[PATCH] zoned vm counters: zone_reclaim: remove /proc/sys/vm/zone_reclaim_interval
The zone_reclaim_interval was necessary because we were not able to determine
how many unmapped pages exist in a zone. Therefore we had to scan in
intervals to figure out if any pages were unmapped.
With the zoned counters and NR_ANON_PAGES we now know the number of pagecache
pages and the number of mapped pages in a zone. So we can simply skip the
reclaim if there is an insufficient number of unmapped pages. We use
SWAP_CLUSTER_MAX as the boundary.
Drop all support for /proc/sys/vm/zone_reclaim_interval.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 2dc246a..86754eb 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -28,7 +28,6 @@
- block_dump
- drop-caches
- zone_reclaim_mode
-- zone_reclaim_interval
- panic_on_oom
==============================================================
@@ -167,18 +166,6 @@
shrink operation is global, may take a long time and free slabs
in all nodes of the system.
-================================================================
-
-zone_reclaim_interval:
-
-The time allowed for off node allocations after zone reclaim
-has failed to reclaim enough pages to allow a local allocation.
-
-Time is set in seconds and set by default to 30 seconds.
-
-Reduce the interval if undesired off node allocations occur. However, too
-frequent scans will have a negative impact onoff node allocation performance.
-
=============================================================
panic_on_oom
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4833abd..839e9a0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -178,12 +178,6 @@
/* Zone statistics */
atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
- /*
- * timestamp (in jiffies) of the last zone reclaim that did not
- * result in freeing of pages. This is used to avoid repeated scans
- * if all memory in the zone is in use.
- */
- unsigned long last_unsuccessful_zone_reclaim;
/*
* prev_priority holds the scanning priority for this zone. It is
diff --git a/include/linux/swap.h b/include/linux/swap.h
index c41e2d6..cf6ca6e 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -189,7 +189,6 @@
#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
-extern int zone_reclaim_interval;
extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
#else
#define zone_reclaim_mode 0
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 93a2c53..ee0db45 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -933,15 +933,6 @@
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
- {
- .ctl_name = VM_ZONE_RECLAIM_INTERVAL,
- .procname = "zone_reclaim_interval",
- .data = &zone_reclaim_interval,
- .maxlen = sizeof(zone_reclaim_interval),
- .mode = 0644,
- .proc_handler = &proc_dointvec_jiffies,
- .strategy = &sysctl_jiffies,
- },
#endif
#ifdef CONFIG_X86_32
{
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2f03901..0960846 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1518,11 +1518,6 @@
#define RECLAIM_SLAB (1<<3) /* Do a global slab shrink if the zone is out of memory */
/*
- * Mininum time between zone reclaim scans
- */
-int zone_reclaim_interval __read_mostly = 30*HZ;
-
-/*
* Priority for ZONE_RECLAIM. This determines the fraction of pages
* of a node considered for each zone_reclaim. 4 scans 1/16th of
* a zone.
@@ -1587,16 +1582,6 @@
p->reclaim_state = NULL;
current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
-
- if (nr_reclaimed == 0) {
- /*
- * We were unable to reclaim enough pages to stay on node. We
- * now allow off node accesses for a certain time period before
- * trying again to reclaim pages from the local zone.
- */
- zone->last_unsuccessful_zone_reclaim = jiffies;
- }
-
return nr_reclaimed >= nr_pages;
}
@@ -1606,13 +1591,17 @@
int node_id;
/*
- * Do not reclaim if there was a recent unsuccessful attempt at zone
- * reclaim. In that case we let allocations go off node for the
- * zone_reclaim_interval. Otherwise we would scan for each off-node
- * page allocation.
+ * Do not reclaim if there are not enough reclaimable pages in this
+ * zone that would satify this allocations.
+ *
+ * All unmapped pagecache pages are reclaimable.
+ *
+ * Both counters may be temporarily off a bit so we use
+ * SWAP_CLUSTER_MAX as the boundary. It may also be good to
+ * leave a few frequently used unmapped pagecache pages around.
*/
- if (time_before(jiffies,
- zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
+ if (zone_page_state(zone, NR_FILE_PAGES) -
+ zone_page_state(zone, NR_FILE_MAPPED) < SWAP_CLUSTER_MAX)
return 0;
/*