[PATCH v5 1/6] mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request
From: <hidden>
Date: 2016-08-29 05:07:53
Also in:
lkml
Subsystem:
memory management, memory management - core, memory management - mglru (multi-gen lru), memory management - page allocator, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Vlastimil Babka, Linus Torvalds
From: Joonsoo Kim <redacted> 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. 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 fix this situation by defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES and place "#ifdef" to right place. Signed-off-by: Joonsoo Kim <redacted> --- include/linux/mmzone.h | 2 +- mm/page_alloc.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index d572b78..e3f39af 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h@@ -877,7 +877,7 @@ 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 4f7d5d7..a8310de 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c@@ -198,17 +198,18 @@ 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, #endif #ifdef CONFIG_ZONE_DMA32 256, #endif -#ifdef CONFIG_HIGHMEM 32, +#ifdef CONFIG_HIGHMEM + INT_MAX, #endif - 32, + INT_MAX, }; EXPORT_SYMBOL(totalram_pages);
--
1.9.1
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