From bde43c6c9f4f360ae549a0ed9f10a3e62e363aca Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Tue, 8 Sep 2015 15:04:05 -0700 Subject: mm/khugepaged: allow interruption of allocation sleep again Commit 1dfb059b9438 ("thp: reduce khugepaged freezing latency") fixed khugepaged to do not block a system suspend. But the result is that it could not get interrupted before the given timeout because the condition for the wait event is "false". This patch puts back the original approach but it uses freezable_schedule_timeout_interruptible() instead of schedule_timeout_interruptible(). It does the right thing. I am pretty sure that the freezable variant was not used in the original fix only because it was not available at that time. The regression has been there for ages. It was not critical. It just did the allocation throttling a little bit more aggressively. I found this problem when converting the kthread to kthread worker API and trying to understand the code. This bug is thought to have minimal userspace-visible impact. Somebody could set a high alloc_sleep value by mistake, and then try to fix it back, but khugepaged would keep sleeping until the high value expires. Signed-off-by: Petr Mladek Cc: Andrea Arcangeli Acked-by: Vlastimil Babka Cc: "Aneesh Kumar K.V" Cc: "Kirill A. Shutemov" Cc: David Rientjes Cc: Ebru Akagunduz Cc: Mel Gorman Cc: Jiri Kosina Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 883f613ada7e..b16279cbd91d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2326,8 +2326,12 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page, static void khugepaged_alloc_sleep(void) { - wait_event_freezable_timeout(khugepaged_wait, false, - msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); + DEFINE_WAIT(wait); + + add_wait_queue(&khugepaged_wait, &wait); + freezable_schedule_timeout_interruptible( + msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); + remove_wait_queue(&khugepaged_wait, &wait); } static int khugepaged_node_load[MAX_NUMNODES]; -- cgit v1.2.3