Btrfs: allocator optimizations, truncate readahead

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 62 insertions, 14 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 1497ff98f0d3..e3c6bfea3751 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -12,6 +12,33 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                                btrfs_root *extent_root);
 
+static void reada_extent_leaves(struct btrfs_root *root,
+                                struct btrfs_path *path, u64 limit)
+{
+        struct btrfs_node *node;
+        int i;
+        int nritems;
+        u64 item_objectid;
+        u64 blocknr;
+        int slot;
+        int ret;
+
+        if (!path->nodes[1])
+                return;
+        node = btrfs_buffer_node(path->nodes[1]);
+        slot = path->slots[1] + 1;
+        nritems = btrfs_header_nritems(&node->header);
+        for (i = slot; i < nritems && i < slot + 8; i++) {
+                item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
+                if (item_objectid > limit)
+                        break;
+                blocknr = btrfs_node_blockptr(node, i);
+                ret = readahead_tree_block(root, blocknr);
+                if (ret)
+                        break;
+        }
+}
+
 static int cache_block_group(struct btrfs_root *root,
                              struct btrfs_block_group_cache *block_group)
 {
@@ -24,6 +51,7 @@ static int cache_block_group(struct btrfs_root *root,
         u64 i;
         u64 last = 0;
         u64 hole_size;
+        u64 limit;
         int found = 0;
 
         root = root->fs_info->extent_root;
@@ -46,14 +74,17 @@ printk("cache block group %Lu\n", block_group->key.objectid);
                 return ret;
         if (ret && path->slots[0] > 0)
                 path->slots[0]--;
+        limit = block_group->key.objectid + block_group->key.offset;
+        reada_extent_leaves(root, path, limit);
         while(1) {
                 leaf = btrfs_buffer_leaf(path->nodes[0]);
                 slot = path->slots[0];
                 if (slot >= btrfs_header_nritems(&leaf->header)) {
+                        reada_extent_leaves(root, path, limit);
                         ret = btrfs_next_leaf(root, path);
-                        if (ret == 0)
+                        if (ret == 0) {
                                 continue;
-                        else {
+                        } else {
                                 if (found) {
                                         hole_size = block_group->key.objectid +
                                                 block_group->key.offset - last;
@@ -187,7 +218,7 @@ new_group:
                 return max((*cache_ret)->last_alloc, search_start);
         }
         cache = btrfs_find_block_group(root, cache,
-                                       last + cache->key.offset - 1, 0);
+                                       last + cache->key.offset - 1, 0, 0);
         *cache_ret = cache;
         goto again;
 }
@@ -195,7 +226,7 @@ new_group:
 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
                                                  struct btrfs_block_group_cache
                                                  *hint, u64 search_start,
-                                                 int data)
+                                                 int data, int owner)
 {
         struct btrfs_block_group_cache *cache[8];
         struct btrfs_block_group_cache *found_group = NULL;
@@ -207,6 +238,10 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
         int i;
         int ret;
         int full_search = 0;
+        int factor = 8;
+
+        if (!owner)
+                factor = 5;
 
