The patch titled
Subject: mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request
has been added to the -mm tree. Its filename is
mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request.patch
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------------------------------------------------------
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: 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@xxxxxxx
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: <linux-api@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/sysctl/vm.txt | 5 ++---
include/linux/mmzone.h | 2 +-
mm/page_alloc.c | 25 ++++++++++++++-----------
3 files changed, 17 insertions(+), 15 deletions(-)
diff -puN Documentation/sysctl/vm.txt~mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request Documentation/sysctl/vm.txt
--- a/Documentation/sysctl/vm.txt~mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request
+++ a/Documentation/sysctl/vm.txt
@@ -312,8 +312,6 @@ The lowmem_reserve_ratio is an array. Yo
% 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
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 -puN include/linux/mmzone.h~mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request
+++ a/include/linux/mmzone.h
@@ -886,7 +886,7 @@ int min_free_kbytes_sysctl_handler(struc
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 -puN mm/page_alloc.c~mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request
+++ a/mm/page_alloc.c
@@ -204,17 +204,18 @@ static void __free_pages_ok(struct page
* 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);
@@ -6971,13 +6972,15 @@ static void setup_per_zone_lowmem_reserv
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;
}
}
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
mm-page_alloc-dont-reserve-zone_highmem-for-zone_movable-request.patch
mm-cma-manage-the-memory-of-the-cma-area-by-using-the-zone_movable.patch
mm-cma-remove-alloc_cma.patch
arm-cma-avoid-double-mapping-to-the-cma-area-if-config_highmem-=-y.patch
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