On Fri, Feb 10, 2023 at 03:48:19AM +0800, Kemeng Shi wrote:
> If any bex which meets bex->fe_len >= gex->fe_len is found, then it will
> always be used when complex scan of group that bex belongs to finishs.
> So there will not be any lock-unlock period.
>
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
> ---
> fs/ext4/mballoc.c | 14 ++------------
> 1 file changed, 2 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index e53f84de5018..c684758d6dbb 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2019,8 +2019,6 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
> struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
> struct ext4_free_extent *bex = &ac->ac_b_ex;
> struct ext4_free_extent *gex = &ac->ac_g_ex;
> - struct ext4_free_extent ex;
> - int max;
>
> if (ac->ac_status == AC_STATUS_FOUND)
> return;
> @@ -2039,16 +2037,8 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
> if (bex->fe_len < gex->fe_len)
> return;
>
> - if (finish_group && bex->fe_group == e4b->bd_group) {
> - /* recheck chunk's availability - we don't know
> - * when it was found (within this lock-unlock
> - * period or not) */
> - max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
> - if (max >= gex->fe_len) {
> - ext4_mb_use_best_found(ac, e4b);
> - return;
> - }
> - }
> + if (finish_group)
> + ext4_mb_use_best_found(ac, e4b);
> }
>
> /*
> --
> 2.30.0
>
Looks good. So when we have found bex > gex, then we wont have a lock
unlock period since we always allocate the bex when we reach the end of
group.
Just a small typo in the commit message (finshs -> finishes), but other
than that feel free to add:
Reviewed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
