#ifdef CONFIG_MEMCG
static int shrinker_nr_max;
+/* The shrinker_info is expanded in a batch of BITS_PER_LONG */
static inline int shrinker_map_size(int nr_items)
{
return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long));
}
-static void free_shrinker_map_rcu(struct rcu_head *head)
+static inline int shrinker_defer_size(int nr_items)
{
- kvfree(container_of(head, struct memcg_shrinker_map, rcu));
+ return (round_up(nr_items, BITS_PER_LONG) * sizeof(atomic_long_t));
}
-static int expand_one_shrinker_map(struct mem_cgroup *memcg,
- int size, int old_size)
+static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
+ int nid)
{
- struct memcg_shrinker_map *new, *old;
+ return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
+ lockdep_is_held(&shrinker_rwsem));
+}
+
+static int expand_one_shrinker_info(struct mem_cgroup *memcg,
+ int map_size, int defer_size,
+ int old_map_size, int old_defer_size)
+{
+ struct shrinker_info *new, *old;
struct mem_cgroup_per_node *pn;
int nid;
+ int size = map_size + defer_size;
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
- old = rcu_dereference_protected(pn->shrinker_map, true);
+ old = shrinker_info_protected(memcg, nid);
/* Not yet online memcg */
if (!old)
return 0;
if (!new)
return -ENOMEM;
- /* Set all old bits, clear all new bits */
- memset(new->map, (int)0xff, old_size);
- memset((void *)new->map + old_size, 0, size - old_size);
+ new->nr_deferred = (atomic_long_t *)(new + 1);
+ new->map = (void *)new->nr_deferred + defer_size;
+
+ /* map: set all old bits, clear all new bits */
+ memset(new->map, (int)0xff, old_map_size);
+ memset((void *)new->map + old_map_size, 0, map_size - old_map_size);
+ /* nr_deferred: copy old values, clear all new values */
+ memcpy(new->nr_deferred, old->nr_deferred, old_defer_size);
+ memset((void *)new->nr_deferred + old_defer_size, 0,
+ defer_size - old_defer_size);
- rcu_assign_pointer(pn->shrinker_map, new);
- call_rcu(&old->rcu, free_shrinker_map_rcu);
+ rcu_assign_pointer(pn->shrinker_info, new);
+ kvfree_rcu(old, rcu);
}
return 0;
}
-void free_shrinker_maps(struct mem_cgroup *memcg)
+void free_shrinker_info(struct mem_cgroup *memcg)
{
struct mem_cgroup_per_node *pn;
- struct memcg_shrinker_map *map;
+ struct shrinker_info *info;
int nid;
- if (mem_cgroup_is_root(memcg))
- return;
-
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
- map = rcu_dereference_protected(pn->shrinker_map, true);
- kvfree(map);
- rcu_assign_pointer(pn->shrinker_map, NULL);
+ info = rcu_dereference_protected(pn->shrinker_info, true);
+ kvfree(info);
+ rcu_assign_pointer(pn->shrinker_info, NULL);
}
}
-int alloc_shrinker_maps(struct mem_cgroup *memcg)
+int alloc_shrinker_info(struct mem_cgroup *memcg)
{
- struct memcg_shrinker_map *map;
+ struct shrinker_info *info;
int nid, size, ret = 0;
-
- if (mem_cgroup_is_root(memcg))
- return 0;
+ int map_size, defer_size = 0;
down_write(&shrinker_rwsem);
- size = shrinker_map_size(shrinker_nr_max);
+ map_size = shrinker_map_size(shrinker_nr_max);
+ defer_size = shrinker_defer_size(shrinker_nr_max);
+ size = map_size + defer_size;
for_each_node(nid) {
- map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid);
- if (!map) {
- free_shrinker_maps(memcg);
+ info = kvzalloc_node(sizeof(*info) + size, GFP_KERNEL, nid);
+ if (!info) {
+ free_shrinker_info(memcg);
ret = -ENOMEM;
break;
}
- rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map);
+ info->nr_deferred = (atomic_long_t *)(info + 1);
+ info->map = (void *)info->nr_deferred + defer_size;
+ rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info);
}
up_write(&shrinker_rwsem);
return ret;
}
-static int expand_shrinker_maps(int new_id)
+static inline bool need_expand(int nr_max)
+{
+ return round_up(nr_max, BITS_PER_LONG) >
+ round_up(shrinker_nr_max, BITS_PER_LONG);
