Messages in this thread Patch in this message | | | Date | Mon, 21 Nov 2011 21:03:45 +0800 | From | Wu Fengguang <> | Subject | [PATCH 3/5] writeback: fix dirtied pages accounting on sub-page writes |
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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 nr_dirtied at page dirty time.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> --- mm/page-writeback.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- linux-next.orig/mm/page-writeback.c 2011-11-17 20:57:13.000000000 +0800 +++ linux-next/mm/page-writeback.c 2011-11-17 20:57:15.000000000 +0800 @@ -1224,8 +1224,6 @@ void balance_dirty_pages_ratelimited_nr( 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 @@ -1734,6 +1732,7 @@ void account_page_dirtied(struct page *p __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++; } } EXPORT_SYMBOL(account_page_dirtied);
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