Btrfs: More throttle tuning

* Make walk_down_tree wake up throttled tasks more often
* Make walk_down_tree call cond_resched during long loops
* As the size of the ref cache grows, wait longer in throttle
* Get rid of the reada code in walk_down_tree, the leaves don't get
  read anymore, thanks to the ref cache.

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

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d2d1cc87e8ad65da8c159946d6241117e0548f5e..da9dda4338a3247d10c9727f7674fc3e8924e685 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -188,13 +188,6 @@ static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
        btrfs_csum_final(crc, result);
 
        if (verify) {
-               int from_this_trans = 0;
-
-               if (root->fs_info->running_transaction &&
-                   btrfs_header_generation(buf) ==
-                   root->fs_info->running_transaction->transid)
-                       from_this_trans = 1;
-
                /* FIXME, this is not good */
                if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
                        u32 val;
@@ -203,11 +196,9 @@ static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 
                        read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
                        printk("btrfs: %s checksum verify failed on %llu "
-                              "wanted %X found %X from_this_trans %d "
-                              "level %d\n",
+                              "wanted %X found %X level %d\n",
                               root->fs_info->sb->s_id,
-                              buf->start, val, found, from_this_trans,
-                              btrfs_header_level(buf));
+                              buf->start, val, found, btrfs_header_level(buf));
                        return 1;
                }
        } else {

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 98a1c0faedae1c7c5e28cca62a7fcaab30a73878..1aeb695078b90406b1ef215b55317a2967ba2e82 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2369,6 +2369,11 @@ static int noinline drop_leaf_ref_no_cache(struct btrfs_trans_handle *trans,
                                leaf_owner, leaf_generation,
                                key.objectid, key.offset, 0);
                mutex_unlock(&root->fs_info->alloc_mutex);
+
+               atomic_inc(&root->fs_info->throttle_gen);
+               wake_up(&root->fs_info->transaction_throttle);
+               cond_resched();
+
                BUG_ON(ret);
        }
        return 0;
@@ -2389,6 +2394,11 @@ static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
                                        ref->owner, ref->generation,
                                        info->objectid, info->offset, 0);
                mutex_unlock(&root->fs_info->alloc_mutex);
+
+               atomic_inc(&root->fs_info->throttle_gen);
+               wake_up(&root->fs_info->transaction_throttle);
+               cond_resched();
+
                BUG_ON(ret);
                info++;
        }
@@ -2396,51 +2406,6 @@ static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
        return 0;
 }
 
-static void noinline reada_walk_down(struct btrfs_root *root,
-                                    struct extent_buffer *node,
-                                    int slot)
-{
-       u64 bytenr;
-       u64 last = 0;
-       u32 nritems;
-       u32 refs;
-       u32 blocksize;
-       int ret;
-       int i;
-       int level;
-       int skipped = 0;
-
-       nritems = btrfs_header_nritems(node);
-       level = btrfs_header_level(node);
-       if (level)
-               return;
-
-       for (i = slot; i < nritems && skipped < 32; i++) {
-               bytenr = btrfs_node_blockptr(node, i);
-               if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
-                            (last > bytenr && last - bytenr > 32 * 1024))) {
-                       skipped++;
-                       continue;
-               }
-               blocksize = btrfs_level_size(root, level - 1);
-               if (i != slot) {
-                       ret = lookup_extent_ref(NULL, root, bytenr,
-                                               blocksize, &refs);
-                       BUG_ON(ret);
-                       if (refs != 1) {
-                               skipped++;
-                               continue;
-                       }
-               }
-               ret = readahead_tree_block(root, bytenr, blocksize,
-                                          btrfs_node_ptr_generation(node, i));
-               last = bytenr + blocksize;
-               cond_resched();
-               if (ret)
-                       break;
-       }
-}
-
 int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
                              u32 *refs)
 {
@@ -2549,6 +2514,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
 
                        atomic_inc(&root->fs_info->throttle_gen);
                        wake_up(&root->fs_info->transaction_throttle);
+                       cond_resched();
 
                        continue;
                }
@@ -2578,8 +2544,6 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
                if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
                        free_extent_buffer(next);
 
-                       if (path->slots[*level] == 0)
-                               reada_walk_down(root, cur, path->slots[*level]);
                        next = read_tree_block(root, bytenr, blocksize,
                                               ptr_gen);
                        cond_resched();
@@ -2601,6 +2565,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
                path->nodes[*level-1] = next;
                *level = btrfs_header_level(next);
                path->slots[*level] = 0;
+               cond_resched();
        }
 out:
        WARN_ON(*level < 0);

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 9d84daf100086d113b6db4cd90a7c2b0022db42c..cf73342e8215a3d3458e319a89f80cecde32d119 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -210,7 +210,9 @@ static noinline int wait_for_commit(struct btrfs_root *root,
 static void throttle_on_drops(struct btrfs_root *root)
 {
        struct btrfs_fs_info *info = root->fs_info;
+       int harder_count = 0;
 
+harder:
        if (atomic_read(&info->throttles)) {
                DEFINE_WAIT(wait);
                int thr;
@@ -226,6 +228,19 @@ static void throttle_on_drops(struct btrfs_root *root)
                        schedule();
                        finish_wait(&info->transaction_throttle, &wait);
                } while (thr == atomic_read(&info->throttle_gen));
+               harder_count++;
+
+               if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
+                   harder_count < 2)
+                       goto harder;
+
+               if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
+                   harder_count < 10)
+                       goto harder;
+
+               if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
+                   harder_count < 20)
+                       goto harder;
        }
 }