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| author | Wu Fengguang <fengguang.wu@intel.com> | 2011-04-14 07:52:37 -0600 |
|---|---|---|
| committer | Wu Fengguang <fengguang.wu@intel.com> | 2011-12-18 14:20:22 +0800 |
| commit | d3bc1fef9389e409a772ea174a5e41a6f93d9b7b (patch) | |
| tree | d1e47354263b7c930a7ec4428909693d10a10c50 | |
| parent | 54848d73f9f254631303d6eab9b976855988b266 (diff) | |
| download | linux-d3bc1fef9389e409a772ea174a5e41a6f93d9b7b.tar.gz linux-d3bc1fef9389e409a772ea174a5e41a6f93d9b7b.tar.bz2 linux-d3bc1fef9389e409a772ea174a5e41a6f93d9b7b.zip | |
writeback: fix dirtied pages accounting on sub-page writes
When dd in 512bytes, generic_perform_write() calls
balance_dirty_pages_ratelimited() 8 times for the same page, but
obviously the page is only dirtied once.
Fix it by accounting tsk->nr_dirtied and bdp_ratelimits at page dirty time.
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
| -rw-r--r-- | mm/page-writeback.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 619c445fc03c..5d1ef5d8613a 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1258,8 +1258,6 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, if (bdi->dirty_exceeded) ratelimit = min(ratelimit, 32 >> (PAGE_SHIFT - 10)); - current->nr_dirtied += nr_pages_dirtied; - preempt_disable(); /* * This prevents one CPU to accumulate too many dirtied pages without @@ -1270,12 +1268,9 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, p = &__get_cpu_var(bdp_ratelimits); if (unlikely(current->nr_dirtied >= ratelimit)) *p = 0; - else { - *p += nr_pages_dirtied; - if (unlikely(*p >= ratelimit_pages)) { - *p = 0; - ratelimit = 0; - } + else if (unlikely(*p >= ratelimit_pages)) { + *p = 0; + ratelimit = 0; } /* * Pick up the dirtied pages by the exited tasks. This avoids lots of @@ -1768,6 +1763,8 @@ void account_page_dirtied(struct page *page, struct address_space *mapping) __inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE); __inc_bdi_stat(mapping->backing_dev_info, BDI_DIRTIED); task_io_account_write(PAGE_CACHE_SIZE); + current->nr_dirtied++; + this_cpu_inc(bdp_ratelimits); } } EXPORT_SYMBOL(account_page_dirtied); |