Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753440Ab2FMAxM (ORCPT ); Tue, 12 Jun 2012 20:53:12 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:55258 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753002Ab2FMAxJ (ORCPT ); Tue, 12 Jun 2012 20:53:09 -0400 From: Wanpeng Li To: Fengguang Wu Cc: Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Gavin Shan , Wanpeng Li Subject: [PATCH] writeback: fix hung_task alarm when sync block Date: Wed, 13 Jun 2012 08:52:53 +0800 Message-Id: <1339548774-4834-1-git-send-email-liwp.linux@gmail.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3225 Lines: 81 From: Wanpeng Li I use several dd processes to write a slow SD card dd if=/dev/sda1 of=/dev/sdc4 bs=1M count=4000 and several sync commands(maybe > 10),dmesg show this: [ 366.888741] INFO: task sync:3518 blocked for more than 120 seconds. [ 366.888742] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 366.888746] sync D 00000201 0 3518 3462 0x00000000 [ 366.888752] dcde5e54 00000082 00000000 00000201 00000000 c180d220 c1933d00 c1933d00 [ 366.888758] 614a7ae7 00000023 f6bc0d00 ebecb280 c180d220 f6bc0d6c f04acbfc 00000000 [ 366.888786] f6bc0d6c dcde5e2c 00000023 f6bc0d44 00000000 00000000 ebd8b2b4 dcde5e6c [ 366.888788] Call Trace: [ 366.888792] [] ? enqueue_entity+0xee/0x5a0 [ 366.888795] [] schedule+0x23/0x60 [ 366.888798] [] schedule_timeout+0x22d/0x2a0 [ 366.888801] [] ? check_preempt_curr+0x72/0x90 [ 366.888804] [] ? ttwu_do_wakeup+0x28/0x130 [ 366.888807] [] ? default_spin_lock_flags+0x8/0x10 [ 366.888810] [] ? _raw_spin_lock_irqsave+0x2d/0x40 [ 366.888813] [] wait_for_common+0xa7/0x110 [ 366.888816] [] ? try_to_wake_up+0x220/0x220 [ 366.888819] [] wait_for_completion+0x17/0x20 [ 366.888822] [] writeback_inodes_sb_nr+0x70/0x90 [ 366.888825] [] writeback_inodes_sb+0x25/0x30 [ 366.888828] [] __sync_filesystem+0x4f/0x90 [ 366.888831] [] sync_one_sb+0x17/0x20 [ 366.888834] [] iterate_supers+0xc0/0xd0 [ 366.888837] [] ? __sync_filesystem+0x90/0x90 [ 366.888840] [] sys_sync+0x2b/0x60 [ 366.888842] [] sysenter_do_call+0x12/0x28 Too many similar messages flood the logs. So I use a present method to fix this issue. ------------------------------------------ Author: Mark Lord Date: Fri Sep 24 09:51:13 2010 -0400 block: Prevent hang_check firing during long I/O ------------------------------------------ Signed-off-by: Wanpeng Li --- fs/fs-writeback.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index f2d0109..5d403a1 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1300,6 +1300,7 @@ void writeback_inodes_sb_nr(struct super_block *sb, enum wb_reason reason) { DECLARE_COMPLETION_ONSTACK(done); + unsigned long hangcheck; struct wb_writeback_work work = { .sb = sb, .sync_mode = WB_SYNC_NONE, @@ -1311,7 +1312,12 @@ void writeback_inodes_sb_nr(struct super_block *sb, WARN_ON(!rwsem_is_locked(&sb->s_umount)); bdi_queue_work(sb->s_bdi, &work); - wait_for_completion(&done); + hangcheck = sysctl_hung_task_timeout_secs; + if (hangcheck) + while (!wait_for_completion_timeout(&done, HZ/2)) + ; + else + wait_for_completion(&done); } EXPORT_SYMBOL(writeback_inodes_sb_nr); -- 1.7.9.5 -- 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/