f2fs: enable rb-tree extent cache
This patch enables rb-tree based extent cache in f2fs.
When we mount with "-o extent_cache", f2fs will try to add recently accessed
page-block mappings into rb-tree based extent cache as much as possible, instead
of original one extent info cache.
By this way, f2fs can support more effective cache between dnode page cache and
disk. It will supply high hit ratio in the cache with fewer memory when dnode
page cache are reclaimed in environment of low memory.
Storage: Sandisk sd card 64g
1.append write file (offset: 0, size: 128M);
2.override write file (offset: 2M, size: 1M);
3.override write file (offset: 4M, size: 1M);
...
4.override write file (offset: 48M, size: 1M);
...
5.override write file (offset: 112M, size: 1M);
6.sync
7.echo 3 > /proc/sys/vm/drop_caches
8.read file (size:128M, unit: 4k, count: 32768)
(time dd if=/mnt/f2fs/128m bs=4k count=32768)
Extent Hit Ratio:
before patched
Hit Ratio 121 / 1071 1071 / 1071
Performance:
before patched
real 0m37.051s 0m35.556s
user 0m0.040s 0m0.026s
sys 0m2.990s 0m2.251s
Memory Cost:
before patched
Tree Count: 0 1 (size: 24 bytes)
Node Count: 0 45 (size: 1440 bytes)
v3:
o retest and given more details of test result.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f527453..acdc076 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -666,6 +666,9 @@
void **slot;
unsigned int found;
+ if (!test_opt(sbi, EXTENT_CACHE))
+ return;
+
if (available_free_memory(sbi, EXTENT_CACHE))
return;
@@ -714,6 +717,9 @@
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et;
+ if (!test_opt(sbi, EXTENT_CACHE))
+ return;
+
down_read(&sbi->extent_tree_lock);
et = radix_tree_lookup(&sbi->extent_tree_root, inode->i_ino);
if (!et) {
@@ -749,6 +755,9 @@
static bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
struct extent_info *ei)
{
+ if (test_opt(F2FS_I_SB(inode), EXTENT_CACHE))
+ return f2fs_lookup_extent_tree(inode, pgofs, ei);
+
return lookup_extent_info(inode, pgofs, ei);
}
@@ -765,6 +774,10 @@
fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
dn->ofs_in_node;
+ if (test_opt(F2FS_I_SB(dn->inode), EXTENT_CACHE))
+ return f2fs_update_extent_tree(dn->inode, fofs,
+ dn->data_blkaddr);
+
if (update_extent_info(dn->inode, fofs, dn->data_blkaddr))
sync_inode_page(dn);
}