unsigned long targets[MEM_CGROUP_NTARGETS];
};
+struct mem_cgroup_reclaim_iter {
+ /* css_id of the last scanned hierarchy member */
+ int position;
+ /* scan generation, increased every round-trip */
+ unsigned int generation;
+};
+
/*
* per-zone information in memory controller.
*/
struct list_head lists[NR_LRU_LISTS];
unsigned long count[NR_LRU_LISTS];
+ struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
+
struct zone_reclaim_stat reclaim_stat;
struct rb_node tree_node; /* RB tree node */
unsigned long long usage_in_excess;/* Set to the value by which */
* per zone LRU lists.
*/
struct mem_cgroup_lru_info info;
- /*
- * While reclaiming in a hierarchy, we cache the last child we
- * reclaimed from.
- */
- int last_scanned_child;
int last_scanned_node;
#if MAX_NUMNODES > 1
nodemask_t scan_nodes;
#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
-#define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2
-#define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
static void mem_cgroup_get(struct mem_cgroup *memcg);
static void mem_cgroup_put(struct mem_cgroup *memcg);
return memcg;
}
-static struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
- struct mem_cgroup *prev,
- bool reclaim)
+/**
+ * mem_cgroup_iter - iterate over memory cgroup hierarchy
+ * @root: hierarchy root
+ * @prev: previously returned memcg, NULL on first invocation
+ * @reclaim: cookie for shared reclaim walks, NULL for full walks
+ *
+ * Returns references to children of the hierarchy below @root, or
+ * @root itself, or %NULL after a full round-trip.
+ *
+ * Caller must pass the return value in @prev on subsequent
+ * invocations for reference counting, or use mem_cgroup_iter_break()
+ * to cancel a hierarchy walk before the round-trip is complete.
+ *
+ * Reclaimers can specify a zone and a priority level in @reclaim to
+ * divide up the memcgs in the hierarchy among all concurrent
+ * reclaimers operating on the same zone and priority.
+ */
+struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
+ struct mem_cgroup *prev,
+ struct mem_cgroup_reclaim_cookie *reclaim)
{
struct mem_cgroup *memcg = NULL;
int id = 0;
+ if (mem_cgroup_disabled())
+ return NULL;
+
if (!root)
root = root_mem_cgroup;
}
while (!memcg) {
+ struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
struct cgroup_subsys_state *css;
- if (reclaim)
- id = root->last_scanned_child;
+ if (reclaim) {
+ int nid = zone_to_nid(reclaim->zone);
+ int zid = zone_idx(reclaim->zone);
+ struct mem_cgroup_per_zone *mz;
+
+ mz = mem_cgroup_zoneinfo(root, nid, zid);
+ iter = &mz->reclaim_iter[reclaim->priority];
+ if (prev && reclaim->generation != iter->generation)
+ return NULL;
+ id = iter->position;
+ }
rcu_read_lock();
css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
id = 0;
rcu_read_unlock();
- if (reclaim)
- root->last_scanned_child = id;
+ if (reclaim) {
+ iter->position = id;
+ if (!css)
+ iter->generation++;
+ else if (!prev && memcg)
+ reclaim->generation = iter->generation;
+ }
if (prev && !css)
return NULL;
return memcg;
}
-static void mem_cgroup_iter_break(struct mem_cgroup *root,
- struct mem_cgroup *prev)
+/**
+ * mem_cgroup_iter_break - abort a hierarchy walk prematurely
+ * @root: hierarchy root
+ * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
+ */
+void mem_cgroup_iter_break(struct mem_cgroup *root,
+ struct mem_cgroup *prev)
{
if (!root)
root = root_mem_cgroup;
* be used for reference counting.
*/
#define for_each_mem_cgroup_tree(iter, root) \
- for (iter = mem_cgroup_iter(root, NULL, false); \
+ for (iter = mem_cgroup_iter(root, NULL, NULL); \
iter != NULL; \
- iter = mem_cgroup_iter(root, iter, false))
+ iter = mem_cgroup_iter(root, iter, NULL))
#define for_each_mem_cgroup(iter) \
- for (iter = mem_cgroup_iter(NULL, NULL, false); \
+ for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
iter != NULL; \
- iter = mem_cgroup_iter(NULL, iter, false))
+ iter = mem_cgroup_iter(NULL, iter, NULL))
static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
{
mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
/* huge page split is done under lru_lock. so, we have no races. */
MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
- if (mem_cgroup_is_root(pc->mem_cgroup))
- return;
VM_BUG_ON(list_empty(&pc->lru));
list_del_init(&pc->lru);
}
return;
pc = lookup_page_cgroup(page);
- /* unused or root page is not rotated. */
+ /* unused page is not rotated. */
if (!PageCgroupUsed(pc))
return;
/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
smp_rmb();
- if (mem_cgroup_is_root(pc->mem_cgroup))
- return;
mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
list_move_tail(&pc->lru, &mz->lists[lru]);
}
return;
pc = lookup_page_cgroup(page);
- /* unused or root page is not rotated. */
+ /* unused page is not rotated. */
if (!PageCgroupUsed(pc))
return;
/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
smp_rmb();
- if (mem_cgroup_is_root(pc->mem_cgroup))
- return;
mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
list_move(&pc->lru, &mz->lists[lru]);
}
/* huge page split is done under lru_lock. so, we have no races. */
MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
SetPageCgroupAcctLRU(pc);
- if (mem_cgroup_is_root(pc->mem_cgroup))
- return;
list_add(&pc->lru, &mz->lists[lru]);
}
return min(limit, memsw);
}
+static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
+ gfp_t gfp_mask,
+ unsigned long flags)
+{
+ unsigned long total = 0;
+ bool noswap = false;
+ int loop;
+
+ if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
+ noswap = true;
+ if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
+ noswap = true;
+
+ for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
+ if (loop)
+ drain_all_stock_async(memcg);
+ total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
+ /*
+ * Allow limit shrinkers, which are triggered directly
+ * by userspace, to catch signals and stop reclaim
+ * after minimal progress, regardless of the margin.
