On Wed, Aug 03, 2011 at 03:06:55PM -0700, Simon Kirby wrote:
> I see Josef's 86d4a77ba3dc4ace238a0556541a41df2bd71d49 introduced the
> bitmaps list. I could try temporarily reverting this (some fixups needed)
> if anybody thinks my cache bouncing idea might be slightly possible.
I'll try the attached and see how the profile changes.
Simon-
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 6377713..99582f9 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2148,7 +2148,7 @@ again:
static noinline int
setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
struct btrfs_free_cluster *cluster,
- struct list_head *bitmaps, u64 offset, u64 bytes,
+ u64 offset, u64 bytes,
u64 min_bytes)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
@@ -2171,8 +2171,6 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
* extent entry.
*/
while (entry->bitmap) {
- if (list_empty(&entry->list))
- list_add_tail(&entry->list, bitmaps);
node = rb_next(&entry->offset_index);
if (!node)
return -ENOSPC;
@@ -2192,11 +2190,8 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
return -ENOSPC;
entry = rb_entry(node, struct btrfs_free_space, offset_index);
- if (entry->bitmap) {
- if (list_empty(&entry->list))
- list_add_tail(&entry->list, bitmaps);
+ if (entry->bitmap)
continue;
- }
/*
* we haven't filled the empty size and the window is
@@ -2252,7 +2247,7 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
static noinline int
setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
struct btrfs_free_cluster *cluster,
- struct list_head *bitmaps, u64 offset, u64 bytes,
+ u64 offset, u64 bytes,
u64 min_bytes)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
@@ -2263,39 +2258,10 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
if (ctl->total_bitmaps == 0)
return -ENOSPC;
- /*
- * First check our cached list of bitmaps and see if there is an entry
- * here that will work.
- */
- list_for_each_entry(entry, bitmaps, list) {
- if (entry->bytes < min_bytes)
- continue;
- ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
- bytes, min_bytes);
- if (!ret)
- return 0;
- }
-
- /*
- * If we do have entries on our list and we are here then we didn't find
- * anything, so go ahead and get the next entry after the last entry in
- * this list and start the search from there.
- */
- if (!list_empty(bitmaps)) {
- entry = list_entry(bitmaps->prev, struct btrfs_free_space,
- list);
- node = rb_next(&entry->offset_index);
- if (!node)
- return -ENOSPC;
- entry = rb_entry(node, struct btrfs_free_space, offset_index);
- goto search;
- }
-
entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1);
if (!entry)
return -ENOSPC;
-search:
node = &entry->offset_index;
do {
entry = rb_entry(node, struct btrfs_free_space, offset_index);
@@ -2326,8 +2292,6 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
u64 offset, u64 bytes, u64 empty_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
- struct list_head bitmaps;
- struct btrfs_free_space *entry, *tmp;
u64 min_bytes;
int ret;
@@ -2366,17 +2330,12 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
goto out;
}
- INIT_LIST_HEAD(&bitmaps);
- ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
+ ret = setup_cluster_no_bitmap(block_group, cluster, offset,
bytes, min_bytes);
if (ret)
- ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
+ ret = setup_cluster_bitmap(block_group, cluster,
offset, bytes, min_bytes);
- /* Clear our temporary list */
- list_for_each_entry_safe(entry, tmp, &bitmaps, list)
- list_del_init(&entry->list);
-
if (!ret) {
atomic_inc(&block_group->count);
list_add_tail(&cluster->block_group_list,
