Subject: + mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments.patch added to -mm tree To: nasa4836@xxxxxxxxx,aquini@xxxxxxxxxx,riel@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Mon, 19 May 2014 15:17:04 -0700 The patch titled Subject: mm/vmscan.c: use DIV_ROUND_UP for calculation of zone's balance_gap and correct comments. has been added to the -mm tree. Its filename is mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments.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: Jianyu Zhan <nasa4836@xxxxxxxxx> Subject: mm/vmscan.c: use DIV_ROUND_UP for calculation of zone's balance_gap and correct comments. Currently, we use (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / KSWAPD_ZONE_BALANCE_GAP_RATIO to avoid a zero gap value. It's better to use DIV_ROUND_UP macro for neater code and clear meaning. Besides, the gap value is calculated against the per-zone "managed pages", not "present pages". This patch also corrects the comment and do some rephrasing. Signed-off-by: Jianyu Zhan <nasa4836@xxxxxxxxx> Acked-by: Rik van Riel <riel@xxxxxxxxxx> Acked-by: Rafael Aquini <aquini@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/swap.h | 8 ++++---- mm/vmscan.c | 10 ++++------ 2 files changed, 8 insertions(+), 10 deletions(-) diff -puN include/linux/swap.h~mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments include/linux/swap.h --- a/include/linux/swap.h~mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments +++ a/include/linux/swap.h @@ -166,10 +166,10 @@ enum { #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX /* - * Ratio between the present memory in the zone and the "gap" that - * we're allowing kswapd to shrink in addition to the per-zone high - * wmark, even for zones that already have the high wmark satisfied, - * in order to provide better per-zone lru behavior. We are ok to + * Ratio between zone->managed_pages and the "gap" that above the per-zone + * "high_wmark". While balancing nodes, We allow kswapd to shrink zones that + * do not meet the (high_wmark + gap) watermark, even which already met the + * high_wmark, in order to provide better per-zone lru behavior. We are ok to * spend not more than 1% of the memory for this zone balancing "gap". */ #define KSWAPD_ZONE_BALANCE_GAP_RATIO 100 diff -puN mm/vmscan.c~mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments mm/vmscan.c --- a/mm/vmscan.c~mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments +++ a/mm/vmscan.c @@ -2298,9 +2298,8 @@ static inline bool compaction_ready(stru * there is a buffer of free pages available to give compaction * a reasonable chance of completing and allocating the page */ - balance_gap = min(low_wmark_pages(zone), - (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / - KSWAPD_ZONE_BALANCE_GAP_RATIO); + balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP( + zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO)); watermark = high_wmark_pages(zone) + balance_gap + (2UL << sc->order); watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, 0, 0); @@ -2952,9 +2951,8 @@ static bool kswapd_shrink_zone(struct zo * high wmark plus a "gap" where the gap is either the low * watermark or 1% of the zone, whichever is smaller. */ - balance_gap = min(low_wmark_pages(zone), - (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / - KSWAPD_ZONE_BALANCE_GAP_RATIO); + balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP( + zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO)); /* * If there is no low memory pressure or the zone is balanced then no _ Patches currently in -mm which might be from nasa4836@xxxxxxxxx are origin.patch mm-swapc-clean-up-lru_cache_add-functions.patch mm-swapc-introduce-put_refcounted_compound_page-helpers-for-spliting-put_compound_page.patch mm-swapc-split-put_compound_page-function.patch mm-introdule-compound_head_by_tail.patch mm-add-comment-for-__mod_zone_page_stat.patch mm-add-comment-for-__mod_zone_page_stat-checkpatch-fixes.patch mm-fold-mlocked_vma_newpage-into-its-only-call-site.patch mm-fold-mlocked_vma_newpage-into-its-only-call-site-checkpatch-fixes.patch mm-hugetlb-move-the-error-handle-logic-out-of-normal-code-path.patch mm-vmscanc-use-div_round_up-for-calculation-of-zones-balance_gap-and-correct-comments.patch linux-next.patch mm-memcontrol-clean-up-memcg-zoneinfo-lookup.patch mm-memcontrol-remove-unnecessary-memcg-argument-from-soft-limit-functions.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