Moving the Z_FINISH into the loop also means we don't have to force a
flush after every input page to guarantee that there won't be more than 4
KiB to write at the end. This patch lets zlib decide when to flush
buffer, which offers a very moderate space savings (on my system, my 400MB
test logfile goes from an 11.9% compression ratio to 11.2%, which is
nothing to write home about) and might offer a similarly-slight
performance boost.
Since the end result is still a valid zlib stream, it is completely
backwards-compatible with the existing method.
Signed-off-by: Danielle Church <dchurch@xxxxxxxxxxxxxxx>
---
fs/btrfs/zlib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 1dc0455..df7d957 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -89,7 +89,7 @@ static int zlib_compress_pages(struct list_head *ws,
struct page *in_page = NULL;
struct page *out_page = NULL;
unsigned long bytes_left;
- int deflate_flush = Z_SYNC_FLUSH;
+ int deflate_flush = Z_NO_FLUSH;
*out_pages = 0;
*total_out = 0;
--
2.2.1
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