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Commit ee16cc03 authored by Tristan Ye's avatar Tristan Ye
Browse files

Ocfs2/move_extents: helper to calculate the defraging length in one run. 



The helper is to calculate the defrag length in one run according to a threshold,
it will proceed doing defragmentation until the threshold was meet, and skip a
LARGE extent if any.

Signed-off-by: default avatarTristan Ye <tristan.ye@oracle.com>
parent e0847717

fs/ocfs2/move_extents.c

+30 −0
Original line number Diff line number Diff line
@@ -797,3 +797,33 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context, 


	return ret;

}



/*

 * Helper to calculate the defraging length in one run according to threshold.

 */

static void ocfs2_calc_extent_defrag_len(u32 *alloc_size, u32 *len_defraged,

					 u32 threshold, int *skip)

{

	if ((*alloc_size + *len_defraged) < threshold) {

		/*

		 * proceed defragmentation until we meet the thresh

		 */

		*len_defraged += *alloc_size;

	} else if (*len_defraged == 0) {

		/*

		 * XXX: skip a large extent.

		 */

		*skip = 1;

	} else {

		/*

		 * split this extent to coalesce with former pieces as

		 * to reach the threshold.

		 *

		 * we're done here with one cycle of defragmentation

		 * in a size of 'thresh', resetting 'len_defraged'

		 * forces a new defragmentation.

		 */

		*alloc_size = threshold - *len_defraged;

		*len_defraged = 0;

	}

}