From 19af4f0f303d964884c8f34f42ec5e6cd52df56a Mon Sep 17 00:00:00 2001 From: hanjinke Date: Mon, 6 Jun 2022 23:53:05 +0800 Subject: [PATCH] ext4: reuse order and buddy in mb_mark_used when buddy split After each buddy split, mb_mark_used will search the proper order for the block which may consume some loop in mb_find_order_for_block. In fact, we can reuse the order and buddy generated by the buddy split. Reviewed by: lei.rao@intel.com Signed-off-by: hanjinke Link: https://lore.kernel.org/r/20220606155305.74146-1-hanjinke.666@bytedance.com Signed-off-by: Theodore Ts'o --- fs/ext4/mballoc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 9e06334771a39..b02f71f07289d 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1933,6 +1933,7 @@ static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) unsigned ret = 0; int len0 = len; void *buddy; + bool split = false; BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3)); BUG_ON(e4b->bd_group != ex->fe_group); @@ -1957,12 +1958,16 @@ static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) /* let's maintain buddy itself */ while (len) { - ord = mb_find_order_for_block(e4b, start); + if (!split) + ord = mb_find_order_for_block(e4b, start); if (((start >> ord) << ord) == start && len >= (1 << ord)) { /* the whole chunk may be allocated at once! */ mlen = 1 << ord; - buddy = mb_find_buddy(e4b, ord, &max); + if (!split) + buddy = mb_find_buddy(e4b, ord, &max); + else + split = false; BUG_ON((start >> ord) >= max); mb_set_bit(start >> ord, buddy); e4b->bd_info->bb_counters[ord]--; @@ -1989,6 +1994,7 @@ static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) mb_clear_bit(cur + 1, buddy); e4b->bd_info->bb_counters[ord]++; e4b->bd_info->bb_counters[ord]++; + split = true; } mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info); -- 2.39.5