The patch titled
mm: test and set zone reclaim lock before starting reclaim
has been added to the -mm tree. Its filename is
mm-test-and-set-zone-reclaim-lock-before-starting.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: mm: test and set zone reclaim lock before starting reclaim
From: David Rientjes <rientjes@xxxxxxxxxx>
Introduces new zone flag interface for testing and setting flags:
int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is
called, this flag is test and set before starting zone reclaim. Zone reclaim
starts in __alloc_pages() when a zone's watermark fails and the system is in
zone_reclaim_mode. If it's already in reclaim, there's no need to start again
so it is simply considered full for that allocation attempt.
There is a change of behavior with regard to concurrent zone shrinking. It is
now possible for try_to_free_pages() or kswapd to already be shrinking a
particular zone when __alloc_pages() starts zone reclaim. In this case, it is
possible for two concurrent threads to invoke shrink_zone() for a single zone.
This change forbids a zone to be in zone reclaim twice, which was always the
behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking
when starting zone reclaim.
Cc: Andrea Arcangeli <andrea@xxxxxxx>
Cc: Christoph Lameter <clameter@xxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN include/linux/mmzone.h~mm-test-and-set-zone-reclaim-lock-before-starting include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-test-and-set-zone-reclaim-lock-before-starting
+++ a/include/linux/mmzone.h
@@ -353,6 +353,10 @@ static inline void zone_set_flag(struct
{
set_bit(flag, &zone->flags);
}
+static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
+{
+ return test_and_set_bit(flag, &zone->flags);
+}
static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
{
clear_bit(flag, &zone->flags);
diff -puN mm/vmscan.c~mm-test-and-set-zone-reclaim-lock-before-starting mm/vmscan.c
--- a/mm/vmscan.c~mm-test-and-set-zone-reclaim-lock-before-starting
+++ a/mm/vmscan.c
@@ -1112,8 +1112,6 @@ static unsigned long shrink_zone(int pri
unsigned long nr_to_scan;
unsigned long nr_reclaimed = 0;
- zone_set_flag(zone, ZONE_RECLAIM_LOCKED);
-
/*
* Add one to `nr_to_scan' just to make sure that the kernel will
* slowly sift through the active list.
@@ -1152,8 +1150,6 @@ static unsigned long shrink_zone(int pri
}
throttle_vm_writeout(sc->gfp_mask);
-
- zone_clear_flag(zone, ZONE_RECLAIM_LOCKED);
return nr_reclaimed;
}
@@ -1932,6 +1928,7 @@ static int __zone_reclaim(struct zone *z
int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
{
int node_id;
+ int ret;
/*
* Zone reclaim reclaims unmapped file backed pages and
@@ -1949,13 +1946,13 @@ int zone_reclaim(struct zone *zone, gfp_
<= zone->min_slab_pages)
return 0;
+ if (zone_is_all_unreclaimable(zone))
+ return 0;
+
/*
- * Avoid concurrent zone reclaims, do not reclaim in a zone that does
- * not have reclaimable pages and if we should not delay the allocation
- * then do not scan.
+ * Do not scan if the allocation should not be delayed.
*/
- if (!(gfp_mask & __GFP_WAIT) || zone_is_all_unreclaimable(zone) ||
- zone_is_reclaim_locked(zone) || (current->flags & PF_MEMALLOC))
+ if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC))
return 0;
/*
@@ -1967,6 +1964,12 @@ int zone_reclaim(struct zone *zone, gfp_
node_id = zone_to_nid(zone);
if (node_state(node_id, N_CPU) && node_id != numa_node_id())
return 0;
- return __zone_reclaim(zone, gfp_mask, order);
+
+ if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED))
+ return 0;
+ ret = __zone_reclaim(zone, gfp_mask, order);
+ zone_clear_flag(zone, ZONE_RECLAIM_LOCKED);
+
+ return ret;
}
#endif
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
maps2-uninline-some-functions-in-the-page-walker.patch
maps2-eliminate-the-pmd_walker-struct-in-the-page-walker.patch
maps2-remove-vma-from-args-in-the-page-walker.patch
maps2-propagate-errors-from-callback-in-page-walker.patch
maps2-add-callbacks-for-each-level-to-page-walker.patch
maps2-move-the-page-walker-code-to-lib.patch
maps2-simplify-interdependence-of-proc-pid-maps-and-smaps.patch
maps2-move-clear_refs-code-to-task_mmuc.patch
maps2-regroup-task_mmu-by-interface.patch
maps2-make-proc-pid-smaps-optional-under-config_embedded.patch
maps2-make-proc-pid-clear_refs-option-under-config_embedded.patch
maps2-add-proc-pid-pagemap-interface.patch
maps2-add-proc-kpagemap-interface.patch
oom-move-prototypes-to-appropriate-header-file.patch
oom-move-prototypes-to-appropriate-header-file-fix.patch
oom-move-constraints-to-enum.patch
oom-change-all_unreclaimable-zone-member-to-flags.patch
oom-change-all_unreclaimable-zone-member-to-flags-fix.patch
oom-add-per-zone-locking.patch
oom-serialize-out-of-memory-calls.patch
oom-add-oom_kill_allocating_task-sysctl.patch
oom-suppress-extraneous-stack-and-memory-dump.patch
oom-compare-cpuset-mems_allowed-instead-of-exclusive.patch
oom-do-not-take-callback_mutex.patch
oom-do-not-take-callback_mutex-fix.patch
oom-prevent-including-schedh-in-header-file.patch
oom-add-header-file-to-kbuild-as-unifdef.patch
oom-convert-zone_scan_lock-from-mutex-to-spinlock.patch
mm-test-and-set-zone-reclaim-lock-before-starting.patch
add-a-missing-00-index-file-for-documentation-vm-fix.patch
memory-controller-add-documentation.patch
memory-controller-resource-counters-v7.patch
memory-controller-resource-counters-v7-fix.patch
memory-controller-containers-setup-v7.patch
memory-controller-accounting-setup-v7.patch
memory-controller-memory-accounting-v7.patch
memory-controller-task-migration-v7.patch
memory-controller-add-per-container-lru-and-reclaim-v7.patch
memory-controller-add-per-container-lru-and-reclaim-v7-fix.patch
memory-controller-improve-user-interface.patch
memory-controller-oom-handling-v7.patch
memory-controller-oom-handling-v7-vs-oom-killer-stuff.patch
memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7.patch
memory-controller-add-switch-to-control-what-type-of-pages-to-limit-v7-fix-2.patch
memory-controller-make-page_referenced-container-aware-v7.patch
memory-controller-make-charging-gfp-mask-aware.patch
memcontrol-move-mm_cgroup-to-header-file.patch
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