From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934490AbbI2QtV (ORCPT ); Tue, 29 Sep 2015 12:49:21 -0400 Received: from mail-yk0-f179.google.com ([209.85.160.179]:33969 "EHLO mail-yk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935148AbbI2QsH (ORCPT ); Tue, 29 Sep 2015 12:48:07 -0400 From: Tejun Heo To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, tytso@mit.edu, dedekind1@gmail.com, decui@microsoft.com, kernel-team@fb.com, Tejun Heo Subject: [PATCH 4/5] writeback: memcg dirty_throttle_control should be initialized with wb->memcg_completions Date: Tue, 29 Sep 2015 12:47:53 -0400 Message-Id: <1443545274-18787-5-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1443545274-18787-1-git-send-email-tj@kernel.org> References: <1443545274-18787-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org MDTC_INIT() is used to initialize dirty_throttle_control for memcg domains. It used DTC_INIT_COMMON() to initialized mdtc->wb and ->wb_completions which is incorrect as DTC_INIT_COMMON() sets the latter to wb->completions instead of wb->memcg_completions. This can lead to wildly incorrect results when calculating the proportion of dirty memory the memcg domain should get. Remove DTC_INIT_COMMON() and update MDTC_INIT() to initialize mdtc->wb_completions to wb->memcg_completions. Signed-off-by: Tejun Heo Fixes: c2aa723a6093 ("writeback: implement memcg writeback domain based throttling") --- mm/page-writeback.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 0f1a94e..56c0bff 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -145,9 +145,6 @@ struct dirty_throttle_control { unsigned long pos_ratio; }; -#define DTC_INIT_COMMON(__wb) .wb = (__wb), \ - .wb_completions = &(__wb)->completions - /* * Length of period for aging writeout fractions of bdis. This is an * arbitrarily chosen number. The longer the period, the slower fractions will @@ -157,12 +154,16 @@ struct dirty_throttle_control { #ifdef CONFIG_CGROUP_WRITEBACK -#define GDTC_INIT(__wb) .dom = &global_wb_domain, \ - DTC_INIT_COMMON(__wb) +#define GDTC_INIT(__wb) .wb = (__wb), \ + .dom = &global_wb_domain, \ + .wb_completions = &(__wb)->completions + #define GDTC_INIT_NO_WB .dom = &global_wb_domain -#define MDTC_INIT(__wb, __gdtc) .dom = mem_cgroup_wb_domain(__wb), \ - .gdtc = __gdtc, \ - DTC_INIT_COMMON(__wb) + +#define MDTC_INIT(__wb, __gdtc) .wb = (__wb), \ + .dom = mem_cgroup_wb_domain(__wb), \ + .wb_completions = &(__wb)->memcg_completions, \ + .gdtc = __gdtc static bool mdtc_valid(struct dirty_throttle_control *dtc) { @@ -213,7 +214,8 @@ static void wb_min_max_ratio(struct bdi_writeback *wb, #else /* CONFIG_CGROUP_WRITEBACK */ -#define GDTC_INIT(__wb) DTC_INIT_COMMON(__wb) +#define GDTC_INIT(__wb) .wb = (__wb), \ + .wb_completions = &(__wb)->completions #define GDTC_INIT_NO_WB #define MDTC_INIT(__wb, __gdtc) -- 2.4.3