` Peter Zijlstra
2011-01-24 15:33 ` Oleg Nesterov
2011-01-24 12:45 ` Peter Zijlstra
2011-01-24 14:24 ` Peter Zijlstra
2011-01-21 17:44 ` Andrea Arcangeli
2011-01-31 10:02 ` Martin Schwidefsky
2011-02-15 14:00 ` Martin Schwidefsky
2011-02-15 15:39 ` Martin Schwidefsky
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