From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758220Ab2CSIHV (ORCPT ); Mon, 19 Mar 2012 04:07:21 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:39057 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752731Ab2CSIHR (ORCPT ); Mon, 19 Mar 2012 04:07:17 -0400 X-IronPort-AV: E=Sophos;i="4.73,611,1325433600"; d="scan'208";a="4567342" From: Lai Jiangshan To: "Paul E. McKenney" Cc: Lai Jiangshan , linux-kernel@vger.kernel.org, mingo@elte.hu, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, patches@linaro.org Subject: [PATCH 2/4 V2] rcu: use "int trycount" instead of "bool expedited" Date: Mon, 19 Mar 2012 16:12:12 +0800 Message-Id: <1332144734-9375-3-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1332144734-9375-1-git-send-email-laijs@cn.fujitsu.com> References: <1332144734-9375-1-git-send-email-laijs@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-03-19 16:05:04, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-03-19 16:05:07, Serialize complete at 2012-03-19 16:05:07 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the value of trycount for the strategy for expedited or not in srcu. Signed-off-by: Lai Jiangshan --- kernel/srcu.c | 27 ++++++++++++++------------- 1 files changed, 14 insertions(+), 13 deletions(-) diff --git a/kernel/srcu.c b/kernel/srcu.c index 9e86ed7..2923541 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -251,16 +251,16 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock); * we repeatedly block for 1-millisecond time periods. This approach * has done well in testing, so there is no need for a config parameter. */ -#define SYNCHRONIZE_SRCU_READER_DELAY 5 +#define SYNCHRONIZE_SRCU_READER_DELAY 5 +#define SYNCHRONIZE_SRCU_TRYCOUNT 2 +#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 12 /* * Wait until all the readers(which starts before this wait_idx() * with the specified idx) complete. */ -static void wait_idx(struct srcu_struct *sp, int idx, bool expedited) +static void wait_idx(struct srcu_struct *sp, int idx, int trycount) { - int trycount = 0; - /* * SRCU read-side critical sections are normally short, so wait * a small amount of time before possibly blocking. @@ -268,9 +268,10 @@ static void wait_idx(struct srcu_struct *sp, int idx, bool expedited) if (!srcu_readers_active_idx_check(sp, idx)) { udelay(SYNCHRONIZE_SRCU_READER_DELAY); while (!srcu_readers_active_idx_check(sp, idx)) { - if (expedited && ++ trycount < 10) + if (trycount > 0) { + trycount--; udelay(SYNCHRONIZE_SRCU_READER_DELAY); - else + } else schedule_timeout_interruptible(1); } } @@ -284,7 +285,7 @@ static void srcu_flip(struct srcu_struct *sp) /* * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). */ -static void __synchronize_srcu(struct srcu_struct *sp, bool expedited) +static void __synchronize_srcu(struct srcu_struct *sp, int trycount) { int busy_idx; @@ -301,8 +302,8 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited) * There are some readers start with idx=0, and some others start * with idx=1. So two wait_idx()s are enough for synchronize: * __synchronize_srcu() { - * wait_idx(sp, 0, expedited); - * wait_idx(sp, 1, expedited); + * wait_idx(sp, 0, trycount); + * wait_idx(sp, 1, trycount); * } * When it returns, all started readers have complete. * @@ -331,7 +332,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited) * Because this probability is not high, wait_idx() * will normally not need to wait. */ - wait_idx(sp, 1 - busy_idx, expedited); + wait_idx(sp, 1 - busy_idx, trycount); /* flip the index to ensure the return of the next wait_idx() */ srcu_flip(sp); @@ -339,7 +340,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited) /* * Now that wait_idx() has waited for the really old readers. */ - wait_idx(sp, busy_idx, expedited); + wait_idx(sp, busy_idx, trycount); mutex_unlock(&sp->mutex); } @@ -360,7 +361,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited) */ void synchronize_srcu(struct srcu_struct *sp) { - __synchronize_srcu(sp, 0); + __synchronize_srcu(sp, SYNCHRONIZE_SRCU_TRYCOUNT); } EXPORT_SYMBOL_GPL(synchronize_srcu); @@ -381,7 +382,7 @@ EXPORT_SYMBOL_GPL(synchronize_srcu); */ void synchronize_srcu_expedited(struct srcu_struct *sp) { - __synchronize_srcu(sp, 1); + __synchronize_srcu(sp, SYNCHRONIZE_SRCU_EXP_TRYCOUNT); } EXPORT_SYMBOL_GPL(synchronize_srcu_expedited); -- 1.7.4.4