[RFC 10/11] ext4: Abstract out logic to search average fragment list

Ojaswin Mujoo
2023-01-27T12:40:04Z

Make the logic of searching average fragment list of a given order reusable
by abstracting it out to a differnet function. This will also avoid
code duplication in upcoming patches.

No functional changes.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
---
fs/ext4/mballoc.c | 51 ++++++++++++++++++++++++++++++-----------------
1 file changed, 33 insertions(+), 18 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 410c9636907b..1ce1174aea52 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -902,6 +902,37 @@ static void ext4_mb_choose_next_group_cr0(struct ext4_allocation_context *ac,
}
}

+/*
+ * Find a suitable group of given order from the average fragments list.
+ */
+static struct ext4_group_info *
+ext4_mb_find_good_group_avg_frag_lists(struct ext4_allocation_context *ac, int order)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct list_head *frag_list = &sbi->s_mb_avg_fragment_size[order];
+ rwlock_t *frag_list_lock = &sbi->s_mb_avg_fragment_size_locks[order];
+ struct ext4_group_info *grp = NULL, *iter;
+ enum criteria cr = ac->ac_criteria;
+
+ if (list_empty(frag_list))
+ return NULL;
+ read_lock(frag_list_lock);
+ if (list_empty(frag_list)) {
+ read_unlock(frag_list_lock);
+ return NULL;
+ }
+ list_for_each_entry(iter, frag_list, bb_avg_fragment_size_node) {
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]);
+ if (likely(ext4_mb_good_group(ac, iter->bb_group, cr))) {
+ grp = iter;
+ break;
+ }
+ }
+ read_unlock(frag_list_lock);
+ return grp;
+}
+
/*
* Choose next group by traversing average fragment size list of suitable
* order. Updates *new_cr if cr level needs an update.
@@ -910,7 +941,7 @@ static void ext4_mb_choose_next_group_cr1(struct ext4_allocation_context *ac,
enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
- struct ext4_group_info *grp = NULL, *iter;
+ struct ext4_group_info *grp = NULL;
int i;

if (unlikely(ac->ac_flags & EXT4_MB_CR1_OPTIMIZED)) {
@@ -920,23 +951,7 @@ static void ext4_mb_choose_next_group_cr1(struct ext4_allocation_context *ac,

for (i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len);
i < MB_NUM_ORDERS(ac->ac_sb); i++) {
- if (list_empty(&sbi->s_mb_avg_fragment_size[i]))
- continue;
- read_lock(&sbi->s_mb_avg_fragment_size_locks[i]);
- if (list_empty(&sbi->s_mb_avg_fragment_size[i])) {
- read_unlock(&sbi->s_mb_avg_fragment_size_locks[i]);
- continue;
- }
- list_for_each_entry(iter, &sbi->s_mb_avg_fragment_size[i],
- bb_avg_fragment_size_node) {
- if (sbi->s_mb_stats)
- atomic64_inc(&sbi->s_bal_cX_groups_considered[CR1]);
- if (likely(ext4_mb_good_group(ac, iter->bb_group, CR1))) {
- grp = iter;
- break;
- }
- }
- read_unlock(&sbi->s_mb_avg_fragment_size_locks[i]);
+ grp = ext4_mb_find_good_group_avg_frag_lists(ac, i);
if (grp)
break;
}
--
2.31.1