Hi Mel, On 04/30/2013 12:31 AM, Mel Gorman wrote:
Andrew Perepechko reported a problem whereby pages are being prematurely evicted as the mark_page_accessed() hint is ignored for pages that are currently on a pagevec -- http://www.spinics.net/lists/linux-ext4/msg37340.html . Alexey Lyahkov and Robin Dong have also reported problems recently that could be due to hot pages reaching the end of the inactive list too quickly and be reclaimed.
Both shrink_active_list and shrink_inactive_list can call lru_add_drain(), why the hot pages can't be mark Actived during this time?
Rather than addressing this on a per-filesystem basis, this series aims to fix the mark_page_accessed() interface by deferring what LRU a page is added to pagevec drain time and allowing mark_page_accessed() to call SetPageActive on a pagevec page. This opens some important races that I think should be harmless but needs double checking. The races and the VM_BUG_ON checks that are removed are all described in patch 2. This series received only very light testing but it did not immediately blow up and a debugging patch confirmed that pages are now getting added to the active file LRU list that would previously have been added to the inactive list. fs/cachefiles/rdwr.c | 30 ++++++------------------ fs/nfs/dir.c | 7 ++---- include/linux/pagevec.h | 34 +-------------------------- mm/swap.c | 61 ++++++++++++++++++++++++------------------------- mm/vmscan.c | 3 --- 5 files changed, 40 insertions(+), 95 deletions(-)
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