diff options
| -rw-r--r-- | drivers/md/raid5.c | 68 | ||||
| -rw-r--r-- | drivers/md/raid5.h | 11 |
2 files changed, 71 insertions, 8 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index b7cd32e7f29e..9716319cc477 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -672,8 +672,13 @@ get_active_stripe(struct r5conf *conf, sector_t sector, *(conf->hash_locks + hash)); sh = __find_stripe(conf, sector, conf->generation - previous); if (!sh) { - if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) + if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) { sh = get_free_stripe(conf, hash); + if (!sh && llist_empty(&conf->released_stripes) && + !test_bit(R5_DID_ALLOC, &conf->cache_state)) + set_bit(R5_ALLOC_MORE, + &conf->cache_state); + } if (noblock && sh == NULL) break; if (!sh) { @@ -5761,6 +5766,8 @@ static void raid5d(struct md_thread *thread) int batch_size, released; released = release_stripe_list(conf, conf->temp_inactive_list); + if (released) + clear_bit(R5_DID_ALLOC, &conf->cache_state); if ( !list_empty(&conf->bitmap_list)) { @@ -5799,6 +5806,13 @@ static void raid5d(struct md_thread *thread) pr_debug("%d stripes handled\n", handled); spin_unlock_irq(&conf->device_lock); + if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state)) { + grow_one_stripe(conf, __GFP_NOWARN); + /* Set flag even if allocation failed. This helps + * slow down allocation requests when mem is short + */ + set_bit(R5_DID_ALLOC, &conf->cache_state); + } async_tx_issue_pending_all(); blk_finish_plug(&plug); @@ -5814,7 +5828,7 @@ raid5_show_stripe_cache_size(struct mddev *mddev, char *page) spin_lock(&mddev->lock); conf = mddev->private; if (conf) - ret = sprintf(page, "%d\n", conf->max_nr_stripes); + ret = sprintf(page, "%d\n", conf->min_nr_stripes); spin_unlock(&mddev->lock); return ret; } @@ -5828,10 +5842,12 @@ raid5_set_cache_size(struct mddev *mddev, int size) if (size <= 16 || size > 32768) return -EINVAL; + conf->min_nr_stripes = size; while (size < conf->max_nr_stripes && drop_one_stripe(conf)) ; + err = md_allow_write(mddev); if (err) return err; @@ -5947,7 +5963,7 @@ raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len) conf = mddev->private; if (!conf) err = -ENODEV; - else if (new > conf->max_nr_stripes) + else if (new > conf->min_nr_stripes) err = -EINVAL; else conf->bypass_threshold = new; @@ -6228,6 +6244,8 @@ static void raid5_free_percpu(struct r5conf *conf) static void free_conf(struct r5conf *conf) { + if (conf->shrinker.seeks) + unregister_shrinker(&conf->shrinker); free_thread_groups(conf); shrink_stripes(conf); raid5_free_percpu(conf); @@ -6295,6 +6313,30 @@ static int raid5_alloc_percpu(struct r5conf *conf) return err; } +static unsigned long raid5_cache_scan(struct shrinker *shrink, + struct shrink_control *sc) +{ + struct r5conf *conf = container_of(shrink, struct r5conf, shrinker); + int ret = 0; + while (ret < sc->nr_to_scan) { + if (drop_one_stripe(conf) == 0) + return SHRINK_STOP; + ret++; + } + return ret; +} + +static unsigned long raid5_cache_count(struct shrinker *shrink, + struct shrink_control *sc) +{ + struct r5conf *conf = container_of(shrink, struct r5conf, shrinker); + + if (conf->max_nr_stripes < conf->min_nr_stripes) + /* unlikely, but not impossible */ + return 0; + return conf->max_nr_stripes - conf->min_nr_stripes; +} + static struct r5conf *setup_conf(struct mddev *mddev) { struct r5conf *conf; @@ -6445,10 +6487,11 @@ static struct r5conf *setup_conf(struct mddev *mddev) conf->prev_algo = mddev->layout; } - memory = NR_STRIPES * (sizeof(struct stripe_head) + + conf->min_nr_stripes = NR_STRIPES; + memory = conf->min_nr_stripes * (sizeof(struct stripe_head) + max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS); - if (grow_stripes(conf, NR_STRIPES)) { + if (grow_stripes(conf, conf->min_nr_stripes)) { printk(KERN_ERR "md/raid:%s: couldn't allocate %dkB for buffers\n", mdname(mddev), memory); @@ -6456,6 +6499,17 @@ static struct r5conf *setup_conf(struct mddev *mddev) } else printk(KERN_INFO "md/raid:%s: allocated %dkB\n", mdname(mddev), memory); + /* + * Losing a stripe head costs more than the time to refill it, + * it reduces the queue depth and so can hurt throughput. + * So set it rather large, scaled by number of devices. + */ + conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4; + conf->shrinker.scan_objects = raid5_cache_scan; + conf->shrinker.count_objects = raid5_cache_count; + conf->shrinker.batch = 128; + conf->shrinker.flags = 0; + register_shrinker(&conf->shrinker); sprintf(pers_name, "raid%d", mddev->new_level); conf->thread = md_register_thread(raid5d, mddev, pers_name); @@ -7097,9 +7151,9 @@ static int check_stripe_cache(struct mddev *mddev) */ struct r5conf *conf = mddev->private; if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4 - > conf->max_nr_stripes || + > conf->min_nr_stripes || ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4 - > conf->max_nr_stripes) { + > conf->min_nr_stripes) { printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes. Needed %lu\n", mdname(mddev), ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9) diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index ebe4e24bc14d..7dc0dd86074b 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -433,6 +433,7 @@ struct r5conf { int max_degraded; int raid_disks; int max_nr_stripes; + int min_nr_stripes; /* reshape_progress is the leading edge of a 'reshape' * It has value MaxSector when no reshape is happening @@ -513,7 +514,15 @@ struct r5conf { #define R5_INACTIVE_BLOCKED 1 /* release of inactive stripes blocked, * waiting for 25% to be free */ - +#define R5_ALLOC_MORE 2 /* It might help to allocate another + * stripe. + */ +#define R5_DID_ALLOC 4 /* A stripe was allocated, don't allocate + * more until at least one has been + * released. This avoids flooding + * the cache. + */ + struct shrinker shrinker; int pool_size; /* number of disks in stripeheads in pool */ spinlock_t device_lock; struct disk_info *disks; |