From: Yang Guo <guoyang2@xxxxxxxxxx>
percpu_counter_compare will be called by xfs_mod_icount/ifree to check
whether the counter less than 0 and it is a expensive function.
let's check it only when delta < 0, it will be good for xfs's performance.
Cc: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Signed-off-by: Yang Guo <guoyang2@xxxxxxxxxx>
Signed-off-by: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
---
fs/xfs/xfs_mount.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index ba5b6f3b2b88..5e8314e6565e 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1174,6 +1174,9 @@ xfs_mod_icount(
int64_t delta)
{
percpu_counter_add_batch(&mp->m_icount, delta, XFS_ICOUNT_BATCH);
+ if (delta > 0)
+ return 0;
+
if (__percpu_counter_compare(&mp->m_icount, 0, XFS_ICOUNT_BATCH) < 0) {
ASSERT(0);
percpu_counter_add(&mp->m_icount, -delta);
@@ -1188,6 +1191,9 @@ xfs_mod_ifree(
int64_t delta)
{
percpu_counter_add(&mp->m_ifree, delta);
+ if (delta > 0)
+ return 0;
+
if (percpu_counter_compare(&mp->m_ifree, 0) < 0) {
ASSERT(0);
percpu_counter_add(&mp->m_ifree, -delta);
--
2.7.4
