From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98CD721B195 for ; Mon, 12 Jan 2026 02:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768185957; cv=none; b=bRjh1BphxRapJn1QuUH5mHgE6HWOKOhOcDs52FSIB4ZnYDtUcg/6E32Jdr5niPg0evI63VoDopC2fQfnLJ2dEZTvcHysMSp0uEyV86FIxYRHOVcSNaLfn+fbbZfOInH27I8TvlWi3BX2n+tSgVsTmqUcyiuxXWKk2ITSFQ6Iivw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768185957; c=relaxed/simple; bh=t3fqYup1Q4i1hX+rY6sipxB1IioFo7OZLWHTUppIxwE=; h=From:Message-ID:Date:MIME-Version:Subject:To:Cc:References: In-Reply-To:Content-Type; b=Uocwz+RMC9dll90tx6tYIeeMjbA0hfBW7141UYHHg4xis118qaa3cPxTqYPYcgCUiB11l3v3aMwtYvMCtmenXFagcEZ9ventmiG0vu+oHKMDdwEgXq4Qyfk3YotfjXGSpWjCWOGgrd97BW9viFCbLAYvghs0WVDTr0Ha4PS7tLg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=RIHtvEL6; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=OQaguD4O; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RIHtvEL6"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="OQaguD4O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768185954; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xcS5shRmDCmvz+IoTKqWTzUo+o6AAuc9PAErT+qJLAs=; b=RIHtvEL6WNI17SXaRSRMorIVqYMrxh0ySwzskBkEaln1u8krV+tG1S/A7Lr5TCnZ/xmPyZ KtKNrpQmrQ45jIQpgu6HJ7A1kYnPaFHjPmwVj/b5VXojhbjSh2ImKwg3YSG+yXekkmAAns oUF53XL9SgyNuCR2Z2VN4mMm5KjFmL8= Received: from mail-vk1-f197.google.com (mail-vk1-f197.google.com [209.85.221.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-570-7yyz4HtvOIGAqGYP54Cxtw-1; Sun, 11 Jan 2026 21:45:53 -0500 X-MC-Unique: 7yyz4HtvOIGAqGYP54Cxtw-1 X-Mimecast-MFC-AGG-ID: 7yyz4HtvOIGAqGYP54Cxtw_1768185953 Received: by mail-vk1-f197.google.com with SMTP id 71dfb90a1353d-5634c07c868so1903669e0c.3 for ; Sun, 11 Jan 2026 18:45:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1768185953; x=1768790753; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:content-language:references :cc:to:subject:user-agent:mime-version:date:message-id:from:from:to :cc:subject:date:message-id:reply-to; bh=xcS5shRmDCmvz+IoTKqWTzUo+o6AAuc9PAErT+qJLAs=; b=OQaguD4OW/a0PRcKXewnQoJz2HveUAELXWyoGoFSB4eakOiaN7tvkhvroIJENmrFeJ PuXhQwOuoS0ZPVBot7jNgIujYR/bmcdJMtq1VBx7U0wi1aj+iIuW4r/6YuomR+XN0y9v sSRuVS20/+rxYnHwdp+oQyGga1ktao5cj7wHS/C0jbSqfrBDZZVwi5JksbrL92hPebwY fLaRsznU4Ph/uhnaDGP5GyNfrYYkj71sNtZ7TZOgK0l/7FzeYA6/q8LhcJGUMV4nZinF gcNf58MM8flPh5y8Kkcdqu/uhs8VpBTqx5/327LJT+G9ApAPx2w6zzFUoq4SKNY3v0qk QpfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768185953; x=1768790753; h=content-transfer-encoding:in-reply-to:content-language:references :cc:to:subject:user-agent:mime-version:date:message-id:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=xcS5shRmDCmvz+IoTKqWTzUo+o6AAuc9PAErT+qJLAs=; b=IBYofk7JIrh9SmvihJAqEcj2spBdiiUVEj/5HowZHlp2RF+romp90l/jKg6Nssod2T WqQcDfPDcAMzLnGbnufjU38Fyr71xytygPgBDBX+5hn/+WMpEgv7X5ykgvoKu+wWjl4O SOq/DjA/FdWuQ8X1Ecy56OqotMi/ZRd9PGk6Cy8ppElObC0LJA3Wg7bOZap/1hc5vJ5j i1XURT3Nby5LxYlqBqBxfGZYOExQQtJeu5mm1MFVJzpzuzSxTHY1tQ8XRDSrUAhS7Xvz VVceUrXJNGOMbwv9bJI8mmxgqwYnU/P7fioZkLiAypGQr9ctgMqfB9HukAn7ZKy/q8Kh 7lww== X-Forwarded-Encrypted: i=1; AJvYcCWfakZRsw5+bUcyxDtlV4bGC5oxOo44Iplkjvi0DowdxE9WtnGtEqepZghosawwm0Qlpjos02eo@vger.kernel.org X-Gm-Message-State: AOJu0Yyzau8CGjTAYydag/h1u9M2klniIJ2ApqkedzI4sJwLU2c+xRwe 7pTVmNdM2PCT/dsxIbZL/3A+Puke/2wF9kNWPSMy6QZVeS7hW0xrk2oTcjLm9dZr7iwAc8yW8h8 Tf3R21OXKTQwOyDQiAZlPS4syS8katsNvwin56Qu0X3EB/2Kpena947mTqMI= X-Gm-Gg: AY/fxX4MqLON1bBxhNScH/5g1rOSqfflgLFuVMyhU9bnYK4+Mbnimi1vw9drnaPNOW2 o1U/cuGA9DJFTDa5Tdyx7YQp4YefmN6r9f2pV7Q2DOmZI/C17q51T7Q/VyMN4jNWPNeNxu/mnaE tyDwPQWFhSsfpuHVEOcKXBWdifhqNeQsNtsC1LFTewX1oIF4H2iNXWUfKFGW9pzCkLLsBd275m6 rHXOOLCM+xZ/loa2srdl0E30KRwfkkaXX2gGxTXaKz9V6HfBWcj/qWHdZEZUXnzd4lgRAkue1B4 vA0zkZBzkINaoiWW6o5e5EiG5aXbTFfsf17BPXBpCKB8HlmvMoN9zlXDGbYJ2AB1/SuhMM418j0 q90ARzuyZxUg/bUaPvQPRHcD+6veGn+8i3roUCYGsOSyqCpkMbCQATAbz X-Received: by 2002:a05:6122:1d4d:b0:55b:1a1b:3273 with SMTP id 71dfb90a1353d-56347d4a0bemr5054201e0c.6.1768185952710; Sun, 11 Jan 2026 18:45:52 -0800 (PST) X-Google-Smtp-Source: AGHT+IEwOFp6cPvfkUcSbRWdkrghqM2mUWR9n3I0P3Nk8PJy6T841SLsur+1hpT47PiYyZ5sXMn8AA== X-Received: by 2002:a05:6122:1d4d:b0:55b:1a1b:3273 with SMTP id 71dfb90a1353d-56347d4a0bemr5054194e0c.6.1768185952291; Sun, 11 Jan 2026 18:45:52 -0800 (PST) Received: from ?IPV6:2601:188:c102:b180:1f8b:71d0:77b1:1f6e? ([2601:188:c102:b180:1f8b:71d0:77b1:1f6e]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-563667cf148sm8166160e0c.2.2026.01.11.18.45.