Subject: + mm-vmscan-do-not-scale-writeback-pages-when-deciding-whether-to-set-zone_writeback.patch added to -mm tree To: mgorman@xxxxxxx,david@xxxxxxxxxxxxx,hannes@xxxxxxxxxxx,kamezawa.hiroyu@xxxxxxxxxxxxxx,mhocko@xxxxxxx,riel@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 26 Jun 2013 12:44:14 -0700 The patch titled Subject: mm: vmscan: do not scale writeback pages when deciding whether to set ZONE_WRITEBACK has been added to the -mm tree. Its filename is mm-vmscan-do-not-scale-writeback-pages-when-deciding-whether-to-set-zone_writeback.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mel Gorman <mgorman@xxxxxxx> Subject: mm: vmscan: do not scale writeback pages when deciding whether to set ZONE_WRITEBACK After the patch "mm: vmscan: Flatten kswapd priority loop" was merged the scanning priority of kswapd changed. The priority now raises until it is scanning enough pages to meet the high watermark. shrink_inactive_list sets ZONE_WRITEBACK if a number of pages were encountered under writeback but this value is scaled based on the priority. As kswapd frequently scans with a higher priority now it is relatively easy to set ZONE_WRITEBACK. This patch removes the scaling and treates writeback pages similar to how it treats unqueued dirty pages and congested pages. The user-visible effect should be that kswapd will writeback fewer pages from reclaim context. Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff -puN mm/vmscan.c~mm-vmscan-do-not-scale-writeback-pages-when-deciding-whether-to-set-zone_writeback mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-do-not-scale-writeback-pages-when-deciding-whether-to-set-zone_writeback +++ a/mm/vmscan.c @@ -1477,25 +1477,11 @@ shrink_inactive_list(unsigned long nr_to * as there is no guarantee the dirtying process is throttled in the * same way balance_dirty_pages() manages. * - * This scales the number of dirty pages that must be under writeback - * before a zone gets flagged ZONE_WRITEBACK. It is a simple backoff - * function that has the most effect in the range DEF_PRIORITY to - * DEF_PRIORITY-2 which is the priority reclaim is considered to be - * in trouble and reclaim is considered to be in trouble. - * - * DEF_PRIORITY 100% isolated pages must be PageWriteback to throttle - * DEF_PRIORITY-1 50% must be PageWriteback - * DEF_PRIORITY-2 25% must be PageWriteback, kswapd in trouble - * ... - * DEF_PRIORITY-6 For SWAP_CLUSTER_MAX isolated pages, throttle if any - * isolated page is PageWriteback - * * Once a zone is flagged ZONE_WRITEBACK, kswapd will count the number * of pages under pages flagged for immediate reclaim and stall if any * are encountered in the nr_immediate check below. */ - if (nr_writeback && nr_writeback >= - (nr_taken >> (DEF_PRIORITY - sc->priority))) + if (nr_writeback && nr_writeback == nr_taken) zone_set_flag(zone, ZONE_WRITEBACK); /* _ Patches currently in -mm which might be from mgorman@xxxxxxx are linux-next.patch mm-page_alloc-factor-out-setting-of-pcp-high-and-pcp-batch.patch mm-page_alloc-prevent-concurrent-updaters-of-pcp-batch-and-high.patch mm-page_alloc-insert-memory-barriers-to-allow-async-update-of-pcp-batch-and-high.patch mm-page_alloc-protect-pcp-batch-accesses-with-access_once.patch mm-page_alloc-convert-zone_pcp_update-to-rely-on-memory-barriers-instead-of-stop_machine.patch mm-page_alloc-when-handling-percpu_pagelist_fraction-dont-unneedly-recalulate-high.patch mm-page_alloc-factor-setup_pageset-into-pageset_init-and-pageset_set_batch.patch mm-page_alloc-relocate-comment-to-be-directly-above-code-it-refers-to.patch mm-page_alloc-factor-zone_pageset_init-out-of-setup_zone_pageset.patch mm-page_alloc-in-zone_pcp_update-uze-zone_pageset_init.patch mm-page_alloc-rename-setup_pagelist_highmark-to-match-naming-of-pageset_set_batch.patch