summaryrefslogtreecommitdiffstats
path: root/fs/ext4/extents.c
diff options
context:
space:
mode:
authorYan, Zheng <zheng.z.yan@intel.com>2013-05-03 02:15:52 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-05-03 02:15:52 -0400
commite30b5dca15dea86aa697f9d58ff646294fe80d3d (patch)
tree549d1ff3f8e5ecb9675a2937113aa99e64ef3ea1 /fs/ext4/extents.c
parent0d606e2c9fccdd4e67febf1e2da500e1bfe9e045 (diff)
downloadlinux-e30b5dca15dea86aa697f9d58ff646294fe80d3d.tar.bz2
ext4: fix fio regression
We (Linux Kernel Performance project) found a regression introduced by commit: f7fec032aa ext4: track all extent status in extent status tree The commit causes about 20% performance decrease in fio random write test. Profiler shows that rb_next() uses a lot of CPU time. The call stack is: rb_next ext4_es_find_delayed_extent ext4_map_blocks _ext4_get_block ext4_get_block_write __blockdev_direct_IO ext4_direct_IO generic_file_direct_write __generic_file_aio_write ext4_file_write aio_rw_vect_retry aio_run_iocb do_io_submit sys_io_submit system_call_fastpath io_submit td_io_getevents io_u_queued_complete thread_main main __libc_start_main The cause is that ext4_es_find_delayed_extent() doesn't have an upper bound, it keeps searching until a delayed extent is found. When there are a lots of non-delayed entries in the extent state tree, ext4_es_find_delayed_extent() may uses a lot of CPU time. Reported-by: LKP project <lkp@linux.intel.com> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Cc: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents.c')
-rw-r--r--fs/ext4/extents.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 107936db244e..bc0f1910b9cf 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3642,7 +3642,7 @@ int ext4_find_delalloc_range(struct inode *inode,
{
struct extent_status es;
- ext4_es_find_delayed_extent(inode, lblk_start, &es);
+ ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
if (es.es_len == 0)
return 0; /* there is no delay extent in this tree */
else if (es.es_lblk <= lblk_start &&
@@ -4608,9 +4608,10 @@ static int ext4_find_delayed_extent(struct inode *inode,
struct extent_status es;
ext4_lblk_t block, next_del;
- ext4_es_find_delayed_extent(inode, newes->es_lblk, &es);
-
if (newes->es_pblk == 0) {
+ ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
+ newes->es_lblk + newes->es_len - 1, &es);
+
/*
* No extent in extent-tree contains block @newes->es_pblk,
* then the block may stay in 1)a hole or 2)delayed-extent.
@@ -4630,7 +4631,7 @@ static int ext4_find_delayed_extent(struct inode *inode,
}
block = newes->es_lblk + newes->es_len;
- ext4_es_find_delayed_extent(inode, block, &es);
+ ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
if (es.es_len == 0)
next_del = EXT_MAX_BLOCKS;
else