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SubjectRe: [PATCH] change global zonelist order v4 [1/2] change zonelist ordering.
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On Fri, 2007-04-27 at 15:04 +0900, KAMEZAWA Hiroyuki wrote:
> Make zonelist creation policy selectable from sysctl v4.
> Automatic configuration itself is provided by the next patch.
>
> [Description]
> Assume 2 node NUMA, only node(0) has ZONE_DMA.
> (ia64's ZONE_DMA is below 4GB...x86_64's ZONE_DMA32)
>
> In this case, current default (node0's) zonelist order is
>
> Node(0)'s NORMAL -> Node(0)'s DMA -> Node(1)"s NORMAL.
>
> This means Node(0)'s DMA will be used before Node(1)'s NORMAL.
>
> This patch changes *default* zone order to
>
> Node(0)'s NORMAL -> Node(1)'s NORMAL -> Node(0)'s DMA.
>
> But, if Node(0)'s memory is too small (near or below 4G), Node(0)'s process has
> to allocate its memory from Node(1) even if there are free memory in Node(0).
> Some applications/uses will dislike this.
> This patch adds a knob to change zonelist ordering.
>
> [What this patch adds]
>
> command:
> %echo N > /proc/sys/vm/numa_zonelist_order
>
> Will rebuild zonelist in following order(old style, NODE order).
>
> Node(0)'s NORMAL -> Node(0)'s DMA -> Node(0)'s NORMAL.
>
> means put more priority on locality.
>
> command:
> %echo Z > /proc/sys/vm/numa_zonelist_order
>
> Will rebuild zonelist in following order(new style, ZONE order)
>
> Node(0)'s NORMAL -> Node(1)'s NORMAL -> Node(0)'s DMA.
>
> means put more priority on zone_type.
>
> And you can specify this option as boot param.
>
> Because autoconfig function does nothing. Default is "Node" order.
>
> Tested on ia64 2-Node NUMA. works well.
>
> Signed-Off-By: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

sysctl documentation could use a bit of cleanup [spelling, inconsistent
statements re: default ordering], but this can be addressed in a
separate patch. Code looks/tested OK.

Acked-by: Lee.Schermerhorn <lee.schermerhorn@hp.com>
>
> ---
> Documentation/kernel-parameters.txt | 10 +
> Documentation/sysctl/vm.txt | 32 ++++++
> include/linux/mmzone.h | 5
> kernel/sysctl.c | 9 +
> mm/page_alloc.c | 185 ++++++++++++++++++++++++++++++++----
> 5 files changed, 225 insertions(+), 16 deletions(-)
>
> Index: linux-2.6.21-rc7-mm2/kernel/sysctl.c
> ===================================================================
> --- linux-2.6.21-rc7-mm2.orig/kernel/sysctl.c
> +++ linux-2.6.21-rc7-mm2/kernel/sysctl.c
> @@ -893,6 +893,15 @@ static ctl_table vm_table[] = {
> .extra1 = &zero,
> .extra2 = &one_hundred,
> },
> + {
> + .ctl_name = CTL_UNNUMBERED,
> + .procname = "numa_zonelist_order",
> + .data = &numa_zonelist_order,
> + .maxlen = NUMA_ZONELIST_ORDER_LEN,
> + .mode = 0644,
> + .proc_handler = &numa_zonelist_order_handler,
> + .strategy = &sysctl_string,
> + },
> #endif
> #if defined(CONFIG_X86_32) || \
> (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
> Index: linux-2.6.21-rc7-mm2/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.21-rc7-mm2.orig/mm/page_alloc.c
> +++ linux-2.6.21-rc7-mm2/mm/page_alloc.c
> @@ -2024,7 +2024,8 @@ void show_free_areas(void)
> * Add all populated zones of a node to the zonelist.
> */
> static int __meminit build_zonelists_node(pg_data_t *pgdat,
> - struct zonelist *zonelist, int nr_zones, enum zone_type zone_type)
> + struct zonelist *zonelist, int nr_zones,
> + enum zone_type zone_type)
> {
> struct zone *zone;
>
> @@ -2045,7 +2046,7 @@ 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
> @@ -2060,7 +2061,7 @@ 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;
> @@ -2106,13 +2107,124 @@ static int __meminit find_next_best_node
> return best_node;
> }
>
> -static void __meminit build_zonelists(pg_data_t *pgdat)
> +/*
> + * numa_zonelist_order:
> + * 0 = automatic detection of better ordering.
> + * 1 = order by ([node] distance, -zonetype)
> + * 2 = order by (-zonetype, [node] distance)
> + */
> +#define ZONELIST_ORDER_AUTO 0
> +#define ZONELIST_ORDER_NODE 1
> +#define ZONELIST_ORDER_ZONE 2
> +static int zonelist_order = 0;
> +
> +/*
> + * command line option "numa_zonelist_order"
> + * = "[dD]efault | "0" - default, automatic configuration.
> + * = "[nN]ode"|"1" - order by node locality,
> + * then zone within node.
