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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 61E32C433DB for ; Sat, 27 Mar 2021 10:16:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31E7F61A05 for ; Sat, 27 Mar 2021 10:16:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231235AbhC0KQF (ORCPT ); Sat, 27 Mar 2021 06:16:05 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:30838 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229875AbhC0KQD (ORCPT ); Sat, 27 Mar 2021 06:16:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616840162; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XiLEqXCFPEAWMY3th6jHveSdHiLHcT6jJyaqLgZfeqA=; b=fPlshDRlx/14Sad5WS1gyd4sOuMh5RHSfeqplWL/teT1NcpA09Sn59qRR+xe0LR1ieR35a CzkK8lFGxPWFkp6ntzqOt2k4MFzdkvmd9VgplYlWBdSL3kkW5yHMMdmyyUPegcOtKnEpi7 8wU1Wv6WMeHFFSH9UzjTReZeLSrxZQE= Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-522-YWv4wHsaNdqqACs7jnGWog-1; Sat, 27 Mar 2021 06:16:00 -0400 X-MC-Unique: YWv4wHsaNdqqACs7jnGWog-1 Received: by mail-pf1-f198.google.com with SMTP id j7so7849084pfa.14 for ; Sat, 27 Mar 2021 03:16:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=XiLEqXCFPEAWMY3th6jHveSdHiLHcT6jJyaqLgZfeqA=; b=dNgOWHDSDn3X6bv/L7SnqYlQJvIViEF7fOvwVAFqogXiZttn/orxafh3i+jWhm2Qv6 fst2njbo+X8wX8fU4U1h48+l2F6v4m9BaAHaHq2iDImIvE2skpLXeh1HwPEoJAWiVXp9 Lfbj3ORNwmUn+a6FPM/4qW18IfetIBqRNLjIFVsI6RfCUv499fhfG0OwNEUkv095kn1e 1FjcodWnES0d78twKIrQ1Arq92nQn8yRPoKa63NqbQa+IxkumtILYekEbzIaWgAaboyN XrriwgbkLS+qjArv+LfgXM+8MS1uEIcHWzxXXJXnsMcrMLe1t9AgyxkRqravilq4QD4t v6+g== X-Gm-Message-State: AOAM530nVd4B4DmQ8auuaxi4vGgoPjKoUreELXJt0Ux0QYpfnOlRkP4A lGvcKtXtzwnA80pP0vHIoHk0JX6cz20u8lm5emfN6M/OKZqKPbeHGA4THx/uXZ+6js/BTbm84va D0ca4ev6cN/4OeCIOV3vj4Rqe X-Received: by 2002:a17:90a:6906:: with SMTP id r6mr18138214pjj.235.1616840159276; Sat, 27 Mar 2021 03:15:59 -0700 (PDT) X-Google-Smtp-Source: ABdhPJz0Hubov0I5CSfmFudM/r6ja59v9BcyPbQzN0J8z4Ny6nzZs996BKTtivIRigL6k31kOIGARA== X-Received: by 2002:a17:90a:6906:: with SMTP id r6mr18138194pjj.235.1616840159080; Sat, 27 Mar 2021 03:15:59 -0700 (PDT) Received: from xiangao.remote.csb ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id p1sm11465128pfn.22.2021.03.27.03.15.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 27 Mar 2021 03:15:58 -0700 (PDT) Date: Sat, 27 Mar 2021 18:15:48 +0800 From: Gao Xiang To: Chao Yu Cc: Gao Xiang , linux-erofs@lists.ozlabs.org, Chao Yu , LKML , Huang Jianan , Guo Weichao Subject: Re: [PATCH 2/4] erofs: support adjust lz4 history window size Message-ID: <20210327101548.GB2995728@xiangao.remote.csb> References: <20210327034936.12537-1-hsiangkao@aol.com> <20210327034936.12537-3-hsiangkao@aol.com> <8169edfd-de1d-e2de-4805-c7e3ce8d7502@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8169edfd-de1d-e2de-4805-c7e3ce8d7502@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chao, On Sat, Mar 27, 2021 at 05:34:33PM +0800, Chao Yu wrote: > On 2021/3/27 11:49, Gao Xiang wrote: > > From: Huang Jianan > > > > lz4 uses LZ4_DISTANCE_MAX to record history preservation. When > > using rolling decompression, a block with a higher compression > > ratio will cause a larger memory allocation (up to 64k). It may > > cause a large resource burden in extreme cases on devices with > > small memory and a large number