+}
+
+static int expand_shrinker_info(int new_id)
{
- int size, old_size, ret = 0;
+ int ret = 0;
int new_nr_max = new_id + 1;
+ int map_size, defer_size = 0;
+ int old_map_size, old_defer_size = 0;
struct mem_cgroup *memcg;
- size = shrinker_map_size(new_nr_max);
- old_size = shrinker_map_size(shrinker_nr_max);
- if (size <= old_size)
+ if (!need_expand(new_nr_max))
goto out;
if (!root_mem_cgroup)
lockdep_assert_held(&shrinker_rwsem);
+ map_size = shrinker_map_size(new_nr_max);
+ defer_size = shrinker_defer_size(new_nr_max);
+ old_map_size = shrinker_map_size(shrinker_nr_max);
+ old_defer_size = shrinker_defer_size(shrinker_nr_max);
+
memcg = mem_cgroup_iter(NULL, NULL, NULL);
do {
- if (mem_cgroup_is_root(memcg))
- continue;
- ret = expand_one_shrinker_map(memcg, size, old_size);
+ ret = expand_one_shrinker_info(memcg, map_size, defer_size,
+ old_map_size, old_defer_size);
if (ret) {
mem_cgroup_iter_break(NULL, memcg);
goto out;
void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
{
if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) {
- struct memcg_shrinker_map *map;
+ struct shrinker_info *info;
rcu_read_lock();
- map = rcu_dereference(memcg->nodeinfo[nid]->shrinker_map);
+ info = rcu_dereference(memcg->nodeinfo[nid]->shrinker_info);
/* Pairs with smp mb in shrink_slab() */
smp_mb__before_atomic();
- set_bit(shrinker_id, map->map);
+ set_bit(shrinker_id, info->map);
rcu_read_unlock();
}
}
-/*
- * We allow subsystems to populate their shrinker-related
- * LRU lists before register_shrinker_prepared() is called
- * for the shrinker, since we don't want to impose
- * restrictions on their internal registration order.
- * In this case shrink_slab_memcg() may find corresponding
- * bit is set in the shrinkers map.
- *
- * This value is used by the function to detect registering
- * shrinkers and to skip do_shrink_slab() calls for them.
- */
-#define SHRINKER_REGISTERING ((struct shrinker *)~0UL)
-
static DEFINE_IDR(shrinker_idr);
static int prealloc_memcg_shrinker(struct shrinker *shrinker)
{
int id, ret = -ENOMEM;
+ if (mem_cgroup_disabled())
+ return -ENOSYS;
+
down_write(&shrinker_rwsem);
/* This may call shrinker, so it must use down_read_trylock() */
- id = idr_alloc(&shrinker_idr, SHRINKER_REGISTERING, 0, 0, GFP_KERNEL);
+ id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL);
if (id < 0)
goto unlock;
if (id >= shrinker_nr_max) {
- if (expand_shrinker_maps(id)) {
+ if (expand_shrinker_info(id)) {
idr_remove(&shrinker_idr, id);
goto unlock;
}
BUG_ON(id < 0);
- down_write(&shrinker_rwsem);
+ lockdep_assert_held(&shrinker_rwsem);
+
idr_remove(&shrinker_idr, id);
- up_write(&shrinker_rwsem);
+}
+
+static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
+ struct mem_cgroup *memcg)
+{
+ struct shrinker_info *info;
+
+ info = shrinker_info_protected(memcg, nid);
+ return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0);
+}
+
+static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
+ struct mem_cgroup *memcg)
+{
+ struct shrinker_info *info;
+
+ info = shrinker_info_protected(memcg, nid);
+ return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
+}
+
+void reparent_shrinker_deferred(struct mem_cgroup *memcg)
+{
+ int i, nid;
+ long nr;
+ struct mem_cgroup *parent;
+ struct shrinker_info *child_info, *parent_info;
+
+ parent = parent_mem_cgroup(memcg);
+ if (!parent)
+ parent = root_mem_cgroup;
+
+ /* Prevent from concurrent shrinker_info expand */
+ down_read(&shrinker_rwsem);
+ for_each_node(nid) {
+ child_info = shrinker_info_protected(memcg, nid);
+ parent_info = shrinker_info_protected(parent, nid);
+ for (i = 0; i < shrinker_nr_max; i++) {
+ nr = atomic_long_read(&child_info->nr_deferred[i]);
+ atomic_long_add(nr, &parent_info->nr_deferred[i]);
+ }
+ }
