From 3067a8d931ab5cdf4cb269fa6f66ebe0a7c1859d Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Sat, 9 May 2020 15:01:04 +0800 Subject: [PATCH] f2fs: compress: let lz4 compressor handle output buffer budget properly Commonly, in order to handle lz4 worst compress case, caller should allocate buffer with size of LZ4_compressBound(inputsize) for target compressed data storing, however in this case, if caller didn't allocate enough space, lz4 compressor still can handle output buffer budget properly, and end up compressing when left space in output buffer is not enough. So we don't have to allocate buffer with size for worst case, then we can avoid 2 * 4KB size intermediate buffer allocation when log_cluster_size is 2, and avoid unnecessary compressing work of compressor if we can not save at least 4KB space. Suggested-by: Daeho Jeong Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/compress.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index b726aad898de..fd7cdb814def 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -228,7 +228,12 @@ static int lz4_init_compress_ctx(struct compress_ctx *cc) if (!cc->private) return -ENOMEM; - cc->clen = LZ4_compressBound(PAGE_SIZE << cc->log_cluster_size); + /* + * we do not change cc->clen to LZ4_compressBound(inputsize) to + * adapt worst compress case, because lz4 compressor can handle + * output budget properly. + */ + cc->clen = cc->rlen - PAGE_SIZE - COMPRESS_HEADER_SIZE; return 0; } @@ -244,11 +249,9 @@ static int lz4_compress_pages(struct compress_ctx *cc) len = LZ4_compress_default(cc->rbuf, cc->cbuf->cdata, cc->rlen, cc->clen, cc->private); - if (!len) { - printk_ratelimited("%sF2FS-fs (%s): lz4 compress failed\n", - KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id); - return -EIO; - } + if (!len) + return -EAGAIN; + cc->clen = len; return 0; }