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authorDavid Sterba2020-04-29 23:23:37 +0200
committerDavid Sterba2020-05-25 11:25:33 +0200
commit5cd17f343bd1c47dc673260fa2973abc14ecc549 (patch)
tree4dc319fad6bf754e73054a0fcd529d18ad203549 /fs/btrfs
parentce7afe8782a5293edbf4bc2165ac4a866ed430db (diff)
btrfs: speed up and simplify generic_bin_search
The bin search jumps over the extent buffer item keys, comparing directly the bytes if the key is in one page, or storing it in a temporary buffer in case it spans two pages. The mapping start and length are obtained from map_private_extent_buffer, which is heavy weight compared to what we need. We know the key size and can find out the eb page in a simple way. For keys spanning two pages the fallback read_extent_buffer is used. The temporary variables are reduced and moved to the scope of use. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/ctree.c43
1 files changed, 15 insertions, 28 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 6dbeb23c59ec..746dec22f250 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1668,15 +1668,8 @@ static noinline int generic_bin_search(struct extent_buffer *eb,
{
int low = 0;
int high = max;
- int mid;
int ret;
- struct btrfs_disk_key *tmp = NULL;
- struct btrfs_disk_key unaligned;
- unsigned long offset;
- char *kaddr = NULL;
- unsigned long map_start = 0;
- unsigned long map_len = 0;
- int err;
+ const int key_size = sizeof(struct btrfs_disk_key);
if (low > high) {
btrfs_err(eb->fs_info,
@@ -1687,32 +1680,26 @@ static noinline int generic_bin_search(struct extent_buffer *eb,
}
while (low < high) {
+ unsigned long oip;
+ unsigned long offset;
+ struct btrfs_disk_key *tmp;
+ struct btrfs_disk_key unaligned;
+ int mid;
+
mid = (low + high) / 2;
offset = p + mid * item_size;
+ oip = offset_in_page(offset);
- if (!kaddr || offset < map_start ||
- (offset + sizeof(struct btrfs_disk_key)) >
- map_start + map_len) {
-
- err = map_private_extent_buffer(eb, offset,
- sizeof(struct btrfs_disk_key),
- &kaddr, &map_start, &map_len);
-
- if (!err) {
- tmp = (struct btrfs_disk_key *)(kaddr + offset -
- map_start);
- } else if (err == 1) {
- read_extent_buffer(eb, &unaligned,
- offset, sizeof(unaligned));
- tmp = &unaligned;
- } else {
- return err;
- }
+ if (oip + key_size <= PAGE_SIZE) {
+ const unsigned long idx = offset >> PAGE_SHIFT;
+ char *kaddr = page_address(eb->pages[idx]);
+ tmp = (struct btrfs_disk_key *)(kaddr + oip);
} else {
- tmp = (struct btrfs_disk_key *)(kaddr + offset -
- map_start);
+ read_extent_buffer(eb, &unaligned, offset, key_size);
+ tmp = &unaligned;
}
+
ret = comp_keys(tmp, key);
if (ret < 0)