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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4A66C433F5 for ; Mon, 16 May 2022 11:04:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4847C6B0072; Mon, 16 May 2022 07:04:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 433236B0073; Mon, 16 May 2022 07:04:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2FBD56B0075; Mon, 16 May 2022 07:04:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 1DFCA6B0072 for ; Mon, 16 May 2022 07:04:36 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id F251A1419 for ; Mon, 16 May 2022 11:04:35 +0000 (UTC) X-FDA: 79471322910.03.4798984 Received: from mail-vs1-f50.google.com (mail-vs1-f50.google.com [209.85.217.50]) by imf10.hostedemail.com (Postfix) with ESMTP id A9D1DC00A3 for ; Mon, 16 May 2022 11:04:07 +0000 (UTC) Received: by mail-vs1-f50.google.com with SMTP id w124so15091475vsb.8 for ; Mon, 16 May 2022 04:04:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=vkeDkFkYpkmRJ364RgcYqVHpDHCVzTSeOQ89Cq0MtS8=; b=S5+KmO4aosUfRV541We6wTd6sve2C2jxofS550PddoyoaVJyjTlteA1h6W6VFPgoyA HCgQ7fPNUxmrLAVaKGHu9qXG6jQkUitCp/l3whsMngT4ONWPKuQhQxL493inaHD5bLee t5wT7tF+V/bEUVcxyxY0dirsJhDND54dcGfzA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=vkeDkFkYpkmRJ364RgcYqVHpDHCVzTSeOQ89Cq0MtS8=; b=gtaU/MTwZC7leqwGfHo5dyRGwMuZN7fTMeWXPYro8tu710EaQcIK6UjDYGnc+Qe6m9 AR3I59zzgMnMli7AwQItpVgAS5QBYR5G9jZz0QZQ0n4+WWAUQ7qL67BX8CZYHgdCfgS7 JN1eMIfg1nOL2VOONRF9QBfgRFu5qqJgxpOfX4kHc4M7Zl+JASNRmAGfnofbEhZ4i/ai Vbl3UiBQXlSfwAz2AjVmw2N04AXTNb3eeIv6e0OS9/3UYd/J9s4xT0qL6RM7gaLmPiOr z2IvyzeL2Q4uqKBSyAH8TiyG2wQK1AdTHSCPuZkkKtHPcMJixPKUjvobIq72Kd8nAjJU rQBg== X-Gm-Message-State: AOAM532xeK8QKsV6O8WWMYuG8N69NJfngX1vdu1lEDZksV3WST0+VggX P7vS2pncOZzgayGvrG5dv2laQ0y9FivDf/qhAl9sS0Cce7kdbQ== X-Google-Smtp-Source: ABdhPJy/t2EK0wj7DIUgHQJxkAvMKiBtEuItKuf9ivBIXzsz1re04fcHg/GAOshdJcGvYzYj1/2wgalPsfQJVHRkehM= X-Received: by 2002:a05:6102:558f:b0:32d:7901:edcc with SMTP id dc15-20020a056102558f00b0032d7901edccmr6119228vsb.80.1652699074738; Mon, 16 May 2022 04:04:34 -0700 (PDT) MIME-Version: 1.0 References: <20220516105100.1412740-1-hsinyi@chromium.org> <20220516105100.1412740-3-hsinyi@chromium.org> In-Reply-To: <20220516105100.1412740-3-hsinyi@chromium.org> From: Hsin-Yi Wang Date: Mon, 16 May 2022 19:04:08 +0800 Message-ID: Subject: Re: [PATCH 2/2] squashfs: implement readahead To: Phillip Lougher , Matthew Wilcox , Xiongwei Song Cc: Zheng Liang , Zhang Yi , Hou Tao , Miao Xie , Andrew Morton , "linux-mm @ kvack . org" , "squashfs-devel @ lists . sourceforge . net" , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: querqwhzdwcx4s55n1c1kstyst6h6ncn X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: A9D1DC00A3 X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=S5+KmO4a; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf10.hostedemail.com: domain of hsinyi@chromium.org designates 209.85.217.50 as permitted sender) smtp.mailfrom=hsinyi@chromium.org X-HE-Tag: 1652699047-867057 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, May 16, 2022 at 6:51 PM Hsin-Yi Wang wrote: > > Implement readahead callback for squashfs. It will read datablocks > which cover pages in readahead request. For a few cases it will > not mark page as uptodate, including: > - file end is 0. > - zero filled blocks. > - current batch of pages isn't in the same datablock or not enough in a > datablock. > Otherwise pages will be marked as uptodate. The unhandled pages will be > updated by readpage later. > Suggested-by: Matthew Wilcox > Signed-off-by: Hsin-Yi Wang > --- > Note that this patch was not formally sent to the list before. It's > attached to email thread for discussion as it's still under development. > > - v1: > The patch outline was