> + * = "[zZ]one"|"2" - order by zone, then by locality within zone
> + */
> +char numa_zonelist_order[NUMA_ZONELIST_ORDER_LEN] = "default";
> +
> +static int __parse_numa_zonelist_order(char *s)
> +{
> + if (*s == 'd' || *s == 'D' || *s == '0') {
> + strncpy(numa_zonelist_order, "default",
> + NUMA_ZONELIST_ORDER_LEN);
> + zonelist_order = ZONELIST_ORDER_AUTO;
> + } else if (*s == 'n' || *s == 'N' || *s == '1') {
> + strncpy(numa_zonelist_order, "node",
> + NUMA_ZONELIST_ORDER_LEN);
> + zonelist_order = ZONELIST_ORDER_NODE;
> + } else if (*s == 'z' || *s == 'Z' || *s == '2') {
> + strncpy(numa_zonelist_order, "zone",
> + NUMA_ZONELIST_ORDER_LEN);
> + zonelist_order = ZONELIST_ORDER_ZONE;
> + } else {
> + printk(KERN_WARNING
> + "Ignoring invalid numa_zonelist_order value: "
> + "%s\n", s);
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +static __init int setup_numa_zonelist_order(char *s)
> +{
> + if (s)
> + return __parse_numa_zonelist_order(s);
> + return 0;
> +}
> +early_param("numa_zonelist_order", setup_numa_zonelist_order);
> +
> +/*
> + * Build zonelists ordered by node and zones within node.
> + * This results in maximum locality--normal zone overflows into local
> + * DMA zone, if any--but risks exhausting DMA zone.
> + */
> +static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
> {
> - int j, node, local_node;
> enum zone_type i;
> - int prev_node, load;
> + int j;
> + struct zonelist *zonelist;
> +
> + for (i = 0; i < MAX_NR_ZONES; i++) {
> + zonelist = pgdat->node_zonelists + i;
> + for (j = 0; zonelist->zones[j] != NULL; j++);
> +
> + j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
> + zonelist->zones[j] = NULL;
> + }
> +}
> +
> +/*
> + * Build zonelists ordered by zone and nodes within zones.
> + * This results in conserving DMA zone[s] until all Normal memory is
> + * exhausted, but results in overflowing to remote node while memory
> + * may still exist in local DMA zone.
> + */
> +static int node_order[MAX_NUMNODES];
> +
> +static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
> +{
> + enum zone_type i;
> + int pos, j, node;
> + int zone_type; /* needs to be signed */
> + struct zone *z;
> struct zonelist *zonelist;
> +
> + 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 < nr_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;
> + }
> +}
> +
> +static int estimate_zonelist_order(void)
> +{
> + /* dummy, just select node order. */
> + return ZONELIST_ORDER_NODE;
> +}
> +
> +
> +
> +static void build_zonelists(pg_data_t *pgdat)
> +{
> + int j, node, load;
> + enum zone_type i;
> nodemask_t used_mask;
> + int local_node, prev_node;
> + struct zonelist *zonelist;
> + int ordering;
>
> /* initialize zonelists */
> for (i = 0; i < MAX_NR_ZONES; i++) {
> @@ -2120,11 +2232,18 @@ static void __meminit build_zonelists(pg
> zonelist->zones[0] = NULL;
> }
>
> + ordering = zonelist_order;
> + if (ordering == ZONELIST_ORDER_AUTO)
> + ordering = estimate_zonelist_order();
> /* NUMA-aware ordering of nodes */
> local_node = pgdat->node_id;
> load = num_online_nodes();
> prev_node = local_node;
> nodes_clear(used_mask);
> +
> + memset(node_order, 0, sizeof(node_order));
> + j = 0;
> +
> while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
> int distance = node_distance(local_node, node);
>
> @@ -2140,18 +2259,20 @@ static void __meminit build_zonelists(pg
> * So adding penalty to the first node in same
> * distance group to make it round-robin.
