On May 26, 2021, at 2:43 AM, Wang Jianchao <jianchao.wan9@xxxxxxxxx> wrote:
>
> There is no functional change in this patch but just split the
> codes, which serachs free block and does trim, into a new function
> ext4_try_to_trim_range. This is preparing for the following async
> backgroup discard.
>
> Signed-off-by: Wang Jianchao <wangjianchao@xxxxxxxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
> ---
> fs/ext4/mballoc.c | 102 ++++++++++++++++++++++++++++++------------------------
> 1 file changed, 57 insertions(+), 45 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index d81f1fd22..f984f15 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -5685,6 +5685,54 @@ static int ext4_trim_extent(struct super_block *sb,
> return ret;
> }
>
> +static int ext4_try_to_trim_range(struct super_block *sb,
> + struct ext4_buddy *e4b, ext4_grpblk_t start,
> + ext4_grpblk_t max, ext4_grpblk_t minblocks)
> +{
> + ext4_grpblk_t next, count, free_count;
> + void *bitmap;
> + int ret = 0;
> +
> + bitmap = e4b->bd_bitmap;
> + start = (e4b->bd_info->bb_first_free > start) ?
> + e4b->bd_info->bb_first_free : start;
> + count = 0;
> + free_count = 0;
> +
> + while (start <= max) {
> + start = mb_find_next_zero_bit(bitmap, max + 1, start);
> + if (start > max)
> + break;
> + next = mb_find_next_bit(bitmap, max + 1, start);
> +
> + if ((next - start) >= minblocks) {
> + ret = ext4_trim_extent(sb, start, next - start, e4b);
> + if (ret && ret != -EOPNOTSUPP)
> + break;
> + ret = 0;
> + count += next - start;
> + }
> + free_count += next - start;
> + start = next + 1;
> +
> + if (fatal_signal_pending(current)) {
> + count = -ERESTARTSYS;
> + break;
> + }
> +
> + if (need_resched()) {
> + ext4_unlock_group(sb, e4b->bd_group);
> + cond_resched();
> + ext4_lock_group(sb, e4b->bd_group);
> + }
> +
> + if ((e4b->bd_info->bb_free - free_count) < minblocks)
> + break;
> + }
> +
> + return count;
> +}
> +
> /**
> * ext4_trim_all_free -- function to trim all free space in alloc. group
> * @sb: super block for file system
> @@ -5708,10 +5756,8 @@ static int ext4_trim_extent(struct super_block *sb,
> ext4_grpblk_t start, ext4_grpblk_t max,
> ext4_grpblk_t minblocks)
> {
> - void *bitmap;
> - ext4_grpblk_t next, count = 0, free_count = 0;
> struct ext4_buddy e4b;
> - int ret = 0;
> + int ret;
>
> trace_ext4_trim_all_free(sb, group, start, max);
>
> @@ -5721,57 +5767,23 @@ static int ext4_trim_extent(struct super_block *sb,
> ret, group);
> return ret;
> }
> - bitmap = e4b.bd_bitmap;
>
> ext4_lock_group(sb, group);
> - if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
> - minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
> - goto out;
> -
> - start = (e4b.bd_info->bb_first_free > start) ?
> - e4b.bd_info->bb_first_free : start;
>
> - while (start <= max) {
> - start = mb_find_next_zero_bit(bitmap, max + 1, start);
> - if (start > max)
> - break;
> - next = mb_find_next_bit(bitmap, max + 1, start);
> -
> - if ((next - start) >= minblocks) {
> - ret = ext4_trim_extent(sb, start, next - start, &e4b);
> - if (ret && ret != -EOPNOTSUPP)
> - break;
> - ret = 0;
> - count += next - start;
> - }
> - free_count += next - start;
> - start = next + 1;
> -
> - if (fatal_signal_pending(current)) {
> - count = -ERESTARTSYS;
> - break;
> - }
> -
> - if (need_resched()) {
> - ext4_unlock_group(sb, group);
> - cond_resched();
> - ext4_lock_group(sb, group);
> - }
> -
> - if ((e4b.bd_info->bb_free - free_count) < minblocks)
> - break;
> + if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
> + minblocks < atomic_read(&EXT4_SB(sb)->s_last_trim_minblks)) {
> + ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
> + if (ret >= 0)
> + EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
> + } else {
> + ret = 0;
> }
>
> - if (!ret) {
> - ret = count;
> - EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
> - }
> -out:
> ext4_unlock_group(sb, group);
> ext4_mb_unload_buddy(&e4b);
>
> ext4_debug("trimmed %d blocks in the group %d\n",
> - count, group);
> + ret, group);
>
> return ret;
> }
> --
> 1.8.3.1
Cheers, Andreas
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