diff options
| -rw-r--r-- | include/linux/shrinker.h | 14 | ||||
| -rw-r--r-- | mm/vmscan.c | 241 |
2 files changed, 152 insertions, 103 deletions
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 76f520c4c39..8f80f243fed 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -19,6 +19,8 @@ struct shrink_control { /* shrink from these nodes */ nodemask_t nodes_to_scan; + /* current node being shrunk (for NUMA aware shrinkers) */ + int nid; }; #define SHRINK_STOP (~0UL) @@ -44,6 +46,8 @@ struct shrink_control { * due to potential deadlocks. If SHRINK_STOP is returned, then no further * attempts to call the @scan_objects will be made from the current reclaim * context. + * + * @flags determine the shrinker abilities, like numa awareness */ struct shrinker { int (*shrink)(struct shrinker *, struct shrink_control *sc); @@ -54,12 +58,18 @@ struct shrinker { int seeks; /* seeks to recreate an obj */ long batch; /* reclaim batch size, 0 = default */ + unsigned long flags; /* These are for internal use */ struct list_head list; - atomic_long_t nr_in_batch; /* objs pending delete */ + /* objs pending delete, per node */ + atomic_long_t *nr_deferred; }; #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */ -extern void register_shrinker(struct shrinker *); + +/* Flags */ +#define SHRINKER_NUMA_AWARE (1 << 0) + +extern int register_shrinker(struct shrinker *); extern void unregister_shrinker(struct shrinker *); #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index fe0d5c45844..799ebceeb4f 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -155,14 +155,31 @@ static unsigned long get_lru_size(struct lruvec *lruvec, enum lru_list lru) } /* - * Add a shrinker callback to be called from the vm + * Add a shrinker callback to be called from the vm. */ -void register_shrinker(struct shrinker *shrinker) +int register_shrinker(struct shrinker *shrinker) { - atomic_long_set(&shrinker->nr_in_batch, 0); + size_t size = sizeof(*shrinker->nr_deferred); + + /* + * If we only have one possible node in the system anyway, save + * ourselves the trouble and disable NUMA aware behavior. This way we + * will save memory and some small loop time later. + */ + if (nr_node_ids == 1) + shrinker->flags &= ~SHRINKER_NUMA_AWARE; + + if (shrinker->flags & SHRINKER_NUMA_AWARE) + size *= nr_node_ids; + + shrinker->nr_deferred = kzalloc(size, GFP_KERNEL); + if (!shrinker->nr_deferred) + return -ENOMEM; + down_write(&shrinker_rwsem); list_add_tail(&shrinker->list, &shrinker_list); up_write(&shrinker_rwsem); + return 0; } EXPORT_SYMBOL(register_shrinker); @@ -186,6 +203,118 @@ static inline int do_shrinker_shrink(struct shrinker *shrinker, } #define SHRINK_BATCH 128 + +static unsigned long +shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker, + unsigned long nr_pages_scanned, unsigned long lru_pages) +{ + unsigned long freed = 0; + unsigned long long delta; + long total_scan; + long max_pass; + long nr; + long new_nr; + int nid = shrinkctl->nid; + long batch_size = shrinker->batch ? shrinker->batch + : SHRINK_BATCH; + + if (shrinker->count_objects) + max_pass = shrinker->count_objects(shrinker, shrinkctl); + else + max_pass = do_shrinker_shrink(shrinker, shrinkctl, 0); + if (max_pass == 0) + return 0; + + /* + * copy the current shrinker scan count into a local variable + * 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); + + total_scan = nr; + delta = (4 * nr_pages_scanned) / shrinker->seeks; + delta *= max_pass; + do_div(delta, lru_pages + 1); + total_scan += delta; + if (total_scan < 0) { + printk(KERN_ERR + "shrink_slab: %pF negative objects to delete nr=%ld\n", + shrinker->shrink, total_scan); + total_scan = max_pass; + } + + /* + * 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 >>> + * max_pass. 