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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 B040FC433DB for ; Sun, 28 Mar 2021 03:06:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 776C56198D for ; Sun, 28 Mar 2021 03:06:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230489AbhC1DF0 (ORCPT ); Sat, 27 Mar 2021 23:05:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230451AbhC1DFM (ORCPT ); Sat, 27 Mar 2021 23:05:12 -0400 Received: from mail-oi1-x22b.google.com (mail-oi1-x22b.google.com [IPv6:2607:f8b0:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AED77C0613B1 for ; Sat, 27 Mar 2021 20:05:11 -0700 (PDT) Received: by mail-oi1-x22b.google.com with SMTP id z15so9841323oic.8 for ; Sat, 27 Mar 2021 20:05:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=omnibond-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=APX4LnXlg+3kr85w1PEHFEdO/A+eUu4WKT9NHCRE6qg=; b=kGTx6ODuNVmBr7JV4L17yfvin2SbzEGB6u0QxbVSAKmK3dUilMeeMF+DMZ4Sd/yOn4 YDHqVNtdAqD9a4yDfe1Vqv2x/nrma30YYvHZVckSIsUjOEKT8Xsp3cKM2if2vc4+uXHD xVg8hOWJ1pFGjEVzNor6Y9coE4YC9oPlVuFb6+uxEfyZq7Fakp94w+/9IpIZIYjLn5GQ OOaghyxC+xWzj8eEfg/CxG8LaSnEiMpXOpX5VtsHdvVy5kOQQvcSLP5dVaMWrBf+wahh yTOO4Ov+OwipVPT0nNV/im1o8q9kTsctssAHpOFfOZUpg8Xq0ul/+trhbEAwCxdj6cAE JCUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=APX4LnXlg+3kr85w1PEHFEdO/A+eUu4WKT9NHCRE6qg=; b=U0YOTCpITQkd8kONIlma83AxyJldDhYRTX80FGY+LfU81wlYK3Kdp6MP1krQLkldVh Trl7nv3I5xmejZuaoJ3b3ItfNwnCqxdw8yeayNQkYxNjgRPRQSzkWgvXEYgG8FoOJSJB 7B8CtgKnlfH1Dzq3tesFc6e3rE6z8Sn04H9GTDabQ1fNba+NZMvYgdY/DQYFHfz3AqTd gTWTj0ylmoiQPq/kLCcohVi5QnbeIVE0hW4qnkYw97fJEBC8efY9l1HQtAXXB8h06pX9 /f2p4yADNuxSJ5F+7V+ioK1FfAqjzGXtJYesfNI7AIrxaGdT3YC0WDvzv+nvEe1XQW5w mhrQ== X-Gm-Message-State: AOAM531kBmUKKpXwX5vzrb2XYWQBQFj4rq+6QbTxWnPdyoTcBrbo03B7 4wBcs5+6d/5Dsq/p/XRsyu0hFWY100Ugd5pTo2eKSH4HZ+nqkwdT X-Google-Smtp-Source: ABdhPJx/qNSOBQSYsp9hF12yNdrNZRg5E+A/4mGx2r2CTFsAlVhotAQQUkz86yndMjiTdFYfZFhK/gpTZHWZ4ss7rK0= X-Received: by 2002:a54:4e08:: with SMTP id a8mr14971167oiy.135.1616900710908; Sat, 27 Mar 2021 20:05:10 -0700 (PDT) MIME-Version: 1.0 References: <20210327035019.GG1719932@casper.infradead.org> <20210201130800.GP308988@casper.infradead.org> <2884397.1616584210@warthog.procyon.org.uk> <1507388.1616833898@warthog.procyon.org.uk> <20210327135659.GH1719932@casper.infradead.org> <20210327155630.GJ1719932@casper.infradead.org> In-Reply-To: <20210327155630.GJ1719932@casper.infradead.org> From: Mike Marshall Date: Sat, 27 Mar 2021 23:04:59 -0400 Message-ID: Subject: Re: [RFC PATCH v2] implement orangefs_readahead To: Matthew Wilcox , Mike Marshall Cc: David Howells , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This seems OK... ? static void orangefs_readahead(struct readahead_control *rac) { loff_t offset; struct iov_iter iter; struct file *file = rac->file; struct inode *inode = file->f_mapping->host; struct xarray *i_pages; struct page *page; loff_t new_start = readahead_pos(rac); int ret; size_t new_len = 0; loff_t bytes_remaining = inode->i_size - readahead_pos(rac); loff_t pages_remaining = bytes_remaining / PAGE_SIZE; if (pages_remaining >= 1024) new_len = 4194304; else if (pages_remaining > readahead_count(rac)) new_len = bytes_remaining; if (new_len) readahead_expand(rac, new_start, new_len); offset = readahead_pos(rac); i_pages = &file->f_mapping->i_pages; iov_iter_xarray(&iter, READ, i_pages, offset, readahead_length(rac)); /* read in the pages. */ if ((ret = wait_for_direct_io(ORANGEFS_IO_READ, inode, &offset, &iter, readahead_length(rac), inode->i_size, NULL, NULL, file)) < 0) gossip_debug(GOSSIP_FILE_DEBUG, "%s: wait_for_direct_io failed. \n", __func__); else ret = 0; /* clean up. */ while ((page = readahead_page(rac))) { page_endio(page, false, ret); put_page(page); } } I need to go remember how to git send-email through the kernel.org email server, I apologize for the way gmail unformats my code, even in plain text mode... -Mike On Sat, Mar 27, 2021 at 11:56 AM Matthew Wilcox wrote: > > On Sat, Mar 27, 2021 at 11:40:08AM -0400, Mike Marshall wrote: > > int ret; > > > > loff_t new_start = readahead_index(rac) * PAGE_SIZE; > > That looks like readahead_pos() to me. > > > size_t new_len = 524288; > > readahead_expand(rac, new_start, new_len); > > > > npages = readahead_count(rac); > > offset = readahead_pos(rac); > > i_pages = &file->f_mapping->i_pages; > > > > iov_iter_xarray(&iter, READ, i_pages, offset, npages * PAGE_SIZE); > > readahead_length()? > > > /* read in the pages. */ > > ret = wait_for_direct_io(ORANGEFS_IO_READ, inode, &offset, &iter, > > npages * PAGE_SIZE, inode->i_size, NULL, NULL, file); > > > > /* clean up. */ > > while ((page = readahead_page(rac))) { > > page_endio(page, false, 0); > > put_page(page); > > } > > } > > What if wait_for_direct_io() returns an error? Shouldn't you be calling > > page_endio(page, false, ret) > > ? > > > On Sat, Mar 27, 2021 at 9:57 AM Matthew Wilcox wrote: > > > > > > On Sat, Mar 27, 2021 at 08:31:38AM +0000, David Howells wrote: > > > > However, in Mike's orangefs_readahead_cleanup(), he could replace: > > > > > > > > rcu_read_lock(); > > > > xas_for_each(&xas, page, last) { > > > > page_endio(page, false, 0); > > > > put_page(page); > > > > } > > > > rcu_read_unlock(); > > > > > > > > with: > > > > > > > > while ((page = readahead_page(ractl))) { > > > > page_endio(page, false, 0); > > > > put_page(page); > > > > } > > > > > > > > maybe? > > > > > > I'd rather see that than open-coded use of the XArray. It's mildly > > > slower, but given that we're talking about doing I/O, probably not enough > > > to care about.