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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 A8634C76191 for ; Mon, 15 Jul 2019 14:43:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 773ED20651 for ; Mon, 15 Jul 2019 14:43:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201786; bh=dWoLosDNIg5sdKZ9+ybWvRAOyFngUrfDTgHKbGOtVdw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xt8PeKGb4yY4c6AUQGwVu+U/31L20A889RrExunR+NqQorpVf31phRq95avBjFWDu LcUalBJ7nWE8V65fidUuyz1+kKcM1cjabnaspKmPvu66XsL6cAp/mgl+gDCsIkNhxi bLH/M+VVAl497ALOiFLU1QnQ57erFlvArq6Gycs8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392232AbfGOOjC (ORCPT ); Mon, 15 Jul 2019 10:39:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:37904 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403788AbfGOOjB (ORCPT ); Mon, 15 Jul 2019 10:39:01 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6604120896; Mon, 15 Jul 2019 14:38:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201540; bh=dWoLosDNIg5sdKZ9+ybWvRAOyFngUrfDTgHKbGOtVdw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZTpGA9EjmLvvC7OCt+1AtsSaQILfea+LCVO6y4qiATBv74QSnU5BEOW6827n/rtVU t23hCaXighezhjWtCERCa+VKrw/XY9fJ0k6NK6eizQOygHmqrIpWLJ0IEDHlQe4jhs FyvQiCMQAhZ/F+/hgAowT3ld/EtQqC5A2WRbuUvU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tejun Heo , Jan Kara , Jens Axboe , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 38/73] blkcg, writeback: dead memcgs shouldn't contribute to writeback ownership arbitration Date: Mon, 15 Jul 2019 10:35:54 -0400 Message-Id: <20190715143629.10893-38-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715143629.10893-1-sashal@kernel.org> References: <20190715143629.10893-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Tejun Heo [ Upstream commit 6631142229005e1b1c311a09efe9fb3cfdac8559 ] wbc_account_io() collects information on cgroup ownership of writeback pages to determine which cgroup should own the inode. Pages can stay associated with dead memcgs but we want to avoid attributing IOs to dead blkcgs as much as possible as the association is likely to be stale. However, currently, pages associated with dead memcgs contribute to the accounting delaying and/or confusing the arbitration. Fix it by ignoring pages associated with dead memcgs. Signed-off-by: Tejun Heo Cc: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/fs-writeback.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 8b93d4b98428..baaed9369ab4 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -721,6 +721,7 @@ void wbc_detach_inode(struct writeback_control *wbc) void wbc_account_io(struct writeback_control *wbc, struct page *page, size_t bytes) { + struct cgroup_subsys_state *css; int id; /* @@ -732,7 +733,12 @@ void wbc_account_io(struct writeback_control *wbc, struct page *page, if (!wbc->wb) return; - id = mem_cgroup_css_from_page(page)->id; + css = mem_cgroup_css_from_page(page); + /* dead cgroups shouldn't contribute to inode ownership arbitration */ + if (!(css->flags & CSS_ONLINE)) + return; + + id = css->id; if (id == wbc->wb_id) { wbc->wb_bytes += bytes; -- 2.20.1