suggested by Matthew. It went through a few > reviews by Matthew offline. > > - v2: > https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#m442435c149d411c5c9d8019cff5915419b04bf10 > This is a resend of v1. > > - v3: > https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#m55a709e6ba5ec59fe95323a67a7f3d6b1953e470 > Fix page actor size to avoid a crash from squashfs_decompress(). > Suggested by Phillip Lougher[1] > [1] https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#m687f82debb7667ff31982a05aef3eba081eb5039 > > - v4: > https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#mf93267690ec2e841dade6a494fe72c84b61328d9 > Fix to free page after used. Suggested by Xiongwei Song[2] > Refactor the skip page logic to possible improve the performance. > Suggested by Phillip Lougher[3] > [2] https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#m0e7b33d167b1ef0eb39b9f41c32ed3f80dfced18 > [3] https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#m1e0a8f8e4a98d79d14c81b66e197b6dc0a3b77a1 > --- > fs/squashfs/file.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 77 insertions(+) > > diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c > index a8e495d8eb86..91dfec792f4c 100644 > --- a/fs/squashfs/file.c > +++ b/fs/squashfs/file.c > @@ -39,6 +39,7 @@ > #include "squashfs_fs_sb.h" > #include "squashfs_fs_i.h" > #include "squashfs.h" > +#include "page_actor.h" > > /* > * Locate cache slot in range [offset, index] for specified inode. If > @@ -495,7 +496,83 @@ static int squashfs_read_folio(struct file *file, struct folio *folio) > return 0; > } > > +static void squashfs_readahead(struct readahead_control *ractl) > +{ > + struct inode *inode = ractl->mapping->host; > + struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; > + size_t mask = (1UL << msblk->block_log) - 1; > + size_t shift = msblk->block_log - PAGE_SHIFT; > + loff_t req_end = readahead_pos(ractl) + readahead_length(ractl); > + loff_t start = readahead_pos(ractl) &~ mask; > + size_t len = readahead_length(ractl) + readahead_pos(ractl) - start; > + struct squashfs_page_actor *actor; > + unsigned int nr_pages = 0; > + struct page **pages; > + u64 block = 0; > + int bsize, res, i, index; > + int file_end = i_size_read(inode) >> msblk->block_log; > + unsigned int max_pages = 1UL << shift; > + > + readahead_expand(ractl, start, (len | mask) + 1); > + > + if (readahead_pos(ractl) + readahead_length(ractl) < req_end || > + file_end == 0) > + return; > + > + pages = kmalloc_array(max_pages, sizeof(void *), GFP_KERNEL); > + if (!pages) > + return; > + > + actor = squashfs_page_actor_init_special(pages, max_pages, 0); > + if (!actor) > + goto out; > + > + for (;;) { > + nr_pages = __readahead_batch(ractl, pages, max_pages); > + if (!nr_pages) > + break; > + > + if (readahead_pos(ractl) >= i_size_read(inode) || > + nr_pages < max_pages) > + goto skip_pages; > + > + index = pages[0]->index >> shift; > + if ((pages[nr_pages - 1]->index >> shift) != index) > + goto skip_pages; > + > + bsize = read_blocklist(inode, index, &block); > + if (bsize == 0) > + goto skip_pages; > + > + res = squashfs_read_data(inode->i_sb, block, bsize, NULL, > + actor); > + > + if (res >= 0) > + for (i = 0; i < nr_pages; i++) > + SetPageUptodate(pages[i]); > + > + for (i = 0; i < nr_pages; i++) { > + unlock_page(pages[i]); > + put_page(pages[i]); > + } > + } > + > + kfree(actor); > + kfree(pages); > + return; > + > +skip_pages: > + for (i = 0; i < nr_pages; i++) { > + unlock_page(pages[i]); > + put_page(pages[i]); > + } > + > + kfree(actor); > +out: > + kfree(pages); > +} > > const struct address_space_operations squashfs_aops = { > .read_folio = squashfs_read_folio > + .readahead = squashfs_readahead > }; > -- > 2.36.0.550.gb090851708-goog >