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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 25006C43387 for ; Thu, 3 Jan 2019 08:50:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7E1320883 for ; Thu, 3 Jan 2019 08:50:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730325AbfACIuM (ORCPT ); Thu, 3 Jan 2019 03:50:12 -0500 Received: from mx2.suse.de ([195.135.220.15]:60106 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726702AbfACIuK (ORCPT ); Thu, 3 Jan 2019 03:50:10 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E8D0FAEBC for ; Thu, 3 Jan 2019 08:50:08 +0000 (UTC) From: Nikolay Borisov To: linux-btrfs@vger.kernel.org Cc: Nikolay Borisov Subject: [PATCH 7/7] btrfs: Refactor shrink_delalloc Date: Thu, 3 Jan 2019 10:50:05 +0200 Message-Id: <20190103085005.32053-8-nborisov@suse.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190103085005.32053-1-nborisov@suse.com> References: <20190103085005.32053-1-nborisov@suse.com> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Add a couple of comments regarding the logic flow in shrink_delalloc. Then, cease using max_reclaim as a temporary variable when calculating nr_pages. Finally give max_reclaim a more becoming name, which uneqivocally shows at what this variable really holds. No functional changes. Signed-off-by: Nikolay Borisov --- fs/btrfs/extent-tree.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index b15afeae16df..615441f4d458 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4743,7 +4743,7 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim, struct btrfs_space_info *space_info; struct btrfs_trans_handle *trans; u64 delalloc_bytes; - u64 max_reclaim; + u64 async_pages; u64 items; long time_left; unsigned long nr_pages; @@ -4768,25 +4768,36 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim, loops = 0; while (delalloc_bytes && loops < 3) { - max_reclaim = min(delalloc_bytes, to_reclaim); - nr_pages = max_reclaim >> PAGE_SHIFT; + nr_pages = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT; + + /* + * Triggers inode writeback for up to nr_pages. This will invoke + * ->writepages callback and trigger delalloc filling + * (btrfs_run_delalloc_range()). + */ btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items); + /* - * We need to wait for the async pages to actually start before - * we do anything. + * We need to wait for the compressed pages to start before + * we continue. */ - max_reclaim = atomic_read(&fs_info->async_delalloc_pages); - if (!max_reclaim) + async_pages = atomic_read(&fs_info->async_delalloc_pages); + if (!async_pages) goto skip_async; - if (max_reclaim <= nr_pages) - max_reclaim = 0; + /* + * Calculate how many compressed pages we want to be written + * before we continue. I.e if there are more async pages than we + * require wait_event will wait until nr_pages are written. + */ + if (async_pages <= nr_pages) + async_pages = 0; else - max_reclaim -= nr_pages; + async_pages -= nr_pages; wait_event(fs_info->async_submit_wait, atomic_read(&fs_info->async_delalloc_pages) <= - (int)max_reclaim); + (int)async_pages); skip_async: spin_lock(&space_info->lock); if (list_empty(&space_info->tickets) && -- 2.17.1