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 < max_pass / 4) + total_scan = min(total_scan, max_pass / 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 > max_pass * 2) + total_scan = max_pass * 2; + + trace_mm_shrink_slab_start(shrinker, shrinkctl, nr, + nr_pages_scanned, lru_pages, + max_pass, delta, total_scan); + + while (total_scan >= batch_size) { + + if (shrinker->scan_objects) { + unsigned long ret; + shrinkctl->nr_to_scan = batch_size; + ret = shrinker->scan_objects(shrinker, shrinkctl); + + if (ret == SHRINK_STOP) + break; + freed += ret; + } else { + int nr_before; + long ret; + + nr_before = do_shrinker_shrink(shrinker, shrinkctl, 0); + ret = do_shrinker_shrink(shrinker, shrinkctl, + batch_size); + if (ret == -1) + break; + if (ret < nr_before) + freed += nr_before - ret; + } + + count_vm_events(SLABS_SCANNED, batch_size); + total_scan -= batch_size; + + cond_resched(); + } + + /* + * 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. + */ + if (total_scan > 0) + new_nr = atomic_long_add_return(total_scan, + &shrinker->nr_deferred[nid]); + else + new_nr = atomic_long_read(&shrinker->nr_deferred[nid]); + + trace_mm_shrink_slab_end(shrinker, freed, nr, new_nr); + return freed; +} + /* * Call the shrink functions to age shrinkable caches * @@ -227,108 +356,18 @@ unsigned long shrink_slab(struct shrink_control *shrinkctl, } list_for_each_entry(shrinker, &shrinker_list, list) { - unsigned long long delta; - long total_scan; - long max_pass; - long nr; - long new_nr; - long batch_size = shrinker->batch ? shrinker->batch - : SHRINK_BATCH; - - if (shrinker->count_objects) - max_pass = shrinker->count_objects(shrinker, shrinkctl); - else - max_pass = do_shrinker_shrink(shrinker, shrinkctl, 0); - if (max_pass == 0) - continue; - - /* - * copy the current shrinker scan count into a local variable - * and zero it so that other concurrent shrinker invocations - * don't also do this scanning work. - */ - nr = atomic_long_xchg(&shrinker->nr_in_batch, 0); - - total_scan = nr; - delta = (4 * nr_pages_scanned) / shrinker->seeks; - delta *= max_pass; - do_div(delta, lru_pages + 1); - total_scan += delta; - if (total_scan < 0) { - printk(KERN_ERR - "shrink_slab: %pF negative objects to delete nr=%ld\n", - shrinker->shrink, total_scan); - total_scan = max_pass; - } - - /* - * 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 >>> - * max_pass. 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 < max_pass / 4) - total_scan = min(total_scan, max_pass / 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 > max_pass * 2) - total_scan = max_pass * 2; - - trace_mm_shrink_slab_start(shrinker, shrinkctl, nr, - nr_pages_scanned, lru_pages, - max_pass, delta, total_scan); - - while (total_scan >= batch_size) { - - if (shrinker->scan_objects) { - unsigned long ret; - shrinkctl->nr_to_scan = batch_size; - ret = shrinker->scan_objects(shrinker, shrinkctl); + for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) { + if (!node_online(shrinkctl->nid)) + continue; - if (ret == SHRINK_STOP) - break; - freed += ret; - } else { - int nr_before; - long ret; - - nr_before = do_shrinker_shrink(shrinker, shrinkctl, 0); - ret = do_shrinker_shrink(shrinker, shrinkctl, - batch_size); - if (ret == -1) - break; - if (ret < nr_before) - freed += nr_before - ret; - } + if (!(shrinker->flags & SHRINKER_NUMA_AWARE) && + (shrinkctl->nid != 0)) + break; - count_vm_events(SLABS_SCANNED, batch_size); - total_scan -= batch_size; + freed += shrink_slab_node(shrinkctl, shrinker, + nr_pages_scanned, lru_pages); - cond_resched(); } - - /* - * 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. - */ - if (total_scan > 0) - new_nr = atomic_long_add_return(total_scan, - &shrinker->nr_in_batch); - else - new_nr = atomic_long_read(&shrinker->nr_in_batch); - - trace_mm_shrink_slab_end(shrinker, freed, nr, new_nr); } up_read(&shrinker_rwsem); out: |