diff options
author | Joonsoo Kim <iamjoonsoo.kim@lge.com> | 2018-04-10 16:30:11 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-11 10:28:32 -0700 |
commit | d3cda2337bbc9edd2a26b83cb00eaa8c048ff274 (patch) | |
tree | 96e2745e71e23f92a7ce96b6a6b1eec3b69cd779 | |
parent | 94723aafb9e76414fada7c1c198733a86f01ea8f (diff) | |
download | op-kernel-dev-d3cda2337bbc9edd2a26b83cb00eaa8c048ff274.zip op-kernel-dev-d3cda2337bbc9edd2a26b83cb00eaa8c048ff274.tar.gz |
mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request
Freepage on ZONE_HIGHMEM doesn't work for kernel memory so it's not that
important to reserve. When ZONE_MOVABLE is used, this problem would
theorectically cause to decrease usable memory for GFP_HIGHUSER_MOVABLE
allocation request which is mainly used for page cache and anon page
allocation. So, fix it by setting 0 to
sysctl_lowmem_reserve_ratio[ZONE_HIGHMEM].
And, defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES - 1 size
makes code complex. For example, if there is highmem system, following
reserve ratio is activated for *NORMAL ZONE* which would be easyily
misleading people.
#ifdef CONFIG_HIGHMEM
32
#endif
This patch also fixes this situation by defining
sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES and place "#ifdef" to
right place.
Link: http://lkml.kernel.org/r/1504672525-17915-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | Documentation/sysctl/vm.txt | 5 | ||||
-rw-r--r-- | include/linux/mmzone.h | 2 | ||||
-rw-r--r-- | mm/page_alloc.c | 25 |
3 files changed, 17 insertions, 15 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index ff234d2..17256f2 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -312,8 +312,6 @@ The lowmem_reserve_ratio is an array. You can see them by reading this file. % cat /proc/sys/vm/lowmem_reserve_ratio 256 256 32 - -Note: # of this elements is one fewer than number of zones. Because the highest - zone's value is not necessary for following calculation. But, these values are not used directly. The kernel calculates # of protection pages for each zones from them. These are shown as array of protection pages @@ -364,7 +362,8 @@ As above expression, they are reciprocal number of ratio. pages of higher zones on the node. If you would like to protect more pages, smaller values are effective. -The minimum value is 1 (1/1 -> 100%). +The minimum value is 1 (1/1 -> 100%). The value less than 1 completely +disables protection of the pages. ============================================================== diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index a0c9e45..32699b2 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -885,7 +885,7 @@ int min_free_kbytes_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); -extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; +extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES]; int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b046678..34a4c12 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -205,17 +205,18 @@ static void __free_pages_ok(struct page *page, unsigned int order); * TBD: should special case ZONE_DMA32 machines here - in those we normally * don't need any ZONE_NORMAL reservation */ -int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { +int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = { #ifdef CONFIG_ZONE_DMA - 256, + [ZONE_DMA] = 256, #endif #ifdef CONFIG_ZONE_DMA32 - 256, + [ZONE_DMA32] = 256, #endif + [ZONE_NORMAL] = 32, #ifdef CONFIG_HIGHMEM - 32, + [ZONE_HIGHMEM] = 0, #endif - 32, + [ZONE_MOVABLE] = 0, }; EXPORT_SYMBOL(totalram_pages); @@ -7132,13 +7133,15 @@ static void setup_per_zone_lowmem_reserve(void) struct zone *lower_zone; idx--; - - if (sysctl_lowmem_reserve_ratio[idx] < 1) - sysctl_lowmem_reserve_ratio[idx] = 1; - lower_zone = pgdat->node_zones + idx; - lower_zone->lowmem_reserve[j] = managed_pages / - sysctl_lowmem_reserve_ratio[idx]; + + if (sysctl_lowmem_reserve_ratio[idx] < 1) { + sysctl_lowmem_reserve_ratio[idx] = 0; + lower_zone->lowmem_reserve[j] = 0; + } else { + lower_zone->lowmem_reserve[j] = + managed_pages / sysctl_lowmem_reserve_ratio[idx]; + } managed_pages += lower_zone->managed_pages; } } |