This patch speeds up extent_node shrinker by introducing linked list.

Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
 fs/f2fs/extent_cache.c | 74 ++++++++++++++++++++++----------------------------
 fs/f2fs/f2fs.h         |  2 ++
 2 files changed, 35 insertions(+), 41 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index ccd5c63..18311ff 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -32,7 +32,9 @@ static struct extent_node *__attach_extent_node(struct 
f2fs_sb_info *sbi,
                return NULL;
 
        en->ei = *ei;
+       en->et = et;
        INIT_LIST_HEAD(&en->list);
+       INIT_LIST_HEAD(&en->vlist);
 
        rb_link_node(&en->rb_node, parent, p);
        rb_insert_color(&en->rb_node, &et->root);
@@ -129,7 +131,7 @@ static struct extent_node *__init_extent_tree(struct 
f2fs_sb_info *sbi,
 }
 
 static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
-                                       struct extent_tree *et, bool free_all)
+                                       struct extent_tree *et)
 {
        struct rb_node *node, *next;
        struct extent_node *en;
@@ -137,17 +139,19 @@ static unsigned int __free_extent_tree(struct 
f2fs_sb_info *sbi,
 
        node = rb_first(&et->root);
        while (node) {
+               bool need_free = false;
+
                next = rb_next(node);
                en = rb_entry(node, struct extent_node, rb_node);
 
-               if (free_all) {
-                       spin_lock(&sbi->extent_lock);
-                       if (!list_empty(&en->list))
-                               list_del_init(&en->list);
-                       spin_unlock(&sbi->extent_lock);
+               spin_lock(&sbi->extent_lock);
+               if (!list_empty(&en->list)) {
+                       list_del_init(&en->list);
+                       need_free = true;
                }
+               spin_unlock(&sbi->extent_lock);
 
-               if (free_all || list_empty(&en->list)) {
+               if (need_free) {
                        __detach_extent_node(sbi, et, en);
                        kmem_cache_free(extent_node_slab, en);
                }
@@ -438,6 +442,7 @@ static unsigned int f2fs_update_extent_tree_range(struct 
inode *inode,
        while (en && en->ei.fofs < end) {
                unsigned int org_end;
                int parts = 0;  /* # of parts current extent split into */
+               bool need_free = false;
 
                next_en = en1 = NULL;
 
@@ -493,14 +498,16 @@ static unsigned int f2fs_update_extent_tree_range(struct 
inode *inode,
 
                /* update in global extent list */
                spin_lock(&sbi->extent_lock);
-               if (!parts && !list_empty(&en->list))
+               if (!parts && !list_empty(&en->list)) {
                        list_del(&en->list);
+                       need_free = true;
+               }
                if (en1)
                        list_add_tail(&en1->list, &sbi->extent_list);
                spin_unlock(&sbi->extent_lock);
 
                /* release extent node */
-               if (!parts)
+               if (!parts && need_free)
                        kmem_cache_free(extent_node_slab, en);
 
                en = next_en;
@@ -509,6 +516,7 @@ static unsigned int f2fs_update_extent_tree_range(struct 
inode *inode,
        /* 3. update extent in extent cache */
        if (blkaddr) {
                struct extent_node *den = NULL;
+               bool need_free = false;
 
                set_extent_info(&ei, fofs, blkaddr, len);
                en1 = __try_merge_extent_node(sbi, et, &ei, &den,
@@ -532,16 +540,18 @@ static unsigned int f2fs_update_extent_tree_range(struct 
inode *inode,
                        else
                                list_move_tail(&en1->list, &sbi->extent_list);
                }
-               if (den && !list_empty(&den->list))
+               if (den && !list_empty(&den->list)) {
                        list_del(&den->list);
+                       need_free = true;
+               }
                spin_unlock(&sbi->extent_lock);
 
-               if (den)
+               if (den && need_free)
                        kmem_cache_free(extent_node_slab, den);
        }
 
        if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT))
-               __free_extent_tree(sbi, et, true);
+               __free_extent_tree(sbi, et);
 
        write_unlock(&et->lock);
 
@@ -550,14 +560,12 @@ static unsigned int f2fs_update_extent_tree_range(struct 
inode *inode,
 
 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
 {
-       struct extent_tree *treevec[EXT_TREE_VEC_SIZE];
        struct extent_tree *et, *next;
        struct extent_node *en, *tmp;
-       unsigned long ino = F2FS_ROOT_INO(sbi);
-       unsigned int found;
        unsigned int node_cnt = 0, tree_cnt = 0;
        int remained;
        bool do_free = false;
+       LIST_HEAD(victim_list);
 
        if (!test_opt(sbi, EXTENT_CACHE))
                return 0;
@@ -572,7 +580,7 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info 
*sbi, int nr_shrink)
        list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
                if (atomic_read(&et->node_cnt)) {
                        write_lock(&et->lock);
-                       node_cnt += __free_extent_tree(sbi, et, true);
+                       node_cnt += __free_extent_tree(sbi, et);
                        write_unlock(&et->lock);
                }
 
@@ -600,6 +608,8 @@ free_node:
                if (!remained--)
                        break;
                list_del_init(&en->list);
+               list_add_tail(&en->vlist, &victim_list);
+               tree_cnt++;
                do_free = true;
        }
        spin_unlock(&sbi->extent_lock);
@@ -607,31 +617,13 @@ free_node:
        if (do_free == false)
                goto unlock_out;
 
-       /*
-        * reset ino for searching victims from beginning of global extent tree.
-        */
-       ino = F2FS_ROOT_INO(sbi);
-
-       while ((found = radix_tree_gang_lookup(&sbi->extent_tree_root,
-                               (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
-               unsigned i;
-
-               ino = treevec[found - 1]->ino + 1;
-               for (i = 0; i < found; i++) {
-                       struct extent_tree *et = treevec[i];
-
-                       if (!atomic_read(&et->node_cnt))
-                               continue;
-
-                       if (write_trylock(&et->lock)) {
-                               node_cnt += __free_extent_tree(sbi, et, false);
-                               write_unlock(&et->lock);
-                       }
-
-                       if (node_cnt + tree_cnt >= nr_shrink)
-                               goto unlock_out;
-               }
+       list_for_each_entry_safe(en, tmp, &victim_list, vlist) {
+               write_lock(&en->et->lock);
+               __detach_extent_node(sbi, en->et, en);
+               write_unlock(&en->et->lock);
+               kmem_cache_free(extent_node_slab, en);
        }
+
 unlock_out:
        up_write(&sbi->extent_tree_lock);
 out:
@@ -650,7 +642,7 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode)
                return 0;
 
        write_lock(&et->lock);
-       node_cnt = __free_extent_tree(sbi, et, true);
+       node_cnt = __free_extent_tree(sbi, et);
        write_unlock(&et->lock);
 
        return node_cnt;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c4e723b..0bbbfed 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -353,7 +353,9 @@ struct extent_info {
 struct extent_node {
        struct rb_node rb_node;         /* rb node located in rb-tree */
        struct list_head list;          /* node in global extent list of sbi */
+       struct list_head vlist;         /* node in victim extent list */
        struct extent_info ei;          /* extent info */
+       struct extent_tree *et;         /* extent tree pointer */
 };
 
 struct extent_tree {
-- 
2.6.3

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