         if (data)
                 radix = &info->block_group_data_radix;
@@ -219,14 +254,14 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
                 if (shint->data == data) {
                         used = btrfs_block_group_used(&shint->item);
                         if (used + shint->pinned <
-                            (shint->key.offset * 8) / 10) {
+                            (shint->key.offset * factor) / 10) {
                                 return shint;
                         }
                 }
         }
         if (hint && hint->data == data) {
                 used = btrfs_block_group_used(&hint->item);
-                if (used + hint->pinned < (hint->key.offset * 8) / 10) {
+                if (used + hint->pinned < (hint->key.offset * factor) / 10) {
                         return hint;
                 }
                 if (used >= (hint->key.offset * 8) / 10) {
@@ -261,7 +296,7 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
                                 cache[i]->key.offset;
                         used = btrfs_block_group_used(&cache[i]->item);
                         if (used + cache[i]->pinned <
-                            (cache[i]->key.offset * 8) / 10) {
+                            (cache[i]->key.offset * factor) / 10) {
                                 found_group = cache[i];
                                 goto found;
                         }
@@ -272,6 +307,7 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
                                                      BTRFS_BLOCK_GROUP_AVAIL);
                         }
                 }
+                cond_resched();
         }
         last = hint_last;
 again:
@@ -295,13 +331,16 @@ again:
                                                      BTRFS_BLOCK_GROUP_AVAIL);
                         }
                 }
+                cond_resched();
         }
         if (!full_search) {
+printk("find block group doing full search data %d start %Lu\n", data, search_start);
                 last = search_start;
                 full_search = 1;
                 goto again;
         }
         if (!found_group) {
+printk("find block group bailing to zero data %d\n", data);
                 ret = radix_tree_gang_lookup(radix,
                                              (void **)&found_group, 0, 1);
                 BUG_ON(ret != 1);
@@ -554,8 +593,8 @@ static int update_block_group(struct btrfs_trans_handle *trans,
                                                       blocknr + i);
                                 }
                         }
-                        if (old_val < (cache->key.offset * 6) / 10 &&
-                            old_val + num >= (cache->key.offset * 6) / 10) {
+                        if (old_val < (cache->key.offset * 5) / 10 &&
+                            old_val + num >= (cache->key.offset * 5) / 10) {
 printk("group %Lu now available\n", cache->key.objectid);
                                 radix_tree_tag_set(cache->radix,
                                                    cache->key.objectid +
@@ -842,6 +881,7 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         int level;
         struct btrfs_block_group_cache *block_group;
         int full_scan = 0;
+        u64 limit;
 
         path = btrfs_alloc_path();
         ins->flags = 0;
@@ -858,11 +898,11 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         if (search_start) {
                 block_group = lookup_block_group(info, search_start);
                 block_group = btrfs_find_block_group(root, block_group,
-                                                     search_start, data);
+                                                     search_start, data, 1);
         } else {
                 block_group = btrfs_find_block_group(root,
                                                      trans->block_group, 0,
-                                                     data);
+                                                     data, 1);
         }
 
 check_failed:
@@ -916,6 +956,12 @@ check_failed:
                                 info->extent_tree_prealloc_nr = 0;
                                 total_found = 0;
                         }
+                        if (start_found)
+                                limit = last_block +
+                                        block_group->key.offset / 2;
+                        else
+                                limit = search_start +
+                                        block_group->key.offset / 2;
                         ret = btrfs_next_leaf(root, path);
                         if (ret == 0)
                                 continue;
@@ -960,6 +1006,7 @@ check_failed:
                 }
 next:
                 path->slots[0]++;
+                cond_resched();
         }
         // FIXME -ENOSPC
 check_pending:
@@ -1049,7 +1096,8 @@ printk("doing full scan!\n");
         block_group = lookup_block_group(info, search_start);
         if (!full_scan)
                 block_group = btrfs_find_block_group(root, block_group,
-                                                     search_start, data);
+                                                     search_start, data, 0);
+        cond_resched();
         goto check_failed;
 
 error:
@@ -1102,7 +1150,7 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
          * in the correct block group.
          */
         if (data) {
-                ret = find_free_extent(trans, root, 0, search_start,
+                ret = find_free_extent(trans, root, 0, 0,
                                        search_end, &prealloc_key, 0);
                 if (ret) {
                         return ret;
@@ -1173,7 +1221,7 @@ struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
         struct buffer_head *buf;
 
         ret = btrfs_alloc_extent(trans, root, root->root_key.objectid,
-                                 1, 0, (unsigned long)-1, &ins, 0);
+                                 1, hint, (unsigned long)-1, &ins, 0);
         if (ret) {
                 BUG();
                 return NULL;