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authorThomas Gleixner <tglx@linutronix.de>2015-04-08 23:26:21 +0200
committerThomas Gleixner <tglx@linutronix.de>2015-04-08 23:26:21 +0200
commit462b69b1e43ceccab68a47d65b1e46520cd0fdc0 (patch)
tree3c961fcb5889c5ab14ab36d8ef7421fc96c95959 /mm/page-writeback.c
parentd8bf368d0631d4bc2612d8bf2e4e8e74e620d0cc (diff)
parentf22e6e847115abc3a0e2ad7bb18d243d42275af1 (diff)
Merge branch 'linus' into irq/core to get the GIC updates which
conflict with pending GIC changes. Conflicts: drivers/usb/isp1760/isp1760-core.c
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 45e187b2d971..644bcb665773 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -857,8 +857,11 @@ static void bdi_update_write_bandwidth(struct backing_dev_info *bdi,
* bw * elapsed + write_bandwidth * (period - elapsed)
* write_bandwidth = ---------------------------------------------------
* period
+ *
+ * @written may have decreased due to account_page_redirty().
+ * Avoid underflowing @bw calculation.
*/
- bw = written - bdi->written_stamp;
+ bw = written - min(written, bdi->written_stamp);
bw *= HZ;
if (unlikely(elapsed > period)) {
do_div(bw, elapsed);
@@ -922,7 +925,7 @@ static void global_update_bandwidth(unsigned long thresh,
unsigned long now)
{
static DEFINE_SPINLOCK(dirty_lock);
- static unsigned long update_time;
+ static unsigned long update_time = INITIAL_JIFFIES;
/*
* check locklessly first to optimize away locking for the most time