ext4: use percpu_counters for extent_status cache hits/misses

@es_stats_cache_hits and @es_stats_cache_misses are accessed frequently in
ext4_es_lookup_extent function, it would influence the ext4 read/write
performance in NUMA system. Let's optimize it using percpu_counter,
it is profitable for the performance.

The test command is as below:
fio -name=randwrite -numjobs=8 -filename=/mnt/test1 -rw=randwrite
-ioengine=libaio -direct=1 -iodepth=64 -sync=0 -norandommap
-group_reporting -runtime=120 -time_based -bs=4k -size=5G

And the result is better 10% than the initial implement:
without the patch，IOPS=197k, BW=770MiB/s (808MB/s)(90.3GiB/120002msec)
with the patch,  IOPS=218k, BW=852MiB/s (894MB/s)(99.9GiB/120002msec)

Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Yang Guo <guoyang2@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 5efbb116fba035dc5617eb8047ca753f3cc6d31e..d996b44d2265b581be5db2b297065f9a745a9dad 100644 (file)
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -948,7 +948,7 @@ int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
                es->es_pblk = es1->es_pblk;
                if (!ext4_es_is_referenced(es1))
                        ext4_es_set_referenced(es1);
-               stats->es_stats_cache_hits++;
+               percpu_counter_inc(&stats->es_stats_cache_hits);
                if (next_lblk) {
                        node = rb_next(&es1->rb_node);
                        if (node) {
@@ -959,7 +959,7 @@ int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
                                *next_lblk = 0;
                }
        } else {
-               stats->es_stats_cache_misses++;
+               percpu_counter_inc(&stats->es_stats_cache_misses);
        }
 
        read_unlock(&EXT4_I(inode)->i_es_lock);
@@ -1586,9 +1586,9 @@ int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v)
        seq_printf(seq, "stats:\n  %lld objects\n  %lld reclaimable objects\n",
                   percpu_counter_sum_positive(&es_stats->es_stats_all_cnt),
                   percpu_counter_sum_positive(&es_stats->es_stats_shk_cnt));
-       seq_printf(seq, "  %lu/%lu cache hits/misses\n",
-                  es_stats->es_stats_cache_hits,
-                  es_stats->es_stats_cache_misses);
+       seq_printf(seq, "  %lld/%lld cache hits/misses\n",
+                  percpu_counter_sum_positive(&es_stats->es_stats_cache_hits),
+                  percpu_counter_sum_positive(&es_stats->es_stats_cache_misses));
        if (inode_cnt)
                seq_printf(seq, "  %d inodes on list\n", inode_cnt);
 
@@ -1615,35 +1615,46 @@ int ext4_es_register_shrinker(struct ext4_sb_info *sbi)
        sbi->s_es_nr_inode = 0;
        spin_lock_init(&sbi->s_es_lock);
        sbi->s_es_stats.es_stats_shrunk = 0;
-       sbi->s_es_stats.es_stats_cache_hits = 0;
-       sbi->s_es_stats.es_stats_cache_misses = 0;
+       err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_hits, 0,
+                                 GFP_KERNEL);
+       if (err)
+               return err;
+       err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_misses, 0,
+                                 GFP_KERNEL);
+       if (err)
+               goto err1;
        sbi->s_es_stats.es_stats_scan_time = 0;
        sbi->s_es_stats.es_stats_max_scan_time = 0;
        err = percpu_counter_init(&sbi->s_es_stats.es_stats_all_cnt, 0, GFP_KERNEL);
        if (err)
-               return err;
+               goto err2;
        err = percpu_counter_init(&sbi->s_es_stats.es_stats_shk_cnt, 0, GFP_KERNEL);
        if (err)
-               goto err1;
+               goto err3;
 
        sbi->s_es_shrinker.scan_objects = ext4_es_scan;
        sbi->s_es_shrinker.count_objects = ext4_es_count;
        sbi->s_es_shrinker.seeks = DEFAULT_SEEKS;
        err = register_shrinker(&sbi->s_es_shrinker);
        if (err)
-               goto err2;
+               goto err4;
 
        return 0;
-
-err2:
+err4:
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
-err1:
+err3:
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
+err2:
+       percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
+err1:
+       percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits);
        return err;
 }
 
 void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi)
 {
+       percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_hits);
+       percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
        unregister_shrinker(&sbi->s_es_shrinker);

diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 5e5c4a40d863b121fb24211d84740b1ba6326244..825313c59752621c73c6736522540dd6c90d1d08 100644 (file)
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -70,8 +70,8 @@ struct ext4_es_tree {
 
 struct ext4_es_stats {
        unsigned long es_stats_shrunk;
-       unsigned long es_stats_cache_hits;
-       unsigned long es_stats_cache_misses;
+       struct percpu_counter es_stats_cache_hits;
+       struct percpu_counter es_stats_cache_misses;
        u64 es_stats_scan_time;
        u64 es_stats_max_scan_time;
        struct percpu_counter es_stats_all_cnt;