В Вт., 27/12/2011 в 11:15 +0900, KAMEZAWA Hiroyuki пишет: > On Sat, 24 Dec 2011 07:45:03 +1100 > Dave Chinner <david@xxxxxxxxxxxxx> wrote: > > > On Fri, Dec 23, 2011 at 03:04:02PM +0400, nowhere wrote: > > > В Пт., 23/12/2011 в 21:20 +1100, Dave Chinner пишет: > > > > On Fri, Dec 23, 2011 at 01:01:20PM +0400, nowhere wrote: > > > > > В Чт., 22/12/2011 в 09:55 +1100, Dave Chinner пишет: > > > > > > On Wed, Dec 21, 2011 at 10:52:49AM +0100, Michal Hocko wrote: > > > > Here is the report of trace-cmd while dd'ing > > > https://80.237.6.56/report-dd.xz > > > > Ok, it's not a shrink_slab() problem - it's just being called ~100uS > > by kswapd. The pattern is: > > > > - reclaim 94 (batches of 32,32,30) pages from iinactive list > > of zone 1, node 0, prio 12 > > - call shrink_slab > > - scan all caches > > - all shrinkers return 0 saying nothing to shrink > > - 40us gap > > - reclaim 10-30 pages from inactive list of zone 2, node 0, prio 12 > > - call shrink_slab > > - scan all caches > > - all shrinkers return 0 saying nothing to shrink > > - 40us gap > > - isolate 9 pages from LRU zone ?, node ?, none isolated, none freed > > - isolate 22 pages from LRU zone ?, node ?, none isolated, none freed > > - call shrink_slab > > - scan all caches > > - all shrinkers return 0 saying nothing to shrink > > 40us gap > > > > And it just repeats over and over again. After a while, nid=0,zone=1 > > drops out of the traces, so reclaim only comes in batches of 10-30 > > pages from zone 2 between each shrink_slab() call. > > > > The trace starts at 111209.881s, with 944776 pages on the LRUs. It > > finishes at 111216.1 with kswapd going to sleep on node 0 with > > 930067 pages on the LRU. So 7 seconds to free 15,000 pages (call it > > 2,000 pages/s) which is awfully slow.... > > > > vmscan gurus - time for you to step in now... > > > > Can you show /proc/zoneinfo ? I want to know each zone's size. $ cat /proc/zoneinfo Node 0, zone DMA pages free 3980 min 64 low 80 high 96 scanned 0 spanned 4080 present 3916 nr_free_pages 3980 nr_inactive_anon 0 nr_active_anon 0 nr_inactive_file 0 nr_active_file 0 nr_unevictable 0 nr_mlock 0 nr_anon_pages 0 nr_mapped 0 nr_file_pages 0 nr_dirty 0 nr_writeback 0 nr_slab_reclaimable 0 nr_slab_unreclaimable 0 nr_page_table_pages 0 nr_kernel_stack 0 nr_unstable 0 nr_bounce 0 nr_vmscan_write 0 nr_vmscan_immediate_reclaim 0 nr_writeback_temp 0 nr_isolated_anon 0 nr_isolated_file 0 nr_shmem 0 nr_dirtied 0 nr_written 0 nr_anon_transparent_hugepages 0 protection: (0, 3503, 4007, 4007) pagesets cpu: 0 count: 0 high: 0 batch: 1 vm stats threshold: 4 cpu: 1 count: 0 high: 0 batch: 1 vm stats threshold: 4 all_unreclaimable: 1 start_pfn: 16 inactive_ratio: 1 Node 0, zone DMA32 pages free 19620 min 14715 low 18393 high 22072 scanned 0 spanned 1044480 present 896960 nr_free_pages 19620 nr_inactive_anon 43203 nr_active_anon 206577 nr_inactive_file 412249 nr_active_file 126151 nr_unevictable 7 nr_mlock 7 nr_anon_pages 108557 nr_mapped 6683 nr_file_pages 540415 nr_dirty 5 nr_writeback 0 nr_slab_reclaimable 58887 nr_slab_unreclaimable 12145 nr_page_table_pages 1389 nr_kernel_stack 100 nr_unstable 0 nr_bounce 0 nr_vmscan_write 1021 nr_vmscan_immediate_reclaim 69337 nr_writeback_temp 0 nr_isolated_anon 0 nr_isolated_file 0 nr_shmem 1861 nr_dirtied 1586363 nr_written 1245872 nr_anon_transparent_hugepages 272 protection: (0, 0, 504, 504) pagesets cpu: 0 count: 4 high: 186 batch: 31 vm stats threshold: 24 cpu: 1 count: 0 high: 186 batch: 31 vm stats threshold: 24 all_unreclaimable: 0 start_pfn: 4096 inactive_ratio: 5 Node 0, zone Normal pages free 2854 min 2116 low 2645 high 3174 scanned 0 spanned 131072 present 129024 nr_free_pages 2854 nr_inactive_anon 20682 nr_active_anon 10262 nr_inactive_file 47083 nr_active_file 11292 nr_unevictable 518 nr_mlock 518 nr_anon_pages 22801 nr_mapped 1798 nr_file_pages 58853 nr_dirty 0 nr_writeback 0 nr_slab_reclaimable 4347 nr_slab_unreclaimable 5955 nr_page_table_pages 769 nr_kernel_stack 128 nr_unstable 0 nr_bounce 0 nr_vmscan_write 5285 nr_vmscan_immediate_reclaim 51475 nr_writeback_temp 0 nr_isolated_anon 0 nr_isolated_file 0 nr_shmem 28 nr_dirtied 251597 nr_written 191561 nr_anon_transparent_hugepages 16 protection: (0, 0, 0, 0) pagesets cpu: 0 count: 30 high: 186 batch: 31 vm stats threshold: 12 cpu: 1 count: 0 high: 186 batch: 31 vm stats threshold: 12 all_unreclaimable: 0 start_pfn: 1048576 inactive_ratio: > > Below is my memo. > > In trace log, priority = 11 or 12. Then, I think kswapd can reclaim memory > to satisfy "sc.nr_reclaimed >= SWAP_CLUSTER_MAX" condition and loops again. > > Seeing balance_pgdat() and trace log, I guess it does > > wake up > > shrink_zone(zone=0(DMA?)) => nothing to reclaim. > shrink_slab() > shrink_zone(zone=1(DMA32?)) => reclaim 32,32,31 pages > shrink_slab() > shrink_zone(zone=2(NORMAL?)) => reclaim 13 pages. > srhink_slab() > > sleep or retry. > > Why shrink_slab() need to be called frequently like this ? > > BTW. I'm sorry if I miss something ...Why only kswapd reclaims memory > while 'dd' operation ? (no direct relcaim by dd.) > Is this log record cpu hog after 'dd' ? report-dd.xz is while_ dd. report-normal.xz - some time after > Thanks, > -Kame > > > > > > > > > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . 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