Make zonelist policy selectable from sysctl.
Assume 2 node NUMA, only node(0) has ZONE_DMA (ZONE_DMA32).
In this case, default (node0's) zonelist order is
Node(0)'s NORMAL -> Node(0)'s DMA -> Node(1)"s NORMAL.
This means Node(0)'s DMA is used before Node(1)'s NORMAL.
In some server, some application uses large memory allcation.
This exhaust memory in the above order.
Then....sometimes OOM_KILL will occur when 32bit device requires memory.
This patch adds sysctl for rebuilding zonelist after boot and doesn't change
default zonelist order.
command:
%echo 0 > /proc/sys/vm/better_locality
Will rebuild zonelist in following order.
Node(0)'s NORMAL -> Node(1)'s NORMAL -> Node(0)'s DMA.
if set better_locality == 1 (default), zonelist is
Node(0)'s NORMAL -> Node(0)'s DMA -> Node(1)'s NORMAL.
Maybe useful in some users with heavy memory pressure and mlocks.
Tested under ia64 2 node NUMA against 2.6.21-rc7.. works well.
Signed-Off-By: KAMEZAWA Hiroyuki <[email protected]>
Index: linux-2.6.21-rc7/kernel/sysctl.c
===================================================================
--- linux-2.6.21-rc7.orig/kernel/sysctl.c
+++ linux-2.6.21-rc7/kernel/sysctl.c
@@ -76,6 +76,9 @@ extern int pid_max_min, pid_max_max;
extern int sysctl_drop_caches;
extern int percpu_pagelist_fraction;
extern int compat_log;
+#ifdef CONFIG_NUMA
+extern int sysctl_better_locality;
+#endif
/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
static int maxolduid = 65535;
@@ -845,6 +848,15 @@ static ctl_table vm_table[] = {
.extra1 = &zero,
.extra2 = &one_hundred,
},
+ {
+ .ctl_name = VM_BETTER_LOCALITY,
+ .procname = "better_locality",
+ .data = &sysctl_better_locality,
+ .maxlen = sizeof(sysctl_better_locality),
+ .mode = 0644,
+ .proc_handler = &sysctl_better_locality_handler,
+ .strategy = &sysctl_intvec,
+ },
#endif
#if defined(CONFIG_X86_32) || \
(defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
Index: linux-2.6.21-rc7/mm/page_alloc.c
===================================================================
--- linux-2.6.21-rc7.orig/mm/page_alloc.c
+++ linux-2.6.21-rc7/mm/page_alloc.c
@@ -1670,7 +1670,7 @@ static int __meminit build_zonelists_nod
#ifdef CONFIG_NUMA
#define MAX_NODE_LOAD (num_online_nodes())
-static int __meminitdata node_load[MAX_NUMNODES];
+static int node_load[MAX_NUMNODES];
/**
* find_next_best_node - find the next node that should appear in a given node's fallback list
* @node: node whose fallback list we're appending
@@ -1685,7 +1685,7 @@ static int __meminitdata node_load[MAX_N
* on them otherwise.
* It returns -1 if no node is found.
*/
-static int __meminit find_next_best_node(int node, nodemask_t *used_node_mask)
+static int find_next_best_node(int node, nodemask_t *used_node_mask)
{
int n, val;
int min_val = INT_MAX;
@@ -1731,7 +1731,10 @@ static int __meminit find_next_best_node
return best_node;
}
-static void __meminit build_zonelists(pg_data_t *pgdat)
+/*
+ * Build zonelists based on node locality.
+ */
+static void build_zonelists_locality_aware(pg_data_t *pgdat)
{
int j, node, local_node;
enum zone_type i;
@@ -1780,6 +1783,78 @@ static void __meminit build_zonelists(pg
}
}
+/*
+ * Build zonelist based on zone priority.
