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Subject[PATCH 1/2] f2fs: introduce a radix_tree for the free_nid list
Date
This patch introduces a radix tree for the list of free_nids, which enhances
the performance on free nid management.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
---
fs/f2fs/f2fs.h | 1 +
fs/f2fs/node.c | 36 +++++++++++++++++-------------------
2 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c56e67b..11fd8be 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -247,6 +247,7 @@ struct f2fs_nm_info {
struct list_head dirty_nat_entries; /* cached nat entry list (dirty) */

/* free node ids management */
+ struct radix_tree_root free_nid_root;/* root of the free_nid cache */
struct list_head free_nid_list; /* a list for free nids */
spinlock_t free_nid_list_lock; /* protect free nid list */
unsigned int fcnt; /* the number of free node id */
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 431bcb4..1f9cf21 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1269,21 +1269,17 @@ const struct address_space_operations f2fs_node_aops = {
.releasepage = f2fs_release_node_page,
};

-static struct free_nid *__lookup_free_nid_list(nid_t n, struct list_head *head)
+static struct free_nid *__lookup_free_nid_list(struct f2fs_nm_info *nm_i,
+ nid_t n)
{
- struct list_head *this;
- struct free_nid *i;
- list_for_each(this, head) {
- i = list_entry(this, struct free_nid, list);
- if (i->nid == n)
- return i;
- }
- return NULL;
+ return radix_tree_lookup(&nm_i->free_nid_root, n);
}

-static void __del_from_free_nid_list(struct free_nid *i)
+static void __del_from_free_nid_list(struct f2fs_nm_info *nm_i,
+ struct free_nid *i)
{
list_del(&i->list);
+ radix_tree_delete(&nm_i->free_nid_root, i->nid);
kmem_cache_free(free_nid_slab, i);
}

@@ -1304,7 +1300,8 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
/* do not add allocated nids */
read_lock(&nm_i->nat_tree_lock);
ne = __lookup_nat_cache(nm_i, nid);
- if (ne && nat_get_blkaddr(ne) != NULL_ADDR)
+ if (ne &&
+ (!ne->checkpointed || nat_get_blkaddr(ne) != NULL_ADDR))
allocated = true;
read_unlock(&nm_i->nat_tree_lock);
if (allocated)
@@ -1316,7 +1313,7 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
i->state = NID_NEW;

spin_lock(&nm_i->free_nid_list_lock);
- if (__lookup_free_nid_list(nid, &nm_i->free_nid_list)) {
+ if (radix_tree_insert(&nm_i->free_nid_root, i->nid, i)) {
spin_unlock(&nm_i->free_nid_list_lock);
kmem_cache_free(free_nid_slab, i);
return 0;
@@ -1331,9 +1328,9 @@ static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
{
struct free_nid *i;
spin_lock(&nm_i->free_nid_list_lock);
- i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
+ i = __lookup_free_nid_list(nm_i, nid);
if (i && i->state == NID_NEW) {
- __del_from_free_nid_list(i);
+ __del_from_free_nid_list(nm_i, i);
nm_i->fcnt--;
}
spin_unlock(&nm_i->free_nid_list_lock);
@@ -1457,9 +1454,9 @@ void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
struct free_nid *i;

spin_lock(&nm_i->free_nid_list_lock);
- i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
+ i = __lookup_free_nid_list(nm_i, nid);
f2fs_bug_on(!i || i->state != NID_ALLOC);
- __del_from_free_nid_list(i);
+ __del_from_free_nid_list(nm_i, i);
spin_unlock(&nm_i->free_nid_list_lock);
}

@@ -1475,10 +1472,10 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
return;

spin_lock(&nm_i->free_nid_list_lock);
- i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
+ i = __lookup_free_nid_list(nm_i, nid);
f2fs_bug_on(!i || i->state != NID_ALLOC);
if (nm_i->fcnt > 2 * MAX_FREE_NIDS) {
- __del_from_free_nid_list(i);
+ __del_from_free_nid_list(nm_i, i);
} else {
i->state = NID_NEW;
nm_i->fcnt++;
@@ -1812,6 +1809,7 @@ static int init_node_manager(struct f2fs_sb_info *sbi)
nm_i->fcnt = 0;
nm_i->nat_cnt = 0;

+ INIT_RADIX_TREE(&nm_i->free_nid_root, GFP_ATOMIC);
INIT_LIST_HEAD(&nm_i->free_nid_list);
INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
INIT_LIST_HEAD(&nm_i->nat_entries);
@@ -1865,7 +1863,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
spin_lock(&nm_i->free_nid_list_lock);
list_for_each_entry_safe(i, next_i, &nm_i->free_nid_list, list) {
f2fs_bug_on(i->state == NID_ALLOC);
- __del_from_free_nid_list(i);
+ __del_from_free_nid_list(nm_i, i);
nm_i->fcnt--;
}
f2fs_bug_on(nm_i->fcnt);
--
1.8.4.474.g128a96c


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