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 11 Jan 2026 18:45:51 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <18ee9089-8a08-44ed-8761-7c9db765cd4e@redhat.com> Date: Sun, 11 Jan 2026 21:45:36 -0500 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 13/33] sched/isolation: Convert housekeeping cpumasks to rcu pointers To: Simon Horman , Frederic Weisbecker Cc: LKML , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org References: <20260101221359.22298-1-frederic@kernel.org> <20260101221359.22298-14-frederic@kernel.org> <20260107115653.GA196631@kernel.org> Content-Language: en-US In-Reply-To: <20260107115653.GA196631@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 1/7/26 6:56 AM, Simon Horman wrote: > On Thu, Jan 01, 2026 at 11:13:38PM +0100, Frederic Weisbecker wrote: >> HK_TYPE_DOMAIN's cpumask will soon be made modifiable by cpuset. >> A synchronization mechanism is then needed to synchronize the updates >> with the housekeeping cpumask readers. >> >> Turn the housekeeping cpumasks into RCU pointers. Once a housekeeping >> cpumask will be modified, the update side will wait for an RCU grace >> period and propagate the change to interested subsystem when deemed >> necessary. >> >> Signed-off-by: Frederic Weisbecker >> --- >> kernel/sched/isolation.c | 58 +++++++++++++++++++++++++--------------- >> kernel/sched/sched.h | 1 + >> 2 files changed, 37 insertions(+), 22 deletions(-) >> >> diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c >> index 11a623fa6320..83be49ec2b06 100644 >> --- a/kernel/sched/isolation.c >> +++ b/kernel/sched/isolation.c >> @@ -21,7 +21,7 @@ DEFINE_STATIC_KEY_FALSE(housekeeping_overridden); >> EXPORT_SYMBOL_GPL(housekeeping_overridden); >> >> struct housekeeping { >> - cpumask_var_t cpumasks[HK_TYPE_MAX]; >> + struct cpumask __rcu *cpumasks[HK_TYPE_MAX]; >> unsigned long flags; >> }; >> >> @@ -33,17 +33,28 @@ bool housekeeping_enabled(enum hk_type type) >> } >> EXPORT_SYMBOL_GPL(housekeeping_enabled); >> >> +const struct cpumask *housekeeping_cpumask(enum hk_type type) >> +{ >> + if (static_branch_unlikely(&housekeeping_overridden)) { >> + if (housekeeping.flags & BIT(type)) { >> + return rcu_dereference_check(housekeeping.cpumasks[type], 1); >> + } >> + } >> + return cpu_possible_mask; >> +} >> +EXPORT_SYMBOL_GPL(housekeeping_cpumask); >> + > Hi Frederic, > > I think this patch should also update the access to housekeeping.cpumasks > in housekeeping_setup(), on line 200, to use housekeeping_cpumask(). > > As is, sparse flags __rcu a annotation miss match there. > > kernel/sched/isolation.c:200:80: warning: incorrect type in argument 3 (different address spaces) > kernel/sched/isolation.c:200:80: expected struct cpumask const *srcp3 > kernel/sched/isolation.c:200:80: got struct cpumask [noderef] __rcu * > > ... > The direct housekeeping.cpumasks[type] reference is in the newly merged check after Federic's initial patch series.                 iter_flags = housekeeping.flags & (HK_FLAG_KERNEL_NOISE | HK_FLAG_DOMAIN);                 type = find_first_bit(&iter_flags, HK_TYPE_MAX);                 /*                  * Pass the check if none of these flags were previously set or                  * are not in the current selection.                  */                 iter_flags = flags & (HK_FLAG_KERNEL_NOISE | HK_FLAG_DOMAIN);                 first_cpu = (type == HK_TYPE_MAX || !iter_flags) ? 0 : cpumask_first_and_and(cpu_present_mask,                                     housekeeping_staging, housekeeping.cpumasks[type]); Maybe that is why it is missed. Cheers, Longman