of concurrent IOs. So appropriately > > reducing this value can improve performance. > > > > Decreasing this value will reduce the compression ratio (except > > when input_size > currently only supports 4k output, reducing this value will not > > significantly reduce the compression benefits. > > > > The maximum value of LZ4_DISTANCE_MAX defined by lz4 is 64k, and > > we can only reduce this value. For the old kernel, it just can't > > reduce the memory allocation during rolling decompression without > > affecting the decompression result. > > > > Signed-off-by: Huang Jianan > > Signed-off-by: Guo Weichao > > [ Gao Xiang: introduce struct erofs_sb_lz4_info for configurations. ] > > Signed-off-by: Gao Xiang > > --- > > fs/erofs/decompressor.c | 21 +++++++++++++++++---- > > fs/erofs/erofs_fs.h | 3 ++- > > fs/erofs/internal.h | 19 +++++++++++++++++++ > > fs/erofs/super.c | 4 +++- > > 4 files changed, 41 insertions(+), 6 deletions(-) > > > > diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c > > index 80e8871aef71..93411e9df9b6 100644 > > --- a/fs/erofs/decompressor.c > > +++ b/fs/erofs/decompressor.c > > @@ -28,6 +28,17 @@ struct z_erofs_decompressor { > > char *name; > > }; > > +int z_erofs_load_lz4_config(struct super_block *sb, > > + struct erofs_super_block *dsb) > > +{ > > + u16 distance = le16_to_cpu(dsb->lz4_max_distance); > > + > > + EROFS_SB(sb)->lz4.max_distance_pages = distance ? > > + DIV_ROUND_UP(distance, PAGE_SIZE) + 1 : > > + LZ4_MAX_DISTANCE_PAGES; > > + return 0; > > +} > > + > > static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq, > > struct list_head *pagepool) > > { > > @@ -36,6 +47,8 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq, > > struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL }; > > unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES, > > BITS_PER_LONG)] = { 0 }; > > + unsigned int lz4_max_distance_pages = > > + EROFS_SB(rq->sb)->lz4.max_distance_pages; > > void *kaddr = NULL; > > unsigned int i, j, top; > > @@ -44,14 +57,14 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq, > > struct page *const page = rq->out[i]; > > struct page *victim; > > - if (j >= LZ4_MAX_DISTANCE_PAGES) > > + if (j >= lz4_max_distance_pages) > > j = 0; > > /* 'valid' bounced can only be tested after a complete round */ > > if (test_bit(j, bounced)) { > > - DBG_BUGON(i < LZ4_MAX_DISTANCE_PAGES); > > - DBG_BUGON(top >= LZ4_MAX_DISTANCE_PAGES); > > - availables[top++] = rq->out[i - LZ4_MAX_DISTANCE_PAGES]; > > + DBG_BUGON(i < lz4_max_distance_pages); > > + DBG_BUGON(top >= lz4_max_distance_pages); > > + availables[top++] = rq->out[i - lz4_max_distance_pages]; > > } > > if (page) { > > diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h > > index 9ad1615f4474..b27d0e4e4ab5 100644 > > --- a/fs/erofs/erofs_fs.h > > +++ b/fs/erofs/erofs_fs.h > > @@ -39,7 +39,8 @@ struct erofs_super_block { > > __u8 uuid[16]; /* 128-bit uuid for volume */ > > __u8 volume_name[16]; /* volume name */ > > __le32 feature_incompat; > > - __u8 reserved2[44]; > > + __le16 lz4_max_distance; > > It missed to add comments, otherwise it looks good to me. > Yes, it needs some inline comment description, will update in the next version. > Reviewed-by: Chao Yu > Thanks for the review! Thanks, Gao Xiang > Thanks, >