From a870acd9b2671de56514a430edfa7867823c31c9 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 24 Apr 2011 19:06:14 +0000 Subject: xfs: optimize AGFL refills While we need to make sure we do not reuse busy extents, there is no need to force out busy extents when moving them between the AGFL and the freespace btree as we still take care of that when doing the real allocation. To avoid the log force when just moving extents from the different free space tracking structures, move the busy search out of xfs_alloc_get_freelist into the callers that need it, and move the busy list insert from xfs_free_ag_extent which is used both by AGFL refills and real allocation to xfs_free_extent, which is only used by the latter. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/xfs_alloc_btree.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/xfs/xfs_alloc_btree.c') diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c index 3916925e2584..bcfe92f47edd 100644 --- a/fs/xfs/xfs_alloc_btree.c +++ b/fs/xfs/xfs_alloc_btree.c @@ -94,6 +94,8 @@ xfs_allocbt_alloc_block( *stat = 0; return 0; } + if (xfs_alloc_busy_search(cur->bc_mp, cur->bc_private.a.agno, bno, 1)) + xfs_trans_set_sync(cur->bc_tp); xfs_trans_agbtree_delta(cur->bc_tp, 1); new->s = cpu_to_be32(bno); -- cgit v1.2.3 From 97d3ac75e5e0ebf7ca38ae74cebd201c09b97ab2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 24 Apr 2011 19:06:16 +0000 Subject: xfs: exact busy extent tracking Update the extent tree in case we have to reuse a busy extent, so that it always is kept uptodate. This is done by replacing the busy list searches with a new xfs_alloc_busy_reuse helper, which updates the busy extent tree in case of a reuse. This allows us to allow reusing metadata extents unconditionally, and thus avoid log forces especially for allocation btree blocks. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/xfs_alloc_btree.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) (limited to 'fs/xfs/xfs_alloc_btree.c') diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c index bcfe92f47edd..8b469d53599f 100644 --- a/fs/xfs/xfs_alloc_btree.c +++ b/fs/xfs/xfs_alloc_btree.c @@ -94,8 +94,8 @@ xfs_allocbt_alloc_block( *stat = 0; return 0; } - if (xfs_alloc_busy_search(cur->bc_mp, cur->bc_private.a.agno, bno, 1)) - xfs_trans_set_sync(cur->bc_tp); + + xfs_alloc_busy_reuse(cur->bc_mp, cur->bc_private.a.agno, bno, 1, false); xfs_trans_agbtree_delta(cur->bc_tp, 1); new->s = cpu_to_be32(bno); @@ -120,17 +120,6 @@ xfs_allocbt_free_block( if (error) return error; - /* - * Since blocks move to the free list without the coordination used in - * xfs_bmap_finish, we can't allow block to be available for - * reallocation and non-transaction writing (user data) until we know - * that the transaction that moved it to the free list is permanently - * on disk. We track the blocks by declaring these blocks as "busy"; - * the busy list is maintained on a per-ag basis and each transaction - * records which entries should be removed when the iclog commits to - * disk. If a busy block is allocated, the iclog is pushed up to the - * LSN that freed the block. - */ xfs_alloc_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1); xfs_trans_agbtree_delta(cur->bc_tp, -1); return 0; -- cgit v1.2.3 From 55a7bc5a30ff2d30d8a34fea2af9fc601b32e61a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 4 May 2011 18:55:15 +0000 Subject: xfs: do not discard alloc btree blocks Blocks for the allocation btree are allocated from and released to the AGFL, and thus frequently reused. Even worse we do not have an easy way to avoid using an AGFL block when it is discarded due to the simple FILO list of free blocks, and thus can frequently stall on blocks that are currently undergoing a discard. Add a flag to the busy extent tracking structure to skip the discard for allocation btree blocks. In normal operation these blocks are reused frequently enough that there is no need to discard them anyway, but if they spill over to the allocation btree as part of a balance we "leak" blocks that we would otherwise discard. We could fix this by adding another flag and keeping these block in the rbtree even after they aren't busy any more so that we could discard them when they migrate out of the AGFL. Given that this would cause significant overhead I don't think it's worthwile for now. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/xfs_alloc_btree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_alloc_btree.c') diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c index 8b469d53599f..2b3518826a69 100644 --- a/fs/xfs/xfs_alloc_btree.c +++ b/fs/xfs/xfs_alloc_btree.c @@ -120,7 +120,8 @@ xfs_allocbt_free_block( if (error) return error; - xfs_alloc_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1); + xfs_alloc_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1, + XFS_ALLOC_BUSY_SKIP_DISCARD); xfs_trans_agbtree_delta(cur->bc_tp, -1); return 0; } -- cgit v1.2.3