thp: do not adjust zone water marks if khugepaged is not started

set_recommended_min_free_kbytes() adjusts zone water marks to be suitable
for khugepaged. We avoid doing this if khugepaged is disabled, but don't
catch the case when khugepaged is failed to start.

Let's address this by checking khugepaged_thread instead of
khugepaged_enabled() in set_recommended_min_free_kbytes().
It's NULL if the kernel thread is stopped or failed to start.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c257006749bb90207f28df234c6d9736b945b18d..0af19fffe1dfcdc1875fe39156a335d7c8343bb7 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -110,7 +110,8 @@ static int set_recommended_min_free_kbytes(void)
        int nr_zones = 0;
        unsigned long recommended_min;
 
-       if (!khugepaged_enabled())
+       /* khugepaged thread has stopped to failed to start */
+       if (!khugepaged_thread)
                return 0;
 
        for_each_populated_zone(zone)