Commit 32c08693 authored by Kemeng Shi's avatar Kemeng Shi Committed by Theodore Ts'o

ext4: remove ac->ac_found > sbi->s_mb_min_to_scan dead check in ext4_mb_check_limits

Only call trace of ext4_mb_check_limits is as following:
ext4_mb_complex_scan_group
	ext4_mb_measure_extent
		ext4_mb_check_limits(ac, e4b, 0);
	ext4_mb_check_limits(ac, e4b, 1);

If the first ac->ac_found > sbi->s_mb_max_to_scan check in
ext4_mb_check_limits is met, we will set ac_status to
AC_STATUS_BREAK and call ext4_mb_try_best_found to try to use
ac->ac_b_ex.
If ext4_mb_try_best_found successes, then block allocation finishs,
the removed ac->ac_found > sbi->s_mb_min_to_scan check is not reachable.
If ext4_mb_try_best_found fails, then we set EXT4_MB_HINT_FIRST and
reset ac->ac_b_ex to retry block allocation. We will use any found
free extent in ext4_mb_measure_extent before reach the removed
ac->ac_found > sbi->s_mb_min_to_scan check.
In summary, the removed ac->ac_found > sbi->s_mb_min_to_scan check is
not reachable and we can remove that dead check.
Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: default avatarOjaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20230303172120.3800725-14-shikemeng@huaweicloud.comSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 976620bd
...@@ -2039,8 +2039,7 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac, ...@@ -2039,8 +2039,7 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
if (bex->fe_len < gex->fe_len) if (bex->fe_len < gex->fe_len)
return; return;
if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan) if (finish_group && bex->fe_group == e4b->bd_group) {
&& bex->fe_group == e4b->bd_group) {
/* recheck chunk's availability - we don't know /* recheck chunk's availability - we don't know
* when it was found (within this lock-unlock * when it was found (within this lock-unlock
* period or not) */ * period or not) */
......
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