mm-vmscan-limit-the-number-of-pages-kswapd-reclaims-at-each-priority.patch mm-vmscan-obey-proportional-scanning-requirements-for-kswapd.patch mm-vmscan-flatten-kswapd-priority-loop.patch mm-vmscan-decide-whether-to-compact-the-pgdat-based-on-reclaim-progress.patch mm-vmscan-do-not-allow-kswapd-to-scan-at-maximum-priority.patch mm-vmscan-have-kswapd-writeback-pages-based-on-dirty-pages-encountered-not-priority.patch mm-vmscan-block-kswapd-if-it-is-encountering-pages-under-writeback.patch mm-vmscan-block-kswapd-if-it-is-encountering-pages-under-writeback-fix.patch mm-vmscan-block-kswapd-if-it-is-encountering-pages-under-writeback-fix-2.patch mm-vmscan-check-if-kswapd-should-writepage-once-per-pgdat-scan.patch mm-vmscan-move-logic-from-balance_pgdat-to-kswapd_shrink_zone.patch mm-vmscan-stall-page-reclaim-and-writeback-pages-based-on-dirty-writepage-pages-encountered-v3.patch mm-vmscan-stall-page-reclaim-after-a-list-of-pages-have-been-processed-v3.patch mm-vmscan-set-zone-flags-before-blocking.patch mm-vmscan-move-direct-reclaim-wait_iff_congested-into-shrink_list.patch mm-vmscan-treat-pages-marked-for-immediate-reclaim-as-zone-congestion.patch mm-vmscan-take-page-buffers-dirty-and-locked-state-into-account-v3.patch fs-nfs-inform-the-vm-about-pages-being-committed-or-unstable.patch mm-add-tracepoints-for-lru-activation-and-insertions.patch mm-pagevec-defer-deciding-what-lru-to-add-a-page-to-until-pagevec-drain-time.patch mm-activate-pagelru-pages-on-mark_page_accessed-if-page-is-on-local-pagevec.patch mm-remove-lru-parameter-from-__pagevec_lru_add-and-remove-parts-of-pagevec-api.patch mm-remove-lru-parameter-from-__lru_cache_add-and-lru_cache_add_lru.patch mm-remove-lru-parameter-from-__lru_cache_add-and-lru_cache_add_lru-fix.patch mm-remove-lru-parameter-from-__lru_cache_add-and-lru_cache_add_lru-fix-2.patch mm-fix-the-tlb-range-flushed-when-__tlb_remove_page-runs-out-of-slots.patch mm-introduce-helper-function-mem_init_print_info-to-simplify-mem_init.patch mm-kill-global-variable-num_physpages.patch documentation-update-address_space_operations.patch documentation-document-the-is_dirty_writeback-aops-callback.patch fs-bump-inode-and-dentry-counters-to-long.patch super-fix-calculation-of-shrinkable-objects-for-small-numbers.patch dcache-convert-dentry_statnr_unused-to-per-cpu-counters.patch dentry-move-to-per-sb-lru-locks.patch dcache-remove-dentries-from-lru-before-putting-on-dispose-list.patch mm-new-shrinker-api.patch shrinker-convert-superblock-shrinkers-to-new-api.patch list-add-a-new-lru-list-type.patch inode-convert-inode-lru-list-to-generic-lru-list-code.patch dcache-convert-to-use-new-lru-list-infrastructure.patch list_lru-per-node-list-infrastructure.patch list_lru-per-node-api.patch shrinker-add-node-awareness.patch vmscan-per-node-deferred-work.patch fs-convert-inode-and-dentry-shrinking-to-be-node-aware.patch xfs-convert-buftarg-lru-to-generic-code.patch xfs-rework-buffer-dispose-list-tracking.patch xfs-convert-dquot-cache-lru-to-list_lru.patch fs-convert-fs-shrinkers-to-new-scan-count-api.patch drivers-convert-shrinkers-to-new-count-scan-api.patch i915-bail-out-earlier-when-shrinker-cannot-acquire-mutex.patch shrinker-convert-remaining-shrinkers-to-count-scan-api.patch hugepage-convert-huge-zero-page-shrinker-to-new-shrinker-api.patch shrinker-kill-old-shrink-api.patch list_lru-dynamically-adjust-node-arrays.patch zbud-add-to-mm.patch zswap-add-to-mm.patch zswap-add-documentation.patch mm-vmscan-avoid-direct-reclaim-scanning-at-maximum-priority.patch mm-vmscan-do-not-scale-writeback-pages-when-deciding-whether-to-set-zone_writeback.patch mm-memmap_init_zone-performance-improvement.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html