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From: Thomas Gleixner <tglx@linutronix.de>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>,
	"Shivappa, Vikas" <vikas.shivappa@intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
	"Yu, Fenghua" <fenghua.yu@intel.com>,
	"ak@linux.intel.com" <ak@linux.intel.com>,
	"eranian@google.com" <eranian@google.com>,
	"davidcc@google.com" <davidcc@google.com>
Subject: RE: [PATCH 1/2] x86/intel_rdt/mbm: Fix MBM overflow handler during hot cpu
Date: Wed, 16 Aug 2017 16:57:41 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1708161656320.1987@nanos> (raw)
In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F61340139@ORSMSX114.amr.corp.intel.com>

On Wed, 16 Aug 2017, Luck, Tony wrote:
> > You could alternatively use flush and make the worker code schedule the
> > work on a still online CPU in the domain instead of blindly rescheduling it
> > on the same CPU.
> 
> We looked at that when you suggested flush. The problem is that we have
> already deleted the current cpu from the bitmask for the domain. So the
> worker code doesn't know which domain it is running on, so can't pick
> another.
> 
> If we try to do the flush before dropping the cpu from the bitmask, then
> the worker code doesn't have any reason to pick a different CPU.
> 
> Is there is some cheap "I'm running on a CPU that is in the process of going
> offline" test that we could make in the worker code?

Don't think so. It was just a thought, but the code as provided is fine and
merged as is.

Thanks,

	tglx

  reply	other threads:[~2017-08-16 14:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-16  1:00 [PATCH 0/2 V4] Cqm3 support based on resctrl along with MBM Vikas Shivappa
2017-08-16  1:00 ` [PATCH 1/2] x86/intel_rdt/mbm: Fix MBM overflow handler during hot cpu Vikas Shivappa
2017-08-16  9:19   ` Thomas Gleixner
2017-08-16 14:53     ` Luck, Tony
2017-08-16 14:57       ` Thomas Gleixner [this message]
2017-08-16 10:13   ` [tip:x86/cache] x86/intel_rdt/mbm: Fix MBM overflow handler during CPU hotplug tip-bot for Vikas Shivappa
2017-08-16  1:00 ` [PATCH 2/2] x86/intel_rdt/cqm: Improve limbo list processing Vikas Shivappa
2017-08-16 10:13   ` [tip:x86/cache] " tip-bot for Vikas Shivappa

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