From a8d0143730d7b42c9fe6d1435d92ecce6863a62a Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 14 Jan 2016 15:20:15 -0800 Subject: [PATCH] mm: page_alloc: generalize the dirty balance reserve The dirty balance reserve that dirty throttling has to consider is merely memory not available to userspace allocations. There is nothing writeback-specific about it. Generalize the name so that it's reusable outside of that context. Signed-off-by: Johannes Weiner Cc: Rik van Riel Cc: Mel Gorman Acked-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 6 +++--- include/linux/swap.h | 1 - mm/page-writeback.c | 14 ++++++++++++-- mm/page_alloc.c | 21 +++------------------ 4 files changed, 18 insertions(+), 24 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 3b6fb71bbeb31..33bb1b19273e3 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -356,10 +356,10 @@ struct zone { struct per_cpu_pageset __percpu *pageset; /* - * This is a per-zone reserve of pages that should not be - * considered dirtyable memory. + * This is a per-zone reserve of pages that are not available + * to userspace allocations. */ - unsigned long dirty_balance_reserve; + unsigned long totalreserve_pages; #ifndef CONFIG_SPARSEMEM /* diff --git a/include/linux/swap.h b/include/linux/swap.h index 7ba7dccaf0e7e..066bd21765ad7 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -287,7 +287,6 @@ static inline void workingset_node_shadows_dec(struct radix_tree_node *node) /* linux/mm/page_alloc.c */ extern unsigned long totalram_pages; extern unsigned long totalreserve_pages; -extern unsigned long dirty_balance_reserve; extern unsigned long nr_free_buffer_pages(void); extern unsigned long nr_free_pagecache_pages(void); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d15d88c8efa1e..6fe7d15bd1f78 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -278,7 +278,12 @@ static unsigned long zone_dirtyable_memory(struct zone *zone) unsigned long nr_pages; nr_pages = zone_page_state(zone, NR_FREE_PAGES); - nr_pages -= min(nr_pages, zone->dirty_balance_reserve); + /* + * Pages reserved for the kernel should not be considered + * dirtyable, to prevent a situation where reclaim has to + * clean pages in order to balance the zones. + */ + nr_pages -= min(nr_pages, zone->totalreserve_pages); nr_pages += zone_page_state(zone, NR_INACTIVE_FILE); nr_pages += zone_page_state(zone, NR_ACTIVE_FILE); @@ -332,7 +337,12 @@ static unsigned long global_dirtyable_memory(void) unsigned long x; x = global_page_state(NR_FREE_PAGES); - x -= min(x, dirty_balance_reserve); + /* + * Pages reserved for the kernel should not be considered + * dirtyable, to prevent a situation where reclaim has to + * clean pages in order to balance the zones. + */ + x -= min(x, totalreserve_pages); x += global_page_state(NR_INACTIVE_FILE); x += global_page_state(NR_ACTIVE_FILE); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2a6fe377cafcb..1e9a560654002 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -114,13 +114,6 @@ static DEFINE_SPINLOCK(managed_page_count_lock); unsigned long totalram_pages __read_mostly; unsigned long totalreserve_pages __read_mostly; unsigned long totalcma_pages __read_mostly; -/* - * When calculating the number of globally allowed dirty pages, there - * is a certain number of per-zone reserves that should not be - * considered dirtyable memory. This is the sum of those reserves - * over all existing zones that contribute dirtyable memory. - */ -unsigned long dirty_balance_reserve __read_mostly; int percpu_pagelist_fraction; gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; @@ -5942,20 +5935,12 @@ static void calculate_totalreserve_pages(void) if (max > zone->managed_pages) max = zone->managed_pages; + + zone->totalreserve_pages = max; + reserve_pages += max; - /* - * Lowmem reserves are not available to - * GFP_HIGHUSER page cache allocations and - * kswapd tries to balance zones to their high - * watermark. As a result, neither should be - * regarded as dirtyable memory, to prevent a - * situation where reclaim has to clean pages - * in order to balance the zones. - */ - zone->dirty_balance_reserve = max; } } - dirty_balance_reserve = reserve_pages; totalreserve_pages = reserve_pages; } -- 2.39.2