The patch titled
freezer: fix racy usage of try_to_freeze in kswapd
has been added to the -mm tree. Its filename is
freezer-fix-racy-usage-of-try_to_freeze-in-kswapd.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: freezer: fix racy usage of try_to_freeze in kswapd
From: Rafael J. Wysocki <rjw@xxxxxxx>
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@xxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 13 +++++++++----
1 files changed, 9 insertions(+), 4 deletions(-)
diff -puN mm/vmscan.c~freezer-fix-racy-usage-of-try_to_freeze-in-kswapd mm/vmscan.c
--- a/mm/vmscan.c~freezer-fix-racy-usage-of-try_to_freeze-in-kswapd
+++ a/mm/vmscan.c
@@ -1393,8 +1393,6 @@ 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;
@@ -1405,12 +1403,19 @@ 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;
}
_
Patches currently in -mm which might be from rjw@xxxxxxx are
pktgen-add-try_to_freeze.patch
fix-refrigerator-vs-thaw_process-race.patch
swsusp-use-inline-functions-for-changing-page-flags.patch
swsusp-do-not-use-page-flags.patch
mm-remove-unused-page-flags.patch
swsusp-fix-error-paths-in-snapshot_open.patch
swsusp-use-gfp_kernel-for-creating-basic-data-structures.patch
rework-pm_ops-pm_disk_mode-kill-misuse.patch
power-management-remove-firmware-disk-mode.patch
power-management-implement-pm_opsvalid-for-everybody.patch
power-management-force-pm_opsvalid-callback-to-be.patch
freezer-remove-pf_nofreeze-from-handle_initrd.patch
swsusp-use-rbtree-for-tracking-allocated-swap.patch
freezer-fix-racy-usage-of-try_to_freeze-in-kswapd.patch
freezer-task-exit_state-should-be-treated-as-bolean.patch
documentation-ask-driver-writers-to-provide-pm-support.patch
freezer-read-pf_borrowed_mm-in-a-nonracy-way.patch
freezer-close-theoretical-race-between-refrigerator-and-thaw_tasks.patch
freezer-remove-pf_nofreeze-from-rcutorture-thread.patch
freezer-remove-pf_nofreeze-from-bluetooth-threads.patch
freezer-add-try_to_freeze-calls-to-all-kernel-threads.patch
freezer-fix-vfork-problem.patch
freezer-take-kernel_execve-into-consideration.patch
shrink_slab-handle-bad-shrinkers.patch
-
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