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| author | Rafael J. Wysocki <rjw@sisk.pl> | 2007-05-06 14:50:48 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 12:12:59 -0700 |
| commit | b1296cc48b39355241470ef934a5e2270e3f23bd (patch) | |
| tree | cfaf24de442b9ce19414f67106461f7c4829a1a7 | |
| parent | d1d241cc2c5feec057c370aa71637380b1b945d5 (diff) | |
| download | op-kernel-dev-b1296cc48b39355241470ef934a5e2270e3f23bd.zip op-kernel-dev-b1296cc48b39355241470ef934a5e2270e3f23bd.tar.gz | |
freezer: fix racy usage of try_to_freeze in kswapd
Currently we can miss freeze_process()->signal_wake_up() in kswapd() if it
happens between try_to_freeze() and prepare_to_wait(). To prevent this
from happening we should check freezing(current) before calling schedule().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/vmscan.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index db023e2..56651a1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1323,8 +1323,6 @@ static int kswapd(void *p) for ( ; ; ) { unsigned long new_order; - try_to_freeze(); - prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE); new_order = pgdat->kswapd_max_order; pgdat->kswapd_max_order = 0; @@ -1335,12 +1333,19 @@ static int kswapd(void *p) */ order = new_order; } else { - schedule(); + if (!freezing(current)) + schedule(); + order = pgdat->kswapd_max_order; } finish_wait(&pgdat->kswapd_wait, &wait); - balance_pgdat(pgdat, order); + if (!try_to_freeze()) { + /* We can speed up thawing tasks if we don't call + * balance_pgdat after returning from the refrigerator + */ + balance_pgdat(pgdat, order); + } } return 0; } |
