Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[linux-2.6.git] / fs / btrfs / extent-tree.c
index e238a0cdac677c06b1774018bf549b03399da4c8..94627c4cc193343aacc82b3aca1a6e9eaaefd8dd 100644 (file)
@@ -2977,10 +2977,10 @@ static int maybe_allocate_chunk(struct btrfs_root *root,
 
        free_space = btrfs_super_total_bytes(disk_super);
        /*
-        * we allow the metadata to grow to a max of either 5gb or 5% of the
+        * we allow the metadata to grow to a max of either 10gb or 5% of the
         * space in the volume.
         */
-       min_metadata = min((u64)5 * 1024 * 1024 * 1024,
+       min_metadata = min((u64)10 * 1024 * 1024 * 1024,
                             div64_u64(free_space * 5, 100));
        if (info->total_bytes >= min_metadata) {
                spin_unlock(&info->lock);
@@ -4102,7 +4102,7 @@ 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,
@@ -4131,12 +4131,15 @@ 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);
@@ -4172,14 +4175,19 @@ 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) {
@@ -4191,13 +4199,13 @@ 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) {
@@ -4209,28 +4217,45 @@ 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;
 
@@ -4410,9 +4435,11 @@ 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
@@ -4421,12 +4448,47 @@ 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) {
@@ -4438,7 +4500,8 @@ 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;
                }