diff options
| -rw-r--r-- | fs/btrfs/extent-tree.c | 109 |
1 files changed, 86 insertions, 23 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index c56f91639dc1..2a4cdceeb575 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4101,7 +4101,7 @@ wait_block_group_cache_done(struct btrfs_block_group_cache *cache) } enum btrfs_loop_type { - LOOP_CACHED_ONLY = 0, + LOOP_FIND_IDEAL = 0, LOOP_CACHING_NOWAIT = 1, LOOP_CACHING_WAIT = 2, LOOP_ALLOC_CHUNK = 3, @@ -4130,12 +4130,15 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_block_group_cache *block_group = NULL; int empty_cluster = 2 * 1024 * 1024; int allowed_chunk_alloc = 0; + int done_chunk_alloc = 0; struct btrfs_space_info *space_info; int last_ptr_loop = 0; int loop = 0; bool found_uncached_bg = false; bool failed_cluster_refill = false; bool failed_alloc = false; + u64 ideal_cache_percent = 0; + u64 ideal_cache_offset = 0; WARN_ON(num_bytes < root->sectorsize); btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY); @@ -4171,14 +4174,19 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, empty_cluster = 0; if (search_start == hint_byte) { +ideal_cache: block_group = btrfs_lookup_block_group(root->fs_info, search_start); /* * we don't want to use the block group if it doesn't match our * allocation bits, or if its not cached. + * + * However if we are re-searching with an ideal block group + * picked out then we don't care that the block group is cached. */ if (block_group && block_group_bits(block_group, data) && - block_group_cache_done(block_group)) { + (block_group->cached != BTRFS_CACHE_NO || + search_start == ideal_cache_offset)) { down_read(&space_info->groups_sem); if (list_empty(&block_group->list) || block_group->ro) { @@ -4190,13 +4198,13 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, */ btrfs_put_block_group(block_group); up_read(&space_info->groups_sem); - } else + } else { goto have_block_group; + } } else if (block_group) { btrfs_put_block_group(block_group); } } - search: down_read(&space_info->groups_sem); list_for_each_entry(block_group, &space_info->block_groups, list) { @@ -4208,28 +4216,45 @@ search: have_block_group: if (unlikely(block_group->cached == BTRFS_CACHE_NO)) { + u64 free_percent; + + free_percent = btrfs_block_group_used(&block_group->item); + free_percent *= 100; + free_percent = div64_u64(free_percent, + block_group->key.offset); + free_percent = 100 - free_percent; + if (free_percent > ideal_cache_percent && + likely(!block_group->ro)) { + ideal_cache_offset = block_group->key.objectid; + ideal_cache_percent = free_percent; + } + /* - * we want to start caching kthreads, but not too many - * right off the bat so we don't overwhelm the system, - * so only start them if there are less than 2 and we're - * in the initial allocation phase. + * We only want to start kthread caching if we are at + * the point where we will wait for caching to make + * progress, or if our ideal search is over and we've + * found somebody to start caching. */ if (loop > LOOP_CACHING_NOWAIT || - atomic_read(&space_info->caching_threads) < 2) { + (loop > LOOP_FIND_IDEAL && + atomic_read(&space_info->caching_threads) < 2)) { ret = cache_block_group(block_group); BUG_ON(ret); } - } - - cached = block_group_cache_done(block_group); - if (unlikely(!cached)) { found_uncached_bg = true; - /* if we only want cached bgs, loop */ - if (loop == LOOP_CACHED_ONLY) + /* + * If loop is set for cached only, try the next block + * group. + */ + if (loop == LOOP_FIND_IDEAL) goto loop; } + cached = block_group_cache_done(block_group); + if (unlikely(!cached)) + found_uncached_bg = true; + if (unlikely(block_group->ro)) goto loop; @@ -4409,9 +4434,11 @@ loop: } up_read(&space_info->groups_sem); - /* LOOP_CACHED_ONLY, only search fully cached block groups - * LOOP_CACHING_NOWAIT, search partially cached block groups, but - * dont wait foR them to finish caching + /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for + * for them to make caching progress. Also + * determine the best possible bg to cache + * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking + * caching kthreads as we move along * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching * LOOP_ALLOC_CHUNK, force a chunk allocation and try again * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try @@ -4420,12 +4447,47 @@ loop: if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE && (found_uncached_bg || empty_size || empty_cluster || allowed_chunk_alloc)) { - if (found_uncached_bg) { + if (loop == LOOP_FIND_IDEAL && found_uncached_bg) { found_uncached_bg = false; - if (loop < LOOP_CACHING_WAIT) { - loop++; + loop++; + if (!ideal_cache_percent && + atomic_read(&space_info->caching_threads)) goto search; - } + + /* + * 1 of the following 2 things have happened so far + * + * 1) We found an ideal block group for caching that + * is mostly full and will cache quickly, so we might + * as well wait for it. + * + * 2) We searched for cached only and we didn't find + * anything, and we didn't start any caching kthreads + * either, so chances are we will loop through and + * start a couple caching kthreads, and then come back + * around and just wait for them. This will be slower + * because we will have 2 caching kthreads reading at + * the same time when we could have just started one + * and waited for it to get far enough to give us an + * allocation, so go ahead and go to the wait caching + * loop. + */ + loop = LOOP_CACHING_WAIT; + search_start = ideal_cache_offset; + ideal_cache_percent = 0; + goto ideal_cache; + } else if (loop == LOOP_FIND_IDEAL) { + /* + * Didn't find a uncached bg, wait on anything we find + * next. + */ + loop = LOOP_CACHING_WAIT; + goto search; + } + + if (loop < LOOP_CACHING_WAIT) { + loop++; + goto search; } if (loop == LOOP_ALLOC_CHUNK) { @@ -4437,7 +4499,8 @@ loop: ret = do_chunk_alloc(trans, root, num_bytes + 2 * 1024 * 1024, data, 1); allowed_chunk_alloc = 0; - } else { + done_chunk_alloc = 1; + } else if (!done_chunk_alloc) { space_info->force_alloc = 1; } |