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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 448D2C433B4 for ; Mon, 17 May 2021 16:42:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26B1A61059 for ; Mon, 17 May 2021 16:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243434AbhEQQny (ORCPT ); Mon, 17 May 2021 12:43:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242061AbhEQQnm (ORCPT ); Mon, 17 May 2021 12:43:42 -0400 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE796C0612AB for ; Mon, 17 May 2021 08:53:23 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id 27so3643845pgy.3 for ; Mon, 17 May 2021 08:53:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=F2QBpAAF++uWH6CxS2YX3b9qpY1ggeZ6Y1tZ4KY25HY=; b=jAPqhJq6lwJYhWZL3sGNCzW5kQwuxbRa7eapGo0FDnsbS9I4G4jD55IAqlrFcWTSId OB/lf7hTKTWzuTc3tBDEOUHHzILFsEplNAJM6ZJfuQ5zfQK5wd0uOY1lNJWPg2DYHu8W aBhmPKW3ZDkV4iSO3VPB5/Au+tDdTKsf+IDSCq2mxcbWATOII374ANzAl5/w2Web+Hbm ZohnJIsmDY2cjIb6uSdvEq6pTU/ZZBCXT9qgUuAmLInU8H0R7TiyxWBgQHtcziXsSbsf SDDXhEDLxOLOKHrpxGNRv/RYCN+KDDb7sGO0y/vb80kjrIaAm6A4JJlzJUx8mHaM2RlR t3eA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=F2QBpAAF++uWH6CxS2YX3b9qpY1ggeZ6Y1tZ4KY25HY=; b=FRzFx4GVC88EpAGIKZ2/378wV95OBCAF+Uy3Es+xtAIqGB5sD6H9yLjr3M0lf+TsMI 5c/X7D3jtfza05LFKLopcazyaeY4nWjPrw0YII/EhvkVwvpLcSJrRu42bp4JP+XCEiQh DyJeK5pr0wLTM34kZpG5Ku89hedx8A+GirJdKGwvMqk8vT69EKbPMpjvtCxPwdTzEiAS oy8xBaBa00y0VVazFxeotAP9kt/pzgPHyAHpXSx1qQ7hb4cmblBIrZabgS+Cbj1nGzhK W9hkkMMuryOZLlQtjsxnZXeS/XGANtcylJNK17/6t3HveZuvEb2BbzNpw75KZafR9YPT Ggxw== X-Gm-Message-State: AOAM530DGFxOiaZV1eYDdAIyd+WKchu5LsO0riuqachWrc1Ub5v+JA9P 0/WygMmhqYwCy66lJdAkC/k= X-Google-Smtp-Source: ABdhPJzU6fIFr1C7AGK5qoUaBq4gRzKSFRfaOhpc8WHiSr/G1AETnQfD/J2QXHrZE2JHH1y3edl2mA== X-Received: by 2002:a62:1a4b:0:b029:24e:ba53:aaa4 with SMTP id a72-20020a621a4b0000b029024eba53aaa4mr304822pfa.63.1621266803306; Mon, 17 May 2021 08:53:23 -0700 (PDT) Received: from wuchi.mioffice.cn ([2408:8607:1b00:a:4a4d:7eff:feb5:2e68]) by smtp.gmail.com with ESMTPSA id jz7sm2190306pjb.32.2021.05.17.08.53.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 May 2021 08:53:22 -0700 (PDT) From: Chi Wu To: akpm@linux-foundation.org Cc: jack@suse.cz, linux-kernel@vger.kernel.org, tan.hu@zte.com.cn, Chi Wu Subject: [PATCH] lib/flex_proportions.c: Use abs() when percpu_counter is negative. Date: Mon, 17 May 2021 23:53:06 +0800 Message-Id: <20210517155306.11113-1-wuchi.zero@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The value of percpu_counter_read() may become negative after running percpu_counter_sum() in fprop_reflect_period_percpu(). The value of variable 'num' will be zero in fprop_fraction_percpu() when using percpu_counter_read_positive(), but if using the abs of percpu_counter_read() will be close to the correct value. Signed-off-by: Chi Wu --- lib/flex_proportions.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/lib/flex_proportions.c b/lib/flex_proportions.c index 451543937524..3ac79ca2c441 100644 --- a/lib/flex_proportions.c +++ b/lib/flex_proportions.c @@ -147,7 +147,7 @@ void fprop_fraction_single(struct fprop_global *p, seq = read_seqcount_begin(&p->sequence); fprop_reflect_period_single(p, pl); num = pl->events; - den = percpu_counter_read_positive(&p->events); + den = abs(percpu_counter_read(&p->events)); } while (read_seqcount_retry(&p->sequence, seq)); /* @@ -209,7 +209,7 @@ static void fprop_reflect_period_percpu(struct fprop_global *p, val = percpu_counter_sum(&pl->events); percpu_counter_add_batch(&pl->events, - -val + (val >> (period-pl->period)), PROP_BATCH); + -val + (val >> (period - pl->period)), PROP_BATCH); } else percpu_counter_set(&pl->events, 0); pl->period = period; @@ -234,8 +234,8 @@ void fprop_fraction_percpu(struct fprop_global *p, do { seq = read_seqcount_begin(&p->sequence); fprop_reflect_period_percpu(p, pl); - num = percpu_counter_read_positive(&pl->events); - den = percpu_counter_read_positive(&p->events); + num = abs(percpu_counter_read(&pl->events)); + den = abs(percpu_counter_read(&p->events)); } while (read_seqcount_retry(&p->sequence, seq)); /* -- 2.17.1