From nobody Sun Feb 8 12:18:52 2026 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 139023563D4 for ; Wed, 29 Oct 2025 16:21:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761754909; cv=none; b=mHKBrKNRF/YURftJITqHSaSQ/8Hx4k5G7ndF7MbKsNv5wh4BLGmy4deNd8OAXbUMt51U+YDqRc/MEsmYXPQsZ7Fu0/ZN3m1jo/Foz+x5LSxEIcDk9jzzoz6+mwXPf09GuqTraIV1Sv6w1qg5zBw6kSpGRgsc/qpVfIpLHDzJGTU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761754909; c=relaxed/simple; bh=Zb98oa5Tsu6FZrHnx3+dZazYWKu06/vufasATYdm/DA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZN5hIIKrP7cDpV9wFXZpRVf04oqvBHKcVl5Xwy78yQdrSksyYwcGTf5aedVUCCM7ZuvUBuWUdGg02ACwIkQmE+FmXjFfOkB6Q/OsUuZF9cZtVFlxqQZPcb5O6skzxUYUPalF6KIepm0JO9pOKZ1qjRD+QuJmyC9pXvy2ZmnTI98= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=oHN+5PUh; arc=none smtp.client-ip=198.175.65.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="oHN+5PUh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1761754907; x=1793290907; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Zb98oa5Tsu6FZrHnx3+dZazYWKu06/vufasATYdm/DA=; b=oHN+5PUhR5JtzCpd/rb+u0BLII+HqSazgwLthhPKX4PqDo19pW4Cw3NI qFEmdJufFS2S6lJV4ghjizpt7TCdt/cayD1bYGOcAG1IgnqPwtbrXGl4O SbT/ulv3qhV465NH3jI8KF0b6gyfjyJgYWRf3oAJoLn/biE0T0/rfN4Ef p0TKlG8zXpUt0pQh7e+5jbf5Jni/Zxk09d87Km8+Kyp+TJUxCN+meHL0J fnoS1Lk86bKC9sZXkJSc2iq4A+j4Pf3nfX17y1nr/7a89I64dGzJZRMA6 rWtxLswwwqVtJ8QVnb1jfShte3OwjOO3MeHPibq4b/GllsYw7sxjzYqnP g==; X-CSE-ConnectionGUID: c+GgT1KFTLy/Jp7WuBQp0Q== X-CSE-MsgGUID: BwrZlYuBRF6LeY/gUnitUQ== X-IronPort-AV: E=McAfee;i="6800,10657,11597"; a="75331043" X-IronPort-AV: E=Sophos;i="6.19,264,1754982000"; d="scan'208";a="75331043" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Oct 2025 09:21:35 -0700 X-CSE-ConnectionGUID: IknzJvYIQUqtfIC8WtyrUQ== X-CSE-MsgGUID: CnwwZxWUQ6OeNYsow0KIlw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,264,1754982000"; d="scan'208";a="184901404" Received: from mgerlach-mobl1.amr.corp.intel.com (HELO agluck-desk3.home.arpa) ([10.124.223.146]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Oct 2025 09:21:35 -0700 From: Tony Luck To: Fenghua Yu , Reinette Chatre , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , Drew Fustini , Dave Martin , Chen Yu Cc: x86@kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Tony Luck Subject: [PATCH v13 27/32] x86,fs/resctrl: Compute number of RMIDs as minimum across resources Date: Wed, 29 Oct 2025 09:21:10 -0700 Message-ID: <20251029162118.40604-28-tony.luck@intel.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251029162118.40604-1-tony.luck@intel.com> References: <20251029162118.40604-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" resctrl assumes that only the L3 resource supports monitor events, so it simply takes the rdt_resource::num_rmid from RDT_RESOURCE_L3 as the system's number of RMIDs. The addition of telemetry events in a different resource breaks that assumption. Compute the number of available RMIDs as the minimum value across all mon_capable resources (analogous to how the number of CLOSIDs is computed across alloc_capable resources). Note that mount time enumeration of the telemetry resource means that this number can be reduced. If this happens, then some memory will be wasted as the allocations for rdt_l3_mon_domain::mbm_states[] and rdt_l3_mon_domain::rmid_busy_llc created during resctrl initialization will be larger than needed. Signed-off-by: Tony Luck Reviewed-by: Reinette Chatre --- arch/x86/kernel/cpu/resctrl/core.c | 15 +++++++++++++-- fs/resctrl/rdtgroup.c | 6 ++++++ 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resct= rl/core.c index a8eb197e27db..9eb1bca9436b 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -110,12 +110,23 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESO= URCES] =3D { }, }; =20 +/** + * resctrl_arch_system_num_rmid_idx - Compute number of supported RMIDs + * (minimum across all mon_capable resource) + * + * Return: Number of supported RMIDs at time of call. Note that mount time + * enumeration of resources may reduce the number. + */ u32 resctrl_arch_system_num_rmid_idx(void) { - struct rdt_resource *r =3D &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl; + u32 num_rmids =3D U32_MAX; + struct rdt_resource *r; + + for_each_mon_capable_rdt_resource(r) + num_rmids =3D min(num_rmids, r->mon.num_rmid); =20 /* RMID are independent numbers for x86. num_rmid_idx =3D=3D num_rmid */ - return r->mon.num_rmid; + return num_rmids =3D=3D U32_MAX ? 0 : num_rmids; } =20 struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l) diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index b67faf6a5012..15b2765898d6 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -4286,6 +4286,12 @@ void resctrl_offline_mon_domain(struct rdt_resource = *r, struct rdt_domain_hdr *h * During boot this may be called before global allocations have been made= by * resctrl_l3_mon_resource_init(). * + * Called during CPU online that may run as soon as CPU online callbacks + * are set up during resctrl initialization. The number of supported RMIDs + * may be reduced if additional mon_capable resources are enumerated + * at mount time. This means the rdt_l3_mon_domain::mbm_states[] and + * rdt_l3_mon_domain::rmid_busy_llc allocations may be larger than needed. + * * Return: 0 for success, or -ENOMEM. */ static int domain_setup_l3_mon_state(struct rdt_resource *r, struct rdt_l3= _mon_domain *d) --=20 2.51.0