From patchwork Tue Aug 13 09:13:23 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gao Xiang X-Patchwork-Id: 11091573 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D1B8214F7 for ; Tue, 13 Aug 2019 09:15:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C19CE285CB for ; Tue, 13 Aug 2019 09:15:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B57402864F; Tue, 13 Aug 2019 09:15:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1A55628640 for ; Tue, 13 Aug 2019 09:15:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728541AbfHMJOn (ORCPT ); Tue, 13 Aug 2019 05:14:43 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:51338 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728522AbfHMJOm (ORCPT ); Tue, 13 Aug 2019 05:14:42 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 19E2C830EBA6408DDB83; Tue, 13 Aug 2019 17:14:40 +0800 (CST) Received: from architecture4.huawei.com (10.140.130.215) by smtp.huawei.com (10.3.19.208) with Microsoft SMTP Server (TLS) id 14.3.439.0; Tue, 13 Aug 2019 17:14:31 +0800 From: Gao Xiang To: linux-fsdevel , LKML , Alexander Viro CC: Greg Kroah-Hartman , Andrew Morton , Stephen Rothwell , Theodore Ts'o , Pavel Machek , David Sterba , Amir Goldstein , Christoph Hellwig , "Darrick J . Wong" , "Dave Chinner" , Jaegeuk Kim , Jan Kara , Richard Weinberger , Linus Torvalds , , , Chao Yu , Miao Xie , Li Guifu , Fang Wei , Gao Xiang Subject: [PATCH v7 21/24] erofs: introduce LZ4 decompression inplace Date: Tue, 13 Aug 2019 17:13:23 +0800 Message-ID: <20190813091326.84652-22-gaoxiang25@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190813091326.84652-1-gaoxiang25@huawei.com> References: <20190813091326.84652-1-gaoxiang25@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.140.130.215] X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP compressed data will be usually loaded into last pages of the extent (the last page for 4k) for in-place decompression (more specifically, in-place IO), as ilustration below, start of compressed logical extent | end of this logical extent | | ______v___________________________v________ ... | page 6 | page 7 | page 8 | page 9 | ... |__________|__________|__________|__________| . ^ . ^ . |compressed| . | data | . . . |< dstsize >|| oend iend op ip Therefore, it's possible to do decompression inplace (thus no memcpy at all) if the margin is sufficient and safe enough [1], and it can be implemented only for fixed-size output compression compared with fixed-size input compression. No memcpy for most of in-place IO (about 99% of enwik9) after decompression inplace is implemented and sequential read will be improved of course (see the following patches for test results). [1] https://github.com/lz4/lz4/commit/b17f578a919b7e6b078cede2d52be29dd48c8e8c https://github.com/lz4/lz4/commit/5997e139f53169fa3a1c1b4418d2452a90b01602 Signed-off-by: Gao Xiang --- fs/erofs/decompressor.c | 36 ++++++++++++++++++++++++++++++++---- fs/erofs/erofs_fs.h | 2 +- 2 files changed, 33 insertions(+), 5 deletions(-) diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index 244afb29907d..1e9e1359e40c 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -15,6 +15,9 @@ #endif #define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1) +#ifndef LZ4_DECOMPRESS_INPLACE_MARGIN +#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32) +#endif struct z_erofs_decompressor { /* @@ -117,7 +120,7 @@ static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out) { unsigned int inputmargin, inlen; u8 *src; - bool copied; + bool copied, support_0padding; int ret; if (rq->inputsize > PAGE_SIZE) @@ -125,13 +128,38 @@ static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out) src = kmap_atomic(*rq->in); inputmargin = 0; + support_0padding = false; + + /* decompression inplace is only safe when 0padding is enabled */ + if (EROFS_SB(rq->sb)->requirements & EROFS_REQUIREMENT_LZ4_0PADDING) { + support_0padding = true; + + while (!src[inputmargin & ~PAGE_MASK]) + if (!(++inputmargin & ~PAGE_MASK)) + break; + + if (inputmargin >= rq->inputsize) { + kunmap_atomic(src); + return -EIO; + } + } copied = false; inlen = rq->inputsize - inputmargin; if (rq->inplace_io) { - src = generic_copy_inplace_data(rq, src, inputmargin); - inputmargin = 0; - copied = true; + const uint oend = (rq->pageofs_out + + rq->outputsize) & ~PAGE_MASK; + const uint nr = PAGE_ALIGN(rq->pageofs_out + + rq->outputsize) >> PAGE_SHIFT; + + if (rq->partial_decoding || !support_0padding || + rq->out[nr - 1] != rq->in[0] || + rq->inputsize - oend < + LZ4_DECOMPRESS_INPLACE_MARGIN(inlen)) { + src = generic_copy_inplace_data(rq, src, inputmargin); + inputmargin = 0; + copied = true; + } } ret = LZ4_decompress_safe_partial(src + inputmargin, out, diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h index 230fcba1099d..c0fb7d6ebfcb 100644 --- a/fs/erofs/erofs_fs.h +++ b/fs/erofs/erofs_fs.h @@ -17,7 +17,7 @@ * incompatible with this kernel version. */ #define EROFS_REQUIREMENT_LZ4_0PADDING 0x00000001 -#define EROFS_ALL_REQUIREMENTS 0 +#define EROFS_ALL_REQUIREMENTS EROFS_REQUIREMENT_LZ4_0PADDING struct erofs_super_block { /* 0 */__le32 magic; /* in the little endian */