From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="q28rMezC" Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A50E6BD for ; Fri, 8 Dec 2023 10:26:17 -0800 (PST) Received: by mail-pl1-x62e.google.com with SMTP id d9443c01a7336-1d0b40bb704so10525ad.0 for ; Fri, 08 Dec 2023 10:26:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1702059977; x=1702664777; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=75zio9oghTkUElUZUVPQLES5Kw5emjlawW+mI0eiLfs=; b=q28rMezCcPtRMa56QW+O2YFjtrVIezvWd0PlN5IELBdx6Qoc6lBjG+tG8yxKCXTNKm qR20DY8hoUu+cIAiUatPbRhg6AuazGWNCvNpp9iGQI/ualX2Vh0X1L/nN9h/FGxBj8iP HnS3xS8bdLcTpYuAR0rdGJNLYwVddVtjLnlU48xp0sGJm/pMxUnDgbtT9iKEbH4HRR2b GTy3VmMOPKogjYiBEU65GRXtvUoagI7o9QucyUQH2oWBWKL3tCDDYBeseHgpEqMkLlzR vl5fuAX/KiWEqzNk1xf67ygRQWkPtsmoUGtcBhLIkcQK79Xz5EuygGHhZUnrOKLvgyH6 8xZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702059977; x=1702664777; h=content-transfer-encoding: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=75zio9oghTkUElUZUVPQLES5Kw5emjlawW+mI0eiLfs=; b=UD/vqVtE2t9NlAtS/SdVQecR3N311ho0Ke/feK+jUJ30FKUzQZomj0bY1e4DnpvTOf tfi15T3sRVcB6O1BBUEZfkrKsrR1uaEzL84wmBZ6XAHki+2/ITie1uWjWTAKaMVS7Oge pmsZKDmGTmptKiJ6qRTydKNCLBb9USYoZfB8bQWc7YjGYZFvjJSnMthmj92TCKuX8Cc4 Q1ccftVuOwu376/I0vjP9Qzd3IHBS+EkZ6eyXtcfBC5h5p4IeNYh4oets6rlYwWT3fKG 3bfwc9yMNQeBLUKW9jy/DrIDQCz9Z5UXMtNaaq03I9VDpOU1moiHPxWOt6O9wogGYDZ5 uVDw== X-Gm-Message-State: AOJu0YwxqNkz+gjtv6zuK5VpwJhh8+ozMasH4+70QyDPkQj5G6LFXcp1 XWgh1h1DFMif4tYOLtBKUI7WZaENRn1EP6cwgx/uqA== X-Google-Smtp-Source: AGHT+IG1AfEt/Tw51pB1tsGJgVQsx5i9xByxbif3lqRSlA8jKdPIkrRKdier/oxRIv+d1qmJOHXgkvTs0WvAfHdNXkE= X-Received: by 2002:a17:903:244f:b0:1cf:9f0e:9524 with SMTP id l15-20020a170903244f00b001cf9f0e9524mr175431pls.27.1702059976843; Fri, 08 Dec 2023 10:26:16 -0800 (PST) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20231201214737.104444-1-tony.luck@intel.com> <20231207195613.153980-1-tony.luck@intel.com> <20231207195613.153980-3-tony.luck@intel.com> In-Reply-To: <20231207195613.153980-3-tony.luck@intel.com> From: Peter Newman Date: Fri, 8 Dec 2023 10:26:06 -0800 Message-ID: Subject: Re: [PATCH v6 2/3] x86/resctrl: Use total bandwidth for mba_MBps option when local isn't present To: Tony Luck Cc: Fenghua Yu , Reinette Chatre , Jonathan Corbet , Shuah Khan , x86@kernel.org, Shaopeng Tan , James Morse , Jamie Iles , Babu Moger , Randy Dunlap , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, patches@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, Dec 7, 2023 at 11:56=E2=80=AFAM Tony Luck wro= te: > > On Intel systems the memory bandwidth monitoring events are > independently enumerated. It is possible for a system to support > total memory bandwidth monitoring, but not support local bandwidth > monitoring. On such a system a user could not enable mba_sc mode. > Users will see this highly unhelpful error message from mount: > > # mount -t resctrl -o mba_MBps resctrl /sys/fs/resctrl > mount: /sys/fs/resctrl: wrong fs type, bad option, bad superblock on > resctrl, missing codepage or helper program, or other error. > dmesg(1) may have more information after failed mount system call. > > dmesg(1) does not provide any additional information. > > Modify the existing "mba_MBps" mount option to switch to total bandwidth > monitoring if local monitoring is not available. > > Signed-off-by: Tony Luck > --- > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu= /resctrl/rdtgroup.c > index 5f64a0b2597c..7410513db45a 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -2725,6 +2725,8 @@ static int rdt_parse_param(struct fs_context *fc, s= truct fs_parameter *param) > return -EINVAL; > if (is_mbm_local_enabled()) > ctx->enable_mba_mbps_local =3D true; > + else if (is_mbm_total_enabled()) > + ctx->enable_mba_mbps_total =3D true; > else > return -EINVAL; > return 0; > -- > 2.41.0 > Reviewed-by: Peter Newman