+ up_read(&shrinker_rwsem);
}
static bool cgroup_reclaim(struct scan_control *sc)
#else
static int prealloc_memcg_shrinker(struct shrinker *shrinker)
{
- return 0;
+ return -ENOSYS;
}
static void unregister_memcg_shrinker(struct shrinker *shrinker)
{
}
+static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
+ struct mem_cgroup *memcg)
+{
+ return 0;
+}
+
+static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
+ struct mem_cgroup *memcg)
+{
+ return 0;
+}
+
static bool cgroup_reclaim(struct scan_control *sc)
{
return false;
}
#endif
+static long xchg_nr_deferred(struct shrinker *shrinker,
+ struct shrink_control *sc)
+{
+ int nid = sc->nid;
+
+ if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
+ nid = 0;
+
+ if (sc->memcg &&
+ (shrinker->flags & SHRINKER_MEMCG_AWARE))
+ return xchg_nr_deferred_memcg(nid, shrinker,
+ sc->memcg);
+
+ return atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
+}
+
+
+static long add_nr_deferred(long nr, struct shrinker *shrinker,
+ struct shrink_control *sc)
+{
+ int nid = sc->nid;
+
+ if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
+ nid = 0;
+
+ if (sc->memcg &&
+ (shrinker->flags & SHRINKER_MEMCG_AWARE))
+ return add_nr_deferred_memcg(nr, nid, shrinker,
+ sc->memcg);
+
+ return atomic_long_add_return(nr, &shrinker->nr_deferred[nid]);
+}
+
/*
* This misses isolated pages which are not accounted for to save counters.
* As the data only determines if reclaim or compaction continues, it is
*/
int prealloc_shrinker(struct shrinker *shrinker)
{
- unsigned int size = sizeof(*shrinker->nr_deferred);
+ unsigned int size;
+ int err;
+
+ if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
+ err = prealloc_memcg_shrinker(shrinker);
+ if (err != -ENOSYS)
+ return err;
+
+ shrinker->flags &= ~SHRINKER_MEMCG_AWARE;
+ }
+ size = sizeof(*shrinker->nr_deferred);
if (shrinker->flags & SHRINKER_NUMA_AWARE)
size *= nr_node_ids;
if (!shrinker->nr_deferred)
return -ENOMEM;
- if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
- if (prealloc_memcg_shrinker(shrinker))
- goto free_deferred;
- }
-
return 0;
-
-free_deferred:
- kfree(shrinker->nr_deferred);
- shrinker->nr_deferred = NULL;
- return -ENOMEM;
}
void free_prealloced_shrinker(struct shrinker *shrinker)
{
- if (!shrinker->nr_deferred)
- return;
-
- if (shrinker->flags & SHRINKER_MEMCG_AWARE)
+ if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
+ down_write(&shrinker_rwsem);
unregister_memcg_shrinker(shrinker);
+ up_write(&shrinker_rwsem);
+ return;
+ }
kfree(shrinker->nr_deferred);
shrinker->nr_deferred = NULL;
{
down_write(&shrinker_rwsem);
list_add_tail(&shrinker->list, &shrinker_list);
-#ifdef CONFIG_MEMCG
- if (shrinker->flags & SHRINKER_MEMCG_AWARE)
- idr_replace(&shrinker_idr, shrinker, shrinker->id);
-#endif
+ shrinker->flags |= SHRINKER_REGISTERED;
up_write(&shrinker_rwsem);
}
*/
void unregister_shrinker(struct shrinker *shrinker)
{
- if (!shrinker->nr_deferred)
+ if (!(shrinker->flags & SHRINKER_REGISTERED))
return;
- if (shrinker->flags & SHRINKER_MEMCG_AWARE)
- unregister_memcg_shrinker(shrinker);
+
down_write(&shrinker_rwsem);
list_del(&shrinker->list);
+ shrinker->flags &= ~SHRINKER_REGISTERED;
+ if (shrinker->flags & SHRINKER_MEMCG_AWARE)
+ unregister_memcg_shrinker(shrinker);
up_write(&shrinker_rwsem);
+
kfree(shrinker->nr_deferred);
shrinker->nr_deferred = NULL;
}
long freeable;
long nr;
long new_nr;
- int nid = shrinkctl->nid;
long batch_size = shrinker->batch ? shrinker->batch
: SHRINK_BATCH;
long scanned = 0, next_deferred;
- if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
- nid = 0;
-
freeable = shrinker->count_objects(shrinker, shrinkctl);
if (freeable == 0 || freeable == SHRINK_EMPTY)
return freeable;
* and zero it so that other concurrent shrinker invocations
* don't also do this scanning work.
