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authorZheng Liu <wenqing.lz@taobao.com>2014-09-02 04:26:49 +0200
committerTheodore Ts'o <tytso@mit.edu>2014-09-02 04:26:49 +0200
commiteb68d0e2fc5a4e5c06324ea5f485fccbae626d05 (patch)
tree2615b7518bebee73f197efbf32df9b4b21f9969e /fs/ext4/extents_status.h
parentext4: improve extents status tree trace point (diff)
downloadlinux-eb68d0e2fc5a4e5c06324ea5f485fccbae626d05.tar.xz
linux-eb68d0e2fc5a4e5c06324ea5f485fccbae626d05.zip
ext4: track extent status tree shrinker delay statictics
This commit adds some statictics in extent status tree shrinker. The purpose to add these is that we want to collect more details when we encounter a stall caused by extent status tree shrinker. Here we count the following statictics: stats: the number of all objects on all extent status trees the number of reclaimable objects on lru list cache hits/misses the last sorted interval the number of inodes on lru list average: scan time for shrinking some objects the number of shrunk objects maximum: the inode that has max nr. of objects on lru list the maximum scan time for shrinking some objects The output looks like below: $ cat /proc/fs/ext4/sda1/es_shrinker_info stats: 28228 objects 6341 reclaimable objects 5281/631 cache hits/misses 586 ms last sorted interval 250 inodes on lru list average: 153 us scan time 128 shrunk objects maximum: 255 inode (255 objects, 198 reclaimable) 125723 us max scan time If the lru list has never been sorted, the following line will not be printed: 586ms last sorted interval If there is an empty lru list, the following lines also will not be printed: 250 inodes on lru list ... maximum: 255 inode (255 objects, 198 reclaimable) 0 us max scan time Meanwhile in this commit a new trace point is defined to print some details in __ext4_es_shrink(). Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents_status.h')
-rw-r--r--fs/ext4/extents_status.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index f1b62a419920..efd5f970b501 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -64,6 +64,17 @@ struct ext4_es_tree {
struct extent_status *cache_es; /* recently accessed extent */
};
+struct ext4_es_stats {
+ unsigned long es_stats_last_sorted;
+ unsigned long es_stats_shrunk;
+ unsigned long es_stats_cache_hits;
+ unsigned long es_stats_cache_misses;
+ u64 es_stats_scan_time;
+ u64 es_stats_max_scan_time;
+ struct percpu_counter es_stats_all_cnt;
+ struct percpu_counter es_stats_lru_cnt;
+};
+
extern int __init ext4_init_es(void);
extern void ext4_exit_es(void);
extern void ext4_es_init_tree(struct ext4_es_tree *tree);
@@ -138,7 +149,7 @@ static inline void ext4_es_store_pblock_status(struct extent_status *es,
(pb & ~ES_MASK));
}
-extern void ext4_es_register_shrinker(struct ext4_sb_info *sbi);
+extern int ext4_es_register_shrinker(struct ext4_sb_info *sbi);
extern void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi);
extern void ext4_es_lru_add(struct inode *inode);
extern void ext4_es_lru_del(struct inode *inode);