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Subject[PATCH v2 5/5] ext4: open coding repeated check in next_linear_group
Date
Open coding repeated check in next_linear_group.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
fs/ext4/mballoc.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 71b2f9a18875..4afe5bb94bf4 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1076,23 +1076,11 @@ static inline int should_optimize_scan(struct ext4_allocation_context *ac)
}

/*
- * Return next linear group for allocation. If linear traversal should not be
- * performed, this function just returns the same group
+ * Return next linear group for allocation.
*/
static ext4_group_t
-next_linear_group(struct ext4_allocation_context *ac, ext4_group_t group,
- ext4_group_t ngroups)
+next_linear_group(ext4_group_t group, ext4_group_t ngroups)
{
- if (!should_optimize_scan(ac))
- goto inc_and_return;
-
- if (ac->ac_groups_linear_remaining) {
- ac->ac_groups_linear_remaining--;
- goto inc_and_return;
- }
-
- return group;
-inc_and_return:
/*
* Artificially restricted ngroups for non-extent
* files makes group > ngroups possible on first loop.
@@ -1118,8 +1106,19 @@ static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac,
{
*new_cr = ac->ac_criteria;

- if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) {
- *group = next_linear_group(ac, *group, ngroups);
+ if (!should_optimize_scan(ac)) {
+ *group = next_linear_group(*group, ngroups);
+ return;
+ }
+
+ /*
+ * Optimized scanning can return non adjacent groups which can cause
+ * seek overhead for rotational disks. So try few linear groups before
+ * trying optimized scan.
+ */
+ if (ac->ac_groups_linear_remaining) {
+ *group = next_linear_group(*group, ngroups);
+ ac->ac_groups_linear_remaining--;
return;
}

--
2.30.0

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