*/
- nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
+ nr = xchg_nr_deferred(shrinker, shrinkctl);
- total_scan = nr;
if (shrinker->seeks) {
delta = freeable >> priority;
delta *= 4;
delta = freeable / 2;
}
+ total_scan = nr >> priority;
total_scan += delta;
- if (total_scan < 0) {
- pr_err("shrink_slab: %pS negative objects to delete nr=%ld\n",
- shrinker->scan_objects, total_scan);
- total_scan = freeable;
- next_deferred = nr;
- } else
- next_deferred = total_scan;
-
- /*
- * We need to avoid excessive windup on filesystem shrinkers
- * due to large numbers of GFP_NOFS allocations causing the
- * shrinkers to return -1 all the time. This results in a large
- * nr being built up so when a shrink that can do some work
- * comes along it empties the entire cache due to nr >>>
- * freeable. This is bad for sustaining a working set in
- * memory.
- *
- * Hence only allow the shrinker to scan the entire cache when
- * a large delta change is calculated directly.
- */
- if (delta < freeable / 4)
- total_scan = min(total_scan, freeable / 2);
-
- /*
- * Avoid risking looping forever due to too large nr value:
- * never try to free more than twice the estimate number of
- * freeable entries.
- */
- if (total_scan > freeable * 2)
- total_scan = freeable * 2;
+ total_scan = min(total_scan, (2 * freeable));
trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
freeable, delta, total_scan, priority);
cond_resched();
}
- if (next_deferred >= scanned)
- next_deferred -= scanned;
- else
- next_deferred = 0;
+ /*
+ * The deferred work is increased by any new work (delta) that wasn't
+ * done, decreased by old deferred work that was done now.
+ *
+ * And it is capped to two times of the freeable items.
+ */
+ next_deferred = max_t(long, (nr + delta - scanned), 0);
+ next_deferred = min(next_deferred, (2 * freeable));
+
/*
* move the unused scan count back into the shrinker in a
- * manner that handles concurrent updates. If we exhausted the
- * scan, there is no need to do an update.
+ * manner that handles concurrent updates.
*/
- if (next_deferred > 0)
- new_nr = atomic_long_add_return(next_deferred,
- &shrinker->nr_deferred[nid]);
- else
- new_nr = atomic_long_read(&shrinker->nr_deferred[nid]);
+ new_nr = add_nr_deferred(next_deferred, shrinker, shrinkctl);
trace_mm_shrink_slab_end(shrinker, shrinkctl->nid, freed, nr, new_nr, total_scan);
return freed;
static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
struct mem_cgroup *memcg, int priority)
{
- struct memcg_shrinker_map *map;
+ struct shrinker_info *info;
unsigned long ret, freed = 0;
int i;
if (!down_read_trylock(&shrinker_rwsem))
return 0;
- map = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_map,
- true);
- if (unlikely(!map))
+ info = shrinker_info_protected(memcg, nid);
+ if (unlikely(!info))
goto unlock;
- for_each_set_bit(i, map->map, shrinker_nr_max) {
+ for_each_set_bit(i, info->map, shrinker_nr_max) {
struct shrink_control sc = {
.gfp_mask = gfp_mask,
.nid = nid,
struct shrinker *shrinker;
shrinker = idr_find(&shrinker_idr, i);
- if (unlikely(!shrinker || shrinker == SHRINKER_REGISTERING)) {
+ if (unlikely(!shrinker || !(shrinker->flags & SHRINKER_REGISTERED))) {
if (!shrinker)
- clear_bit(i, map->map);
+ clear_bit(i, info->map);
continue;
}
ret = do_shrink_slab(&sc, shrinker, priority);
if (ret == SHRINK_EMPTY) {
- clear_bit(i, map->map);
+ clear_bit(i, info->map);
/*
* After the shrinker reported that it had no objects to
* free, but before we cleared the corresponding bit in
{
unsigned int alloc_order, reclaim_order;
unsigned int highest_zoneidx = MAX_NR_ZONES - 1;
- pg_data_t *pgdat = (pg_data_t*)p;
+ pg_data_t *pgdat = (pg_data_t *)p;
struct task_struct *tsk = current;
const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
projects / linux-2.6-microblaze.git / blobdiff