[Devel] [PATCH rh7] mm: memcontrol: add memory.numa_migrate file
Vladimir Davydov
vdavydov at virtuozzo.com
Thu Aug 18 05:44:51 PDT 2016
The new file is supposed to be used for migrating pages accounted to a
memory cgroup to a particular set of numa nodes. The reason to add it is
that currently there's no API for migrating unmapped file pages used for
storing page cache (neither migrate_pages syscall nor cpuset subsys
doesn't provide this functionality).
The file is added to the memory cgroup and has the following format:
NODELIST[ MAX_SCAN]
where NODELIST is a comma-separated list of ranges N1-N2 specifying the set
of nodes to migrate pages of this cgroup to, and the optional MAX_SCAN
imposes a limit on the number of pages that can be migrated in one go.
The call may be interrupted by a signal, in which case -EINTR is returned.
https://jira.sw.ru/browse/PSBM-50875
Signed-off-by: Vladimir Davydov <vdavydov at virtuozzo.com>
Cc: Andrey Ryabinin <aryabinin at virtuozzo.com>
Cc: Igor Redko <redkoi at virtuozzo.com>
Cc: Konstantin Neumoin <kneumoin at virtuozzo.com>
---
mm/memcontrol.c | 223 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 223 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e3a16b99ccc6..8c6c4fb9c153 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -54,6 +54,7 @@
#include <linux/cpu.h>
#include <linux/oom.h>
#include <linux/virtinfo.h>
+#include <linux/migrate.h>
#include "internal.h"
#include <net/sock.h>
#include <net/ip.h>
@@ -5697,6 +5698,223 @@ static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft,
seq_putc(m, '\n');
return 0;
}
+
+/*
+ * memcg_numa_migrate_new_page() private argument. @target_nodes specifies the
+ * set of nodes to allocate pages from. @current_node is the current preferable
+ * node, it gets rotated after each allocation.
+ */
+struct memcg_numa_migrate_struct {
+ nodemask_t *target_nodes;
+ int current_node;
+};
+
+/*
+ * Used as an argument for migrate_pages(). Allocated pages are spread evenly
+ * among destination nodes.
+ */
+static struct page *memcg_numa_migrate_new_page(struct page *page,
+ unsigned long private, int **result)
+{
+ struct memcg_numa_migrate_struct *ms = (void *)private;
+ gfp_t gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_NORETRY | __GFP_NOWARN;
+
+ ms->current_node = next_node(ms->current_node, *ms->target_nodes);
+ if (ms->current_node >= MAX_NUMNODES) {
+ ms->current_node = first_node(*ms->target_nodes);
+ BUG_ON(ms->current_node >= MAX_NUMNODES);
+ }
+
+ return __alloc_pages_nodemask(gfp_mask, 0,
+ node_zonelist(ms->current_node, gfp_mask),
+ ms->target_nodes);
+}
+
+/*
+ * Isolate at most @nr_to_scan pages from @lruvec for further migration and
+ * store them in @dst. Returns the number of pages scanned. Return value of 0
+ * means that @lruved is empty.
+ */
+static long memcg_numa_isolate_pages(struct lruvec *lruvec, enum lru_list lru,
+ long nr_to_scan, struct list_head *dst)
+{
+ struct list_head *src = &lruvec->lists[lru];
+ struct zone *zone = lruvec_zone(lruvec);
+ long scanned = 0, taken = 0;
+
+ spin_lock_irq(&zone->lru_lock);
+ while (!list_empty(src) && scanned < nr_to_scan && taken < nr_to_scan) {
+ struct page *page = list_last_entry(src, struct page, lru);
+ int nr_pages;
+
+ VM_BUG_ON_PAGE(!PageLRU(page), page);
+
+ scanned++;
+
+ switch (__isolate_lru_page(page, ISOLATE_ASYNC_MIGRATE)) {
+ case 0:
+ nr_pages = hpage_nr_pages(page);
+ mem_cgroup_update_lru_size(lruvec, lru, -nr_pages);
+ list_move(&page->lru, dst);
+ taken += nr_pages;
+ break;
+
+ case -EBUSY:
+ list_move(&page->lru, src);
+ continue;
+
+ default:
+ BUG();
+ }
+ }
+ __mod_zone_page_state(zone, NR_LRU_BASE + lru, -taken);
+ __mod_zone_page_state(zone, NR_ISOLATED_ANON + is_file_lru(lru), taken);
+ spin_unlock_irq(&zone->lru_lock);
+
+ return scanned;
+}
+
+static long __memcg_numa_migrate_pages(struct lruvec *lruvec, enum lru_list lru,
+ nodemask_t *target_nodes, long nr_to_scan)
+{
+ struct memcg_numa_migrate_struct ms = {
+ .target_nodes = target_nodes,
+ .current_node = -1,
+ };
+ LIST_HEAD(pages);
+ long total_scanned = 0;
+
+ /*
+ * If no limit on the maximal number of migrated pages is specified,
+ * assume the caller wants to migrate them all.
