Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752716AbZK0FtS (ORCPT ); Fri, 27 Nov 2009 00:49:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751462AbZK0FtR (ORCPT ); Fri, 27 Nov 2009 00:49:17 -0500 Received: from hera.kernel.org ([140.211.167.34]:57836 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751386AbZK0FtQ (ORCPT ); Fri, 27 Nov 2009 00:49:16 -0500 Date: Fri, 27 Nov 2009 05:48:47 GMT From: tip-bot for Anton Blanchard Cc: linux-kernel@vger.kernel.org, anton@samba.org, hpa@zytor.com, mingo@redhat.com, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, anton@samba.org, linux-kernel@vger.kernel.org, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20091127022820.GU32182@kryten> References: <20091127022820.GU32182@kryten> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/softlockup] softlockup: Fix hung_task_check_count sysctl Message-ID: Git-Commit-ID: e5af02261668350b43eb7381648930bde8e872f7 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1598 Lines: 45 Commit-ID: e5af02261668350b43eb7381648930bde8e872f7 Gitweb: http://git.kernel.org/tip/e5af02261668350b43eb7381648930bde8e872f7 Author: Anton Blanchard AuthorDate: Fri, 27 Nov 2009 13:28:20 +1100 Committer: Ingo Molnar CommitDate: Fri, 27 Nov 2009 06:21:57 +0100 softlockup: Fix hung_task_check_count sysctl I'm seeing spikes of up to 0.5ms in khungtaskd on a large machine. To reduce this source of jitter I tried setting hung_task_check_count to 0: # echo 0 > /proc/sys/kernel/hung_task_check_count which didn't have the intended response. Change to a post increment of max_count, so a value of 0 means check 0 tasks. Signed-off-by: Anton Blanchard Acked-by: Frederic Weisbecker Cc: msb@google.com LKML-Reference: <20091127022820.GU32182@kryten> Signed-off-by: Ingo Molnar --- kernel/hung_task.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index d4e8417..0c642d5 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -144,7 +144,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) rcu_read_lock(); do_each_thread(g, t) { - if (!--max_count) + if (!max_count--) goto unlock; if (!--batch_count) { batch_count = HUNG_TASK_BATCHING; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/