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Commit 1dfb059b authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds
Browse files

thp: reduce khugepaged freezing latency 



khugepaged can sometimes cause suspend to fail, requiring that the user
retry the suspend operation.

Use wait_event_freezable_timeout() instead of
schedule_timeout_interruptible() to avoid missing freezer wakeups.  A
try_to_freeze() would have been needed in the khugepaged_alloc_hugepage
tight loop too in case of the allocation failing repeatedly, and
wait_event_freezable_timeout will provide it too.

khugepaged would still freeze just fine by trying again the next minute
but it's better if it freezes immediately.

Reported-by: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Tested-by: default avatarJiri Slaby <jslaby@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b53fc7c2

mm/huge_memory.c

+4 −12
Original line number Diff line number Diff line
@@ -2259,12 +2259,8 @@ static void khugepaged_do_scan(struct page **hpage) 


static void khugepaged_alloc_sleep(void)

{

	DEFINE_WAIT(wait);

	add_wait_queue(&khugepaged_wait, &wait);

	schedule_timeout_interruptible(

		msecs_to_jiffies(

			khugepaged_alloc_sleep_millisecs));

	remove_wait_queue(&khugepaged_wait, &wait);

	wait_event_freezable_timeout(khugepaged_wait, false,

			msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));

}



#ifndef CONFIG_NUMA
@@ -2313,14 +2309,10 @@ static void khugepaged_loop(void) 
		if (unlikely(kthread_should_stop()))

			break;

		if (khugepaged_has_work()) {

			DEFINE_WAIT(wait);

			if (!khugepaged_scan_sleep_millisecs)

				continue;

			add_wait_queue(&khugepaged_wait, &wait);

			schedule_timeout_interruptible(

				msecs_to_jiffies(

					khugepaged_scan_sleep_millisecs));

			remove_wait_queue(&khugepaged_wait, &wait);

			wait_event_freezable_timeout(khugepaged_wait, false,

			    msecs_to_jiffies(khugepaged_scan_sleep_millisecs));

		} else if (khugepaged_enabled())

			wait_event_freezable(khugepaged_wait,

					     khugepaged_wait_event());