The patch titled
Do not disable interrupts when reading min_free_kbytes
has been added to the -mm tree. Its filename is
do-not-disable-interrupts-when-reading-min_free_kbytes.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Do not disable interrupts when reading min_free_kbytes
From: Mel Gorman <mel@xxxxxxxxx>
The sysctl handler for min_free_kbytes calls setup_per_zone_pages_min() on
read or write. This function iterates through every zone and calls
spin_lock_irqsave() on the zone LRU lock. When reading min_free_kbytes,
this is a total waste of time that disables interrupts on the local
processor. It might even be noticable machines with large numbers of zones
if a process started constantly reading min_free_kbytes.
This patch only calls setup_per_zone_pages_min() only on write. Tested on
an x86 laptop and it did the right thing.
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Cc: Christoph Lameter <clameter@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletion(-)
diff -puN mm/page_alloc.c~do-not-disable-interrupts-when-reading-min_free_kbytes mm/page_alloc.c
--- a/mm/page_alloc.c~do-not-disable-interrupts-when-reading-min_free_kbytes
+++ a/mm/page_alloc.c
@@ -3836,7 +3836,8 @@ int min_free_kbytes_sysctl_handler(ctl_t
struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
proc_dointvec(table, write, file, buffer, length, ppos);
- setup_per_zone_pages_min();
+ if (write)
+ setup_per_zone_pages_min();
return 0;
}
_
Patches currently in -mm which might be from mel@xxxxxxxxx are
add-a-bitmap-that-is-used-to-track-flags-affecting-a-block-of-pages.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated-fix.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-low-memory-that-may-be-migrated.patch
split-the-free-lists-for-movable-and-unmovable-allocations.patch
choose-pages-from-the-per-cpu-list-based-on-migration-type.patch
add-a-configure-option-to-group-pages-by-mobility.patch
drain-per-cpu-lists-when-high-order-allocations-fail.patch
move-free-pages-between-lists-on-steal.patch
move-free-pages-between-lists-on-steal-fix.patch
move-free-pages-between-lists-on-steal-fix-2.patch
move-free-pages-between-lists-on-steal-avoid-unsafe-use-of-struct-pages-in-move_freepages-when-config_holes_in_zone-is-set.patch
group-short-lived-and-reclaimable-kernel-allocations.patch
group-high-order-atomic-allocations.patch
bias-the-placement-of-kernel-pages-at-lower-pfns.patch
be-more-agressive-about-stealing-when-migrate_reclaimable-allocations-fallback.patch
fix-corruption-of-memmap-on-ia64-sparsemem-when-mem_section-is-not-a-power-of-2.patch
create-the-zone_movable-zone.patch
allow-huge-page-allocations-to-use-gfp_high_movable.patch
x86-specify-amount-of-kernel-memory-at-boot-time.patch
ppc-and-powerpc-specify-amount-of-kernel-memory-at-boot-time.patch
x86_64-specify-amount-of-kernel-memory-at-boot-time.patch
ia64-specify-amount-of-kernel-memory-at-boot-time.patch
add-documentation-for-additional-boot-parameter-and-sysctl.patch
lumpy-reclaim-v4.patch
lumpy-back-out-removal-of-active-check-in-isolate_lru_pages.patch
lumpy-only-count-taken-pages-as-scanned.patch
add-pfn_valid_within-helper-for-sub-max_order-hole-detection.patch
anti-fragmentation-switch-over-to-pfn_valid_within.patch
lumpy-move-to-using-pfn_valid_within.patch
bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks.patch
bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks-tidy.patch
do-not-disable-interrupts-when-reading-min_free_kbytes.patch
ext2-reservations.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated-swap-prefetch.patch
add-debugging-aid-for-memory-initialisation-problems.patch
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