From 18f1df4e00cea2eae41f3e5515b94d1e7127b2b6 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Mon, 8 Feb 2016 14:59:07 +1100 Subject: [PATCH] xfs: Make xfsaild freezeable again Hendik has reported suspend failures due to xfsaild blocking the freezer to settle down. Jan 17 19:59:56 linux-6380 kernel: PM: Syncing filesystems ... done. Jan 17 19:59:56 linux-6380 kernel: PM: Preparing system for sleep (mem) Jan 17 19:59:56 linux-6380 kernel: Freezing user space processes ... (elapsed 0.001 seconds) done. Jan 17 19:59:56 linux-6380 kernel: Freezing remaining freezable tasks ... Jan 17 19:59:56 linux-6380 kernel: Freezing of tasks failed after 20.002 seconds (1 tasks refusing to freeze, wq_busy=0): Jan 17 19:59:56 linux-6380 kernel: xfsaild/dm-5 S 00000000 0 1293 2 0x00000080 Jan 17 19:59:56 linux-6380 kernel: f0ef5f00 00000046 00000200 00000000 ffff9022 c02d3800 00000000 00000032 Jan 17 19:59:56 linux-6380 kernel: ee0b2400 00000032 f71e0d00 f36fabc0 f0ef2d00 f0ef6000 f0ef2d00 f12f90c0 Jan 17 19:59:56 linux-6380 kernel: f0ef5f0c c0844e44 00000000 f0ef5f6c f811e0be 00000000 00000000 f0ef2d00 Jan 17 19:59:56 linux-6380 kernel: Call Trace: Jan 17 19:59:56 linux-6380 kernel: [] schedule+0x34/0x90 Jan 17 19:59:56 linux-6380 kernel: [] xfsaild+0x5de/0x600 [xfs] Jan 17 19:59:56 linux-6380 kernel: [] kthread+0x9b/0xb0 Jan 17 19:59:56 linux-6380 kernel: [] ret_from_kernel_thread+0x21/0x38 The issue has been there for quite some time but it has been made visible by only by 24ba16bb3d49 ("xfs: clear PF_NOFREEZE for xfsaild kthread") because the suspend started seeing xfsaild. The above commit has missed that the !xfs_ail_min branch might call schedule with TASK_INTERRUPTIBLE without calling try_to_freeze so the pm suspend would wake up the kernel thread over and over again without any progress. What we want here is to use freezable_schedule instead to hide the thread from the suspend. While we are here also change schedule_timeout to freezable variant to prevent from spurious wakeups by suspend. [dchinner: re-add set_freezeable call so the freezer will account properly for this kthread. ] Reported-by: Hendrik Woltersdorf Signed-off-by: Michal Hocko Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_trans_ail.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 4f18fd92ca13..d6c9c3e9e02b 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -497,6 +497,7 @@ xfsaild( long tout = 0; /* milliseconds */ current->flags |= PF_MEMALLOC; + set_freezable(); while (!kthread_should_stop()) { if (tout && tout <= 20) @@ -519,14 +520,14 @@ xfsaild( if (!xfs_ail_min(ailp) && ailp->xa_target == ailp->xa_target_prev) { spin_unlock(&ailp->xa_lock); - schedule(); + freezable_schedule(); tout = 0; continue; } spin_unlock(&ailp->xa_lock); if (tout) - schedule_timeout(msecs_to_jiffies(tout)); + freezable_schedule_timeout(msecs_to_jiffies(tout)); __set_current_state(TASK_RUNNING); -- 2.20.1