Btrfs: make send's file extent item search more efficient

Instead of looking for a file extent item, process it, release the path
and do a btree search for the next file extent item, just process all
file extent items in a leaf without intermediate btree searches. This way
we save cpu and we're not blocking other tasks or affecting concurrency on
the btree, because send's paths use the commit root and skip btree node/leaf
locking.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Filipe David Borba Manana 2014-01-24 17:42:09 +00:00 committed by Chris Mason
parent 95def2ede1
commit 7fdd29d02e

View File

@ -4573,17 +4573,25 @@ static int process_all_extents(struct send_ctx *sctx)
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
@ -4596,8 +4604,7 @@ static int process_all_extents(struct send_ctx *sctx)
if (ret < 0)
goto out;
btrfs_release_path(path);
key.offset = found_key.offset + 1;
path->slots[0]++;
}
out: