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ext4: factor out ext4_mb_scan_group()

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Extract ext4_mb_scan_group() to make the code clearer and to
prepare for the later conversion of 'choose group' to 'scan groups'.
No functional changes.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-15-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Baokun Li
2025-07-25 09:14:17 -04:00
committed by Theodore Ts'o
parent 5abd85f667
commit 9c08e42db9
2 changed files with 51 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files
fs/ext4/mballoc.c
+49 -44
View File
@@ -2845,12 +2845,56 @@ void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
}
}
static int ext4_mb_scan_group(struct ext4_allocation_context *ac,
ext4_group_t group)
{
int ret;
struct super_block *sb = ac->ac_sb;
enum criteria cr = ac->ac_criteria;
ext4_mb_might_prefetch(ac, group);
/* prevent unnecessary buddy loading. */
if (cr < CR_ANY_FREE && spin_is_locked(ext4_group_lock_ptr(sb, group)))
return 0;
/* This now checks without needing the buddy page */
ret = ext4_mb_good_group_nolock(ac, group, cr);
if (ret <= 0) {
if (!ac->ac_first_err)
ac->ac_first_err = ret;
return 0;
}
ret = ext4_mb_load_buddy(sb, group, ac->ac_e4b);
if (ret)
return ret;
/* skip busy group */
if (cr >= CR_ANY_FREE)
ext4_lock_group(sb, group);
else if (!ext4_try_lock_group(sb, group))
goto out_unload;
/* We need to check again after locking the block group. */
if (unlikely(!ext4_mb_good_group(ac, group, cr)))
goto out_unlock;
__ext4_mb_scan_group(ac);
out_unlock:
ext4_unlock_group(sb, group);
out_unload:
ext4_mb_unload_buddy(ac->ac_e4b);
return ret;
}
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t ngroups, group, i;
enum criteria new_cr, cr = CR_GOAL_LEN_FAST;
int err = 0, first_err = 0;
int err = 0;
struct ext4_sb_info *sbi;
struct super_block *sb;
struct ext4_buddy e4b;
@@ -2912,6 +2956,7 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
ac->ac_e4b = &e4b;
ac->ac_prefetch_ios = 0;
ac->ac_first_err = 0;
repeat:
for (; cr < EXT4_MB_NUM_CRS && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
ac->ac_criteria = cr;
@@ -2926,7 +2971,6 @@ repeat:
for (i = 0, new_cr = cr; i < ngroups; i++,
ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) {
int ret = 0;
cond_resched();
if (new_cr != cr) {
@@ -2934,49 +2978,10 @@ repeat:
goto repeat;
}
ext4_mb_might_prefetch(ac, group);
/* prevent unnecessary buddy loading. */
if (cr < CR_ANY_FREE &&
spin_is_locked(ext4_group_lock_ptr(sb, group)))
continue;
/* This now checks without needing the buddy page */
ret = ext4_mb_good_group_nolock(ac, group, cr);
if (ret <= 0) {
if (!first_err)
first_err = ret;
continue;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
err = ext4_mb_scan_group(ac, group);
if (err)
goto out;
/* skip busy group */
if (cr >= CR_ANY_FREE) {
ext4_lock_group(sb, group);
} else if (!ext4_try_lock_group(sb, group)) {
ext4_mb_unload_buddy(&e4b);
continue;
}
/*
* We need to check again after locking the
* block group
*/
ret = ext4_mb_good_group(ac, group, cr);
if (ret == 0) {
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
continue;
}
__ext4_mb_scan_group(ac);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
if (ac->ac_status != AC_STATUS_CONTINUE)
break;
}
@@ -3025,8 +3030,8 @@ repeat:
atomic_inc(&sbi->s_bal_stream_goals);
}
out:
if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
err = first_err;
if (!err && ac->ac_status != AC_STATUS_FOUND && ac->ac_first_err)
err = ac->ac_first_err;
mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
fs/ext4/mballoc.h
+2
View File
@@ -196,6 +196,8 @@ struct ext4_allocation_context {
unsigned int ac_prefetch_ios;
unsigned int ac_prefetch_nr;
int ac_first_err;
__u32 ac_flags; /* allocation hints */
__u32 ac_groups_linear_remaining;
__u16 ac_groups_scanned;