+ */
+ if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
+ break;
+ if (mem_cgroup_margin(memcg))
+ break;
+ /*
+ * If nothing was reclaimed after two attempts, there
+ * may be no reclaimable pages in this hierarchy.
+ */
+ if (loop && !total)
+ break;
+ }
+ return total;
+}
+
/**
* test_mem_cgroup_node_reclaimable
* @mem: the target memcg
}
#endif
-/*
- * Scan the hierarchy if needed to reclaim memory. We remember the last child
- * we reclaimed from, so that we don't end up penalizing one child extensively
- * based on its position in the children list.
- *
- * root_memcg is the original ancestor that we've been reclaim from.
- *
- * We give up and return to the caller when we visit root_memcg twice.
- * (other groups can be removed while we're walking....)
- *
- * If shrink==true, for avoiding to free too much, this returns immedieately.
- */
-static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_memcg,
- struct zone *zone,
- gfp_t gfp_mask,
- unsigned long reclaim_options,
- unsigned long *total_scanned)
+static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
+ struct zone *zone,
+ gfp_t gfp_mask,
+ unsigned long *total_scanned)
{
struct mem_cgroup *victim = NULL;
- int ret, total = 0;
+ int total = 0;
int loop = 0;
- bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
- bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
- bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
unsigned long excess;
unsigned long nr_scanned;
+ struct mem_cgroup_reclaim_cookie reclaim = {
+ .zone = zone,
+ .priority = 0,
+ };
excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
- /* If memsw_is_minimum==1, swap-out is of-no-use. */
- if (!check_soft && !shrink && root_memcg->memsw_is_minimum)
- noswap = true;
-
while (1) {
- victim = mem_cgroup_iter(root_memcg, victim, true);
+ victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
if (!victim) {
loop++;
- /*
- * We are not draining per cpu cached charges during
- * soft limit reclaim because global reclaim doesn't
- * care about charges. It tries to free some memory and
- * charges will not give any.
- */
- if (!check_soft && loop >= 1)
- drain_all_stock_async(root_memcg);
if (loop >= 2) {
/*
* If we have not been able to reclaim
* anything, it might because there are
* no reclaimable pages under this hierarchy
*/
- if (!check_soft || !total)
+ if (!total)
break;
/*
* We want to do more targeted reclaim.
}
continue;
}
- if (!mem_cgroup_reclaimable(victim, noswap)) {
- /* this cgroup's local usage == 0 */
+ if (!mem_cgroup_reclaimable(victim, false))
continue;
- }
- /* we use swappiness of local cgroup */
- if (check_soft) {
- ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
- noswap, zone, &nr_scanned);
- *total_scanned += nr_scanned;
- } else
- ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
- noswap);
- total += ret;
- /*
- * At shrinking usage, we can't check we should stop here or
- * reclaim more. It's depends on callers. last_scanned_child
- * will work enough for keeping fairness under tree.
- */
- if (shrink)
- break;
- if (check_soft) {
- if (!res_counter_soft_limit_excess(&root_memcg->res))
- break;
- } else if (mem_cgroup_margin(root_memcg))
+ total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
+ zone, &nr_scanned);
+ *total_scanned += nr_scanned;
+ if (!res_counter_soft_limit_excess(&root_memcg->res))
break;
}
mem_cgroup_iter_break(root_memcg, victim);
if (!(gfp_mask & __GFP_WAIT))
return CHARGE_WOULDBLOCK;
- ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
- gfp_mask, flags, NULL);
+ ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
return CHARGE_RETRY;
/*
if (!ret)
break;
- mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
- MEM_CGROUP_RECLAIM_SHRINK,
- NULL);
+ mem_cgroup_reclaim(memcg, GFP_KERNEL,
+ MEM_CGROUP_RECLAIM_SHRINK);
curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
/* Usage is reduced ? */
if (curusage >= oldusage)
if (!ret)
break;
- mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
- MEM_CGROUP_RECLAIM_NOSWAP |
- MEM_CGROUP_RECLAIM_SHRINK,
- NULL);
+ mem_cgroup_reclaim(memcg, GFP_KERNEL,
+ MEM_CGROUP_RECLAIM_NOSWAP |
+ MEM_CGROUP_RECLAIM_SHRINK);
curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
/* Usage is reduced ? */
if (curusage >= oldusage)
break;
nr_scanned = 0;
- reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
- gfp_mask,
- MEM_CGROUP_RECLAIM_SOFT,
- &nr_scanned);
+ reclaimed = mem_cgroup_soft_reclaim(mz->mem, zone,
+ gfp_mask, &nr_scanned);
nr_reclaimed += reclaimed;
*total_scanned += nr_scanned;
spin_lock(&mctz->lock);
res_counter_init(&memcg->res, NULL);
res_counter_init(&memcg->memsw, NULL);
}
- memcg->last_scanned_child = 0;
memcg->last_scanned_node = MAX_NUMNODES;
INIT_LIST_HEAD(&memcg->oom_notify);
projects / linux-beck.git / blobdiff