thp: freeze khugepaged and ksmd
It's unclear why schedule friendly kernel threads can't be taken away by
the CPU through the scheduler itself. It's safer to stop them as they can
trigger memory allocation, if kswapd also freezes itself to avoid
generating I/O they have too.
Signed-off-by: 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 39d7df4..45b6d53b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -15,6 +15,7 @@
#include <linux/mm_inline.h>
#include <linux/kthread.h>
#include <linux/khugepaged.h>
+#include <linux/freezer.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
#include "internal.h"
@@ -2085,6 +2086,9 @@
break;
#endif
+ if (unlikely(kthread_should_stop() || freezing(current)))
+ break;
+
spin_lock(&khugepaged_mm_lock);
if (!khugepaged_scan.mm_slot)
pass_through_head++;
@@ -2147,6 +2151,9 @@
if (hpage)
put_page(hpage);
#endif
+ try_to_freeze();
+ if (unlikely(kthread_should_stop()))
+ break;
if (khugepaged_has_work()) {
DEFINE_WAIT(wait);
if (!khugepaged_scan_sleep_millisecs)
@@ -2157,8 +2164,8 @@
khugepaged_scan_sleep_millisecs));
remove_wait_queue(&khugepaged_wait, &wait);
} else if (khugepaged_enabled())
- wait_event_interruptible(khugepaged_wait,
- khugepaged_wait_event());
+ wait_event_freezable(khugepaged_wait,
+ khugepaged_wait_event());
}
}
@@ -2166,6 +2173,7 @@
{
struct mm_slot *mm_slot;
+ set_freezable();
set_user_nice(current, 19);
/* serialize with start_khugepaged() */
@@ -2180,6 +2188,8 @@
mutex_lock(&khugepaged_mutex);
if (!khugepaged_enabled())
break;
+ if (unlikely(kthread_should_stop()))
+ break;
}
spin_lock(&khugepaged_mm_lock);