block: Prevent hang_check firing during long I/O (4b197769) · Commits · 戴 / test

During long I/O operations, the hang_check timer may fire, trigger stack dumps that unnecessarily alarm the user. Eg. hdparm --security-erase NULL /dev/sdb ## can take *hours* to complete So, if hang_check is armed, we should wake up periodically to prevent it from triggering. This patch uses a wake-up interval equal to half the hang_check timer period, which keeps overhead low enough. Signed-off-by:

Mark Lord <mlord@pobox.com> Signed-off-by:

Jens Axboe <jaxboe@fusionio.com>

block/blk-exec.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -80,6 +80,7 @@ int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,
		DECLARE_COMPLETION_ONSTACK(wait);
		char sense[SCSI_SENSE_BUFFERSIZE];
		int err = 0;
		unsigned long hang_check;

		/*
		* we need an extra reference to the request, so we can look at
		@@ -95,6 +96,12 @@ int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,

		rq->end_io_data = &wait;
		blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);

		/* Prevent hang_check timer from firing at us during very long I/O */
		hang_check = sysctl_hung_task_timeout_secs;
		if (hang_check)
		while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2)));
		else
		wait_for_completion(&wait);

		if (rq->errors)

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