+ */
+static int node_order[MAX_NUMNODES];
+static void build_zonelists_zone_aware(pg_data_t *pgdat)
+{
+ int i, j, pos, zone_type, node, load;
+ nodemask_t used_mask;
+ int local_node, prev_node;
+ struct zone *z;
+ struct zonelist *zonelist;
+
+ for (i = 0; i < MAX_NR_ZONES; i++) {
+ zonelist = pgdat->node_zonelists + i;
+ zonelist->zones[0] = NULL;
+ }
+ memset(node_order, 0, sizeof(node_order));
+ local_node = pgdat->node_id;
+ load = num_online_nodes();
+ prev_node = local_node;
+ nodes_clear(used_mask);
+ j = 0;
+ while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
+ int distance = node_distance(local_node, node);
+ if (distance > RECLAIM_DISTANCE)
+ zone_reclaim_mode = 1;
+ if (distance != node_distance(local_node, prev_node))
+ node_load[node] = load;
+ node_order[j++] = node;
+ prev_node = node;
+ load--;
+ }
+ /* calculate node order */
+ for (i = 0; i < MAX_NR_ZONES; i++) {
+ zonelist = pgdat->node_zonelists + i;
+ pos = 0;
+ for (zone_type = i; zone_type >= 0; zone_type--) {
+ for (j = 0; j < num_online_nodes(); j++) {
+ node = node_order[j];
+ z = &NODE_DATA(node)->node_zones[zone_type];
+ if (populated_zone(z))
+ zonelist->zones[pos++] = z;
+ }
+ }
+ zonelist->zones[pos] = NULL;
+ }
+}
+
+int sysctl_better_locality = 1;
+
+static void build_zonelists(pg_data_t *pgdat)
+{
+ if (sysctl_better_locality) {
+ build_zonelists_locality_aware(pgdat);
+ } else {
+ build_zonelists_zone_aware(pgdat);
+ }
+}
+
+int sysctl_better_locality_handler(ctl_table *table, int write,
+ struct file *file, void __user *buffer, size_t *length,
+ loff_t *ppos)
+{
+ int oldval = sysctl_better_locality;
+ proc_dointvec_minmax(table, write, file, buffer, length, ppos);
+ if (write) {
+ if (oldval != sysctl_better_locality)
+ build_all_zonelists();
+ }
+ return 0;
+}
+
/* Construct the zonelist performance cache - see further mmzone.h */
static void __meminit build_zonelist_cache(pg_data_t *pgdat)
{
@@ -1847,7 +1922,7 @@ static void __meminit build_zonelist_cac
#endif /* CONFIG_NUMA */
/* return values int ....just for stop_machine_run() */
-static int __meminit __build_all_zonelists(void *dummy)
+static int __build_all_zonelists(void *dummy)
{
int nid;
@@ -1858,12 +1933,13 @@ static int __meminit __build_all_zonelis
return 0;
}
-void __meminit build_all_zonelists(void)
+void build_all_zonelists(void)
{
if (system_state == SYSTEM_BOOTING) {
__build_all_zonelists(NULL);
cpuset_init_current_mems_allowed();
} else {
+ memset(node_load, 0, sizeof(node_load));
/* we have to stop all cpus to guaranntee there is no user
of zonelist */
stop_machine_run(__build_all_zonelists, NULL, NR_CPUS);
Index: linux-2.6.21-rc7/include/linux/mmzone.h
===================================================================
--- linux-2.6.21-rc7.orig/include/linux/mmzone.h
+++ linux-2.6.21-rc7/include/linux/mmzone.h
@@ -563,6 +563,9 @@ int sysctl_min_unmapped_ratio_sysctl_han
int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
struct file *, void __user *, size_t *, loff_t *);
+extern int sysctl_better_locality_handler(struct ctl_table *, int,
+ struct file *, void __user *, size_t *, loff_t *);
+
#include <linux/topology.h>
/* Returns the number of the current Node. */
#ifndef numa_node_id
Index: linux-2.6.21-rc7/include/linux/sysctl.h
===================================================================
--- linux-2.6.21-rc7.orig/include/linux/sysctl.h
+++ linux-2.6.21-rc7/include/linux/sysctl.h
@@ -207,6 +207,7 @@ enum
VM_PANIC_ON_OOM=33, /* panic at out-of-memory */
VM_VDSO_ENABLED=34, /* map VDSO into new processes? */
VM_MIN_SLAB=35, /* Percent pages ignored by zone reclaim */
+ VM_BETTER_LOCALITY=36, /* create locality-preference zonelist */
/* s390 vm cmm sysctls */
VM_CMM_PAGES=1111,
-
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