[PATCH 5/5] ext4: expand next_linear_group to remove repeat check for linear scan.

From: Kemeng Shi
Date: Tue Mar 26 2024 - 09:46:41 EST


Expand next_linear_group to remove repat check for linear scan.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 37 ++++++-------------------------------
1 file changed, 6 insertions(+), 31 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 0f8a34513bf6..561780a274cd 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1075,31 +1075,6 @@ static inline int should_optimize_scan(struct ext4_allocation_context *ac)
return 1;
}

-/*
- * Return next linear group for allocation. If linear traversal should not be
- * performed, this function just returns the same group
- */
-static ext4_group_t
-next_linear_group(struct ext4_allocation_context *ac, 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.
- */
- return group + 1 >= ngroups ? 0 : group + 1;
-}
-
/*
* ext4_mb_choose_next_group: choose next group for allocation.
*
@@ -1118,12 +1093,12 @@ 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);
- return;
- }
-
- if (*new_cr == CR_POWER2_ALIGNED) {
+ if (!should_optimize_scan(ac))
+ *group = *group + 1 >= ngroups ? 0 : *group + 1;
+ else if (ac->ac_groups_linear_remaining) {
+ ac->ac_groups_linear_remaining--;
+ *group = *group + 1 >= ngroups ? 0 : *group + 1;
+ } else if (*new_cr == CR_POWER2_ALIGNED) {
ext4_mb_choose_next_group_p2_aligned(ac, new_cr, group);
} else if (*new_cr == CR_GOAL_LEN_FAST) {
ext4_mb_choose_next_group_goal_fast(ac, new_cr, group);
--
2.30.0