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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8EA9AC77B73 for ; Wed, 24 May 2023 13:03:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235046AbjEXNDY (ORCPT ); Wed, 24 May 2023 09:03:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231562AbjEXNDK (ORCPT ); Wed, 24 May 2023 09:03:10 -0400 Received: from mail-oo1-xc33.google.com (mail-oo1-xc33.google.com [IPv6:2607:f8b0:4864:20::c33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39C6210F7 for ; Wed, 24 May 2023 06:02:31 -0700 (PDT) Received: by mail-oo1-xc33.google.com with SMTP id 006d021491bc7-541f4ee6f89so350717eaf.2 for ; Wed, 24 May 2023 06:02:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1684933350; x=1687525350; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=vdbwHbXRQumNFwA8UyQK25G7Ufvsj1W7ddnIDk9gS+g=; b=RWNTzZ6pSqiTOb6U4GdEjdR3jsFaECKKBvg55+It5Km3nJ80ftas/71muSloYpRrHI w7jxrxV5fnkBkKrVo8xErs49n/mk5ohg7EEneNUNWA05kO6Utdq3PL9tZu5cxyjIVQ/3 RSZ80KkuQrbNT+TGvkWTzn3QKWBTQWEBEj7h5m8aITfGvIbq/EPBrtQT2Ukru2/yzky6 EoOv+eftpfbVDcppwReDYblnp+ezvx3klhE9k6KUfVjZgabXMPg9JtLwxlPuuV/xeLed ao6kvcxntUhzf/tLMo5M41n2Po5dfD39T4RObzY4qocDoKCJm5oNoHhumJdcbtBCjvcw Eq+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684933350; x=1687525350; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=vdbwHbXRQumNFwA8UyQK25G7Ufvsj1W7ddnIDk9gS+g=; b=ddJ9K3zRFkxAbBXE2mSpmqWGf1EHAELB+UgTLqCB2Br8V7UdWVmEBVmt1l5iLCDabX NMCimeqMfuhtPmJY0ypxHqs3m5/cOsWdKCG+ZGhW3oIAAtedDA8Nckp7UQkNNFNCIhAr /ZctgZRE+6rVPZZ83QAaPgQloiHHXTr2AKHEanLqLgPKCwSsbOy8kS2uBs6g4gTsIq8/ XS8cpkbQNFJ4gTYJQxu3cwrJc6n06QsvsKE8qpdOxEGdHXGO8jVvvPn6sEy5jZs0wxu+ pQQGsIvLnlwgFzEhmunEK6apcArWLiVo6Pkm+m3MJaHI5xM0Y/dp21wIZWFKEOdbOXHk uvjQ== X-Gm-Message-State: AC+VfDz+uOb77tIfEmWroTtJYLsO3bq0dXPVZkHuFhrXUNFXxjr/i7LG XccsCU9EVPZwFy8eZ86Pb4MgwVAyeYKVrTedyDCF0A== X-Google-Smtp-Source: ACHHUZ7Lo5VynzbWayWaWvibO3+PR2emuxA0DtKTlRpZs5aLyrprk59Z6G1Ct6g/Gw7a0eEv4KsG8w5LIeBJx4QC3GM= X-Received: by 2002:a05:6358:910:b0:123:52c7:d5b3 with SMTP id r16-20020a056358091000b0012352c7d5b3mr98868rwi.12.1684933349696; Wed, 24 May 2023 06:02:29 -0700 (PDT) MIME-Version: 1.0 References: <20210911011819.12184-3-ricardo.neri-calderon@linux.intel.com> <163344312261.25758.16010066552550079330.tip-bot2@tip-bot2> <20230523105935.GN83892@hirez.programming.kicks-ass.net> In-Reply-To: <20230523105935.GN83892@hirez.programming.kicks-ass.net> From: Vincent Guittot Date: Wed, 24 May 2023 15:02:18 +0200 Message-ID: Subject: Re: [tip: sched/core] sched/topology: Introduce sched_group::flags To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, Ricardo Neri , "Joel Fernandes (Google)" , Len Brown , x86@kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 23 May 2023 at 12:59, Peter Zijlstra wrote: > > On Tue, Oct 05, 2021 at 02:12:02PM -0000, tip-bot2 for Ricardo Neri wrote: > > > index 4e8698e..c56faae 100644 > > --- a/kernel/sched/topology.c > > +++ b/kernel/sched/topology.c > > @@ -716,8 +716,20 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) > > tmp = sd; > > sd = sd->parent; > > destroy_sched_domain(tmp); > > - if (sd) > > + if (sd) { > > + struct sched_group *sg = sd->groups; > > + > > + /* > > + * sched groups hold the flags of the child sched > > + * domain for convenience. Clear such flags since > > + * the child is being destroyed. > > + */ > > + do { > > + sg->flags = 0; > > + } while (sg != sd->groups); > > > I happened to be reading this here code and aren't we missing: > > sg = sg->next; > > somewhere in that loop? Yes, I missed that. That being said, the only reason for sd to be degenerate is that there is only 1 group. Otherwise we will keep it and degenerate parents instead