From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D85BC38A2A for ; Fri, 8 May 2020 09:47:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 425AC208D6 for ; Fri, 8 May 2020 09:47:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727082AbgEHJrU (ORCPT ); Fri, 8 May 2020 05:47:20 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:4351 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725815AbgEHJrU (ORCPT ); Fri, 8 May 2020 05:47:20 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 5F697D520C64F886C4E0; Fri, 8 May 2020 17:47:18 +0800 (CST) Received: from szvp000203569.huawei.com (10.120.216.130) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.487.0; Fri, 8 May 2020 17:47:11 +0800 From: Chao Yu To: CC: , , , Chao Yu Subject: [PATCH] f2fs: compress: allow lz4 to compress data partially Date: Fri, 8 May 2020 17:47:09 +0800 Message-ID: <20200508094709.40048-1-yuchao0@huawei.com> X-Mailer: git-send-email 2.18.0.rc1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.120.216.130] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For lz4 worst compress case, caller should allocate buffer with size of LZ4_compressBound(inputsize) for target compressed data storing. However lz4 supports partial data compression, so we can get rid of output buffer size limitation now, 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 --- 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 5e4947250262..23825f559bcf 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 algorithm supports partial + * compression. + */ + 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; } -- 2.18.0.rc1