From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A28704EC646 for ; Mon, 7 Sep 2026 14:02:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788789731; cv=none; b=kLyCBDwW97YuMI+6DeV+guXmpMqDAIT/1xaJNC6Wk3nM/PuXQipYQ8WTHuy2drVwAt37i3q7GiIuoz/hMZPWEdPfqPBynU5URdsWrAha0n0w4sdo+B2yhXVTmE+aJjt8YdE7cYrIGi6k0tjV/8hK4HeWYg6YysLHknEICkdq+K4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788789731; c=relaxed/simple; bh=oA/AdAjxhNjtwc1Lrk6qquh95AYfGVwGHutvBnoLC6U=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oj8mr+U+m+8B9yXT7A/TPGiAKOoZPWfy9Q2oNsHzJuWJwvrWbz453URgADKeHMdduusHR0JOrsV1t3q3FRW6vBqppuw4/HvD4UKzGlLpe+nBUuN4jiaAVUThDwjBf4G62f5OXDD4GIQdLg0bjMdSVvk+Qvhwv9De0ObLR3dOCjM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=Ns5v0J2Y; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="Ns5v0J2Y" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 06DCB1476; Mon, 7 Sep 2026 07:02:05 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C3DD53F528; Mon, 7 Sep 2026 07:02:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788789728; bh=oA/AdAjxhNjtwc1Lrk6qquh95AYfGVwGHutvBnoLC6U=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Ns5v0J2YvGYVoHRTTsZV9OtLrblHHZXXcaeylCj9DLtSNjaRqhaCUdWovQP79SbRT ftFJxhipFotB29XIARYbwnVQf1IwOy/WTZ+cjn64T66fYIYvWATsoPofR+PtYHKDib jav3MKmIaL6WIymr/t7JA6LQpqnptjVU+PSUj0JU= Message-ID: <3e93f413-2d51-4647-bda4-f1aad6ad1820@arm.com> Date: Mon, 7 Sep 2026 15:02:06 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm_mpam: Only schedule mpam_enable work after first successful MSC probe To: "ping.li" , james.morse@arm.com Cc: linux-kernel@vger.kernel.org, reinette.chatre@intel.com, fenghuay@nvidia.com, "ping.li" References: <20260818130646.663778-1-ping.li@horizon.auto_quarantine> Content-Language: en-US From: Ben Horgan In-Reply-To: <20260818130646.663778-1-ping.li@horizon.auto_quarantine> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Ping, Thanks for the patch and sorry for the delay in replying; I had to dig this e-mail out of quarantine. On 18/08/2026 14:06, ping.li wrote: > mpam_discovery_cpu_online() sets new_device_probed unconditionally after > processing each reachable MSC. Once an MSC has already been probed > (msc->probed is true), later CPUs sharing it skip > mpam_msc_hw_probe() but still leave err at its default value of 0. > As a result, new_device_probed is still set to true, causing > mpam_enable_work to be scheduled again even though no new hardware was > probed. > > Set new_device_probed only when mpam_msc_hw_probe() is called and > succeeds. > > Fixes: 8f8d0ac1da78 ("arm_mpam: Add cpuhp callbacks to probe MSC hardware") Are the extra mpam_enable() calls causing any harm or can this be considered just an optimzsation? If they aren't causing any real issues then there is no need for the fixes tag. > Signed-off-by: ping.li > --- > drivers/resctrl/mpam_devices.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index 2f09f4b78bd3..fefdcf588932 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c > @@ -1866,13 +1866,15 @@ static int mpam_discovery_cpu_online(unsigned int cpu) > continue; > > mutex_lock(&msc->probe_lock); > - if (!msc->probed) > + if (!msc->probed) { > err = mpam_msc_hw_probe(msc); > + if (!err) > + new_device_probed = true; > + }> mutex_unlock(&msc->probe_lock); > > if (err) > break; > - new_device_probed = true; > } > > if (new_device_probed && !err) The code change looks good to me. Thanks, Ben