Hi Andrew,
Today's linux-next merge of the akpm tree got a conflict in
fs/ext4/extents_status.c between commit 6480bad916be ("ext4: improve
extent cache shrink mechanism to avoid to burn CPU time") from the ext
tree and commit 1f42d0934b4e ("fs: convert fs shrinkers to new scan/count
API") from the akpm tree.
I fixed it up (I am not sure if the result makes complete sense - see
below) and can carry the fix as necessary (no action is required).
--
Cheers,
Stephen Rothwell s...@canb.auug.org.au
diff --cc fs/ext4/extents_status.c
index 80dcc59,4bce4f0..0000000
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@@ -876,58 -878,32 +876,63 @@@ int ext4_es_zeroout(struct inode *inode
EXTENT_STATUS_WRITTEN);
}
+static int ext4_inode_touch_time_cmp(void *priv, struct list_head *a,
+ struct list_head *b)
+{
+ struct ext4_inode_info *eia, *eib;
+ unsigned long diff;
+
+ eia = list_entry(a, struct ext4_inode_info, i_es_lru);
+ eib = list_entry(b, struct ext4_inode_info, i_es_lru);
+
+ diff = eia->i_touch_when - eib->i_touch_when;
+ if (diff < 0)
+ return -1;
+ if (diff > 0)
+ return 1;
+ return 0;
+}
- static int ext4_es_shrink(struct shrinker *shrink, struct shrink_control *sc)
+ static long ext4_es_count(struct shrinker *shrink, struct shrink_control *sc)
+ {
+ long nr;
+ struct ext4_sb_info *sbi = container_of(shrink,
+ struct ext4_sb_info, s_es_shrinker);
+
+ nr = percpu_counter_read_positive(&sbi->s_extent_cache_cnt);
+ trace_ext4_es_shrink_enter(sbi->s_sb, sc->nr_to_scan, nr);
+ return nr;
+ }
+
+ static long ext4_es_scan(struct shrinker *shrink, struct shrink_control *sc)
{
struct ext4_sb_info *sbi = container_of(shrink,
struct ext4_sb_info, s_es_shrinker);
struct ext4_inode_info *ei;
- struct list_head *cur, *tmp, scanned;
+ struct list_head *cur, *tmp;
+ LIST_HEAD(skiped);
int nr_to_scan = sc->nr_to_scan;
- int ret, nr_shrunk = 0;
-
- ret = percpu_counter_read_positive(&sbi->s_extent_cache_cnt);
- trace_ext4_es_shrink_enter(sbi->s_sb, nr_to_scan, ret);
-
- if (!nr_to_scan)
- return ret;
+ int ret = 0, nr_shrunk = 0;
- INIT_LIST_HEAD(&scanned);
-
spin_lock(&sbi->s_es_lru_lock);
+
+ /*
+ * If the inode that is at the head of LRU list is newer than
+ * last_sorted time, that means that we need to sort this list.
+ */
+ ei = list_first_entry(&sbi->s_es_lru, struct ext4_inode_info, i_es_lru);
+ if (sbi->s_es_last_sorted < ei->i_touch_when) {
+ list_sort(NULL, &sbi->s_es_lru, ext4_inode_touch_time_cmp);
+ sbi->s_es_last_sorted = jiffies;
+ }
+
list_for_each_safe(cur, tmp, &sbi->s_es_lru) {
- list_move_tail(cur, &scanned);
+ /*
+ * If we have already reclaimed all extents from extent
+ * status tree, just stop the loop immediately.
+ */
+ if (percpu_counter_read_positive(&sbi->s_extent_cache_cnt) == 0)
+ break;
ei = list_entry(cur, struct ext4_inode_info, i_es_lru);
@@@ -951,22 -923,22 +956,22 @@@
if (nr_to_scan == 0)
break;
}
- list_splice_tail(&scanned, &sbi->s_es_lru);
+
+ /* Move the newer inodes into the tail of the LRU list. */
+ list_splice_tail(&skiped, &sbi->s_es_lru);
spin_unlock(&sbi->s_es_lru_lock);
- ret = percpu_counter_read_positive(&sbi->s_extent_cache_cnt);
trace_ext4_es_shrink_exit(sbi->s_sb, nr_shrunk, ret);
- return ret;
+ return nr_shrunk;
}
-void ext4_es_register_shrinker(struct super_block *sb)
+void ext4_es_register_shrinker(struct ext4_sb_info *sbi)
{
- struct ext4_sb_info *sbi;
-
- sbi = EXT4_SB(sb);
INIT_LIST_HEAD(&sbi->s_es_lru);
spin_lock_init(&sbi->s_es_lru_lock);
+ sbi->s_es_last_sorted = 0;
- sbi->s_es_shrinker.shrink = ext4_es_shrink;
+ 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;
register_shrinker(&sbi->s_es_shrinker);
}
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