+ */
+ if (nr_to_scan < 0)
+ nr_to_scan = mem_cgroup_get_lru_size(lruvec, lru);
+
+ while (total_scanned < nr_to_scan) {
+ int ret;
+ long scanned;
+
+ scanned = memcg_numa_isolate_pages(lruvec, lru,
+ SWAP_CLUSTER_MAX, &pages);
+ if (!scanned)
+ break;
+
+ ret = migrate_pages(&pages, memcg_numa_migrate_new_page,
+ (unsigned long)&ms, MIGRATE_ASYNC,
+ MR_SYSCALL);
+ putback_lru_pages(&pages);
+ if (ret < 0)
+ return ret;
+
+ if (signal_pending(current))
+ return -EINTR;
+
+ total_scanned += scanned;
+ }
+
+ return total_scanned;
+}
+
+/*
+ * Migrate at most @nr_to_scan pages accounted to @memcg to @target_nodes.
+ * Pages are spreaded evenly among destination nodes. If @nr_to_scan is <= 0,
+ * then the function will attempt to migrate all pages accounted to @memcg.
+ */
+static int memcg_numa_migrate_pages(struct mem_cgroup *memcg,
+ nodemask_t *target_nodes, long nr_to_scan)
+{
+ struct mem_cgroup *mi;
+ long total_scanned = 0;
+
+again:
+ for_each_mem_cgroup_tree(mi, memcg) {
+ struct zone *zone;
+
+ for_each_populated_zone(zone) {
+ struct lruvec *lruvec;
+ enum lru_list lru;
+ long scanned;
+
+ if (node_isset(zone_to_nid(zone), *target_nodes))
+ continue;
+
+ lruvec = mem_cgroup_zone_lruvec(zone, mi);
+ /*
+ * For the sake of simplicity, do not attempt to migrate
+ * unevictable pages. It should be fine as long as there
+ * aren't too many of them, which is usually true.
+ */
+ for_each_evictable_lru(lru) {
+ scanned = __memcg_numa_migrate_pages(lruvec,
+ lru, target_nodes,
+ nr_to_scan > 0 ?
+ SWAP_CLUSTER_MAX : -1);
+ if (scanned < 0) {
+ mem_cgroup_iter_break(memcg, mi);
+ return scanned;
+ }
+ total_scanned += scanned;
+ }
+ }
+ }
+
+ if (nr_to_scan > 0 && total_scanned < nr_to_scan)
+ goto again;
+
+ return 0;
+}
+
+/*
+ * The format of memory.numa_migrate is
+ *
+ * NODELIST[ MAX_SCAN]
+ *
+ * where NODELIST is a comma-separated list of ranges N1-N2 specifying the set
+ * of nodes to migrate pages of this cgroup to, and the optional MAX_SCAN
+ * imposes a limit on the number of pages that can be migrated in one go.
+ *
+ * The call may be interrupted by a signal, in which case -EINTR is returned.
+ */
+static int memcg_numa_migrate_write(struct cgroup *cont,
+ struct cftype *cft, const char *buf)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+ NODEMASK_ALLOC(nodemask_t, target_nodes, GFP_KERNEL);
+ const char *nodes_str = buf, *nr_str;
+ long nr_to_scan = -1;
+ int ret = -ENOMEM;
+
+ if (!target_nodes)
+ goto out;
+
+ nr_str = strchr(buf, ' ');
+ if (nr_str) {
+ nodes_str = kstrndup(buf, nr_str - buf, GFP_KERNEL);
+ if (!nodes_str)
+ goto out;
+ nr_str += 1;
+ }
+
+ ret = nodelist_parse(nodes_str, *target_nodes);
+ if (ret)
+ goto out;
+
+ ret = -EINVAL;
+ if (!nodes_subset(*target_nodes, node_states[N_MEMORY]))
+ goto out;
+
+ if (nr_str && (kstrtol(nr_str, 10, &nr_to_scan) || nr_to_scan <= 0))
+ goto out;
+
+ ret = memcg_numa_migrate_pages(memcg, target_nodes, nr_to_scan);
+out:
+ if (nodes_str != buf)
+ kfree(nodes_str);
+ NODEMASK_FREE(target_nodes);
+ return ret;
+}
+
#endif /* CONFIG_NUMA */
static inline void mem_cgroup_lru_names_not_uptodate(void)
@@ -6355,6 +6573,11 @@ static struct cftype mem_cgroup_files[] = {
.name = "numa_stat",
.read_seq_string = memcg_numa_stat_show,
},
+ {
+ .name = "numa_migrate",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .write_string = memcg_numa_migrate_write,
+ },
#endif
#ifdef CONFIG_CLEANCACHE
{
--
2.1.4
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