> */
> -
> if (distance != node_distance(local_node, prev_node))
> - node_load[node] += load;
> + node_load[node] = load;
> +
> prev_node = node;
> load--;
> - for (i = 0; i < MAX_NR_ZONES; i++) {
> - zonelist = pgdat->node_zonelists + i;
> - for (j = 0; zonelist->zones[j] != NULL; j++);
> + if (ordering == ZONELIST_ORDER_NODE) /* default */
> + build_zonelists_in_node_order(pgdat, node);
> + else
> + node_order[j++] = node; /* remember order */
> + }
>
> - j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
> - zonelist->zones[j] = NULL;
> - }
> + if (ordering == ZONELIST_ORDER_ZONE) {
> + /* calculate node order -- i.e., DMA last! */
> + build_zonelists_in_zone_order(pgdat, j);
> }
> }
>
> @@ -2173,6 +2294,37 @@ static void __meminit build_zonelist_cac
> }
> }
>
> +/*
> + * sysctl handler for numa_zonelist_order
> + */
> +int numa_zonelist_order_handler(ctl_table *table, int write,
> + struct file *file, void __user *buffer, size_t *length,
> + loff_t *ppos)
> +{
> + char saved_string[NUMA_ZONELIST_ORDER_LEN];
> + int ret;
> +
> + if (write)
> + strncpy(saved_string, (char*)table->data,
> + NUMA_ZONELIST_ORDER_LEN);
> + ret = proc_dostring(table, write, file, buffer, length, ppos);
> + if (ret)
> + return ret;
> + if (write) {
> + int oldval = zonelist_order;
> + if (__parse_numa_zonelist_order((char*)table->data)) {
> + /*
> + * bogus value. restore saved string
> + */
> + strncpy((char*)table->data, saved_string,
> + NUMA_ZONELIST_ORDER_LEN);
> + zonelist_order = oldval;
> + } else if (oldval != zonelist_order)
> + build_all_zonelists();
> + }
> + return 0;
> +}
> +
> #else /* CONFIG_NUMA */
>
> static void __meminit build_zonelists(pg_data_t *pgdat)
> @@ -2222,7 +2374,7 @@ 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;
>
> @@ -2233,12 +2385,13 @@ 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-mm2/include/linux/mmzone.h
> ===================================================================
> --- linux-2.6.21-rc7-mm2.orig/include/linux/mmzone.h
> +++ linux-2.6.21-rc7-mm2/include/linux/mmzone.h
> @@ -608,6 +608,11 @@ 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 numa_zonelist_order_handler(struct ctl_table *, int,
> + struct file *, void __user *, size_t *, loff_t *);
> +extern char numa_zonelist_order[];
> +#define NUMA_ZONELIST_ORDER_LEN 16 /* string buffer size */
> +
> #include <linux/topology.h>
> /* Returns the number of the current Node. */
> #ifndef numa_node_id
> Index: linux-2.6.21-rc7-mm2/Documentation/kernel-parameters.txt
> ===================================================================
> --- linux-2.6.21-rc7-mm2.orig/Documentation/kernel-parameters.txt
> +++ linux-2.6.21-rc7-mm2/Documentation/kernel-parameters.txt
> @@ -1500,6 +1500,16 @@ and is between 256 and 4096 characters.
> Format: <reboot_mode>[,<reboot_mode2>[,...]]
> See arch/*/kernel/reboot.c or arch/*/kernel/process.c
>
> + numa_zonelist_order [KNL,BOOT]
> + Select memory allocation zonelist order for NUMA
> + platform. Default is automatic configuration.
> + "Node order" orders the zonelists by node [locality],
> + then zones within nodes. "Zone order" orders the
> + zonelists by zone,then nodes within the zone.
> + This moves DMA zone, if any, to the end of the
> + allocation lists.
> + See also Documentation/sysctl/vm.txt
> +
> reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
>
> reservetop= [X86-32]
> Index: linux-2.6.21-rc7-mm2/Documentation/sysctl/vm.txt
> ===================================================================
> --- linux-2.6.21-rc7-mm2.orig/Documentation/sysctl/vm.txt
> +++ linux-2.6.21-rc7-mm2/Documentation/sysctl/vm.txt
> @@ -34,6 +34,7 @@ Currently, these files are in /proc/sys/
> - swap_prefetch
> - readahead_ratio
> - readahead_hit_rate
> +- numa_zonelist_order
>
> ==============================================================
>
> @@ -275,3 +276,34 @@ Possible values can be:
> The larger value, the more capabilities, with more possible overheads.
>
> The default value is 1.
> +
> +=============================================================
> +
> +numa_zonelist_order
> +
> +This sysctl is only for NUMA.
> +
> +numa_zonelist_order selects the order of the memory allocation zonelists.
> +The default order [a.k.a. "node order"] orders the zonelists by node, the
then
> +by zone within each node. The default is automatic configuration.
> +Specify "[Dd]fault" or "0" to request automatic configuration.
"[Dd]efault" but maybe should be "[Aa]uto" based on Kame's
rework and to avoid confusion w/rt node order being default? ...
> +
> + For example, assume 2 Node NUMA. The "Node order" kernel memory allocation
> +order on Node(0) will be:
> +
> + Node(0)NORMAL -> Node(0)DMA -> Node(1)NORMAL -> Node(1)DMA(if any)
> +
> +Thus, allocations that request Node(0) NORMAL may overflow onto Node(0)DMA
> +first. This provides maximum locality, but risks exhausting all of DMA
> +memory while NORMAL memory exists elsewhere on the system. This can result
> +in OOM-KILL in ZONE_DMA. Secify "[Zz]one" or "1" to request zone order.
> +
> +If numa_zonelist_order is set to "node" order, the kernel memory allocation
> +order on Node(0) becomes:
> +
> + Node(0)NORMAL -> Node(1)NORMAL -> Node(0)DMA -> Node(1)DMA(if any)
> +
> +In this mode, DMA memory will be used in place of NORMAL memory, only when
> +all NORMAL zones are exhausted. Specify "[Nn]ode" or "2" for node order.
> +
> +The default value is 0.
>

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