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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2015-03-25 15:40:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-03-25 15:40:21 -0700 |
| commit | b8517e98305e3c76fa293133826afe39a690edcd (patch) | |
| tree | 55ce7797d169cd4f015b02a19c8762a72152951e /mm | |
| parent | Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux (diff) | |
| parent | writeback: fix possible underflow in write bandwidth calculation (diff) | |
| download | linux-dev-b8517e98305e3c76fa293133826afe39a690edcd.tar.xz linux-dev-b8517e98305e3c76fa293133826afe39a690edcd.zip | |
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
"A small collection of fixes that has been gathered over the last few
weeks. This contains:
- A one-liner fix for NVMe, fixing a missing list_head init that
could makes us oops on hitting recovery at load time.
- Two small blk-mq fixes:
- Fixup a bad goto jump on error handling.
- Fix for oopsing if running out of reserved tags.
- A memory leak fix for NBD.
- Two small writeback fixes from Tejun, fixing a missing init to
INITIAL_JIFFIES, and a possible underflow introduced recently.
- A core merge fixup in sg gap detection, where rq->biotail was
indexed with the count of rq->bio"
* 'for-linus' of git://git.kernel.dk/linux-block:
writeback: fix possible underflow in write bandwidth calculation
NVMe: Initialize device list head before starting
Fix bug in blk_rq_merge_ok
blkmq: Fix NULL pointer deref when all reserved tags in
blk-mq: fix use of incorrect goto label in blk_mq_init_queue error path
nbd: fix possible memory leak
writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth()
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page-writeback.c | 7 |
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 |