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From: Thomas Gleixner <tglx@linutronix.de>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>,
	fenghua.yu@intel.com, tony.luck@intel.com,
	gavin.hindman@intel.com, vikas.shivappa@linux.intel.com,
	dave.hansen@intel.com, mingo@redhat.com, hpa@zytor.com,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH V2 13/22] x86/intel_rdt: Support schemata write - pseudo-locking core
Date: Wed, 21 Feb 2018 09:34:57 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.21.1802210934060.24268@nanos.tec.linutronix.de> (raw)
In-Reply-To: <2db87a79-e13f-ad6b-c399-1ad58585f38e@oracle.com>

On Tue, 20 Feb 2018, Mike Kravetz wrote:
> On 02/20/2018 03:21 PM, Thomas Gleixner wrote:
> > The other problem is that we'd need to have MAP_CONTIG first so you
> > actually can allocate physically contigous memory from user space. Mike is
> > working on that, but it's not available today. The only way to do so today
> > (with lots of waste) would be MAP_HUGETLB, which might be an acceptable
> > constraint up to the point where MAP_CONTIG is available.
> 
> Just to clarify, there is not any activity on exposing a general purpose
> MAP_CONTIG interface to user space.  When initially proposed, MAP_CONTIG
> was shot down and the suggestion was to create a new in kernel interface
> to make allocation of contiguous pages easier.  The initial use case was
> a driver which could use the new internal interface as part of it's
> mmap() routine to give contiguous regions to user space.

Thanks for the clarification.

> Reinette is using this new interface, but that must be for the ?immediate
> allocation? case you are trying to move away from.  Sorry, I have not been
> following development of this feature.
> 
> If you would have to create a device to accept a user buffer, could you
> perhaps use the same device to create/hand out a contiguous mapping?

Yes, that's straight forward.

Thanks,

	tglx

  parent reply	other threads:[~2018-02-21  8:35 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-13 15:46 [RFC PATCH V2 00/22] Intel(R) Resource Director Technology Cache Pseudo-Locking enabling Reinette Chatre
2018-02-13 15:46 ` Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 01/22] x86/intel_rdt: Documentation for Cache Pseudo-Locking Reinette Chatre
2018-02-19 20:35   ` Thomas Gleixner
2018-02-19 22:15     ` Reinette Chatre
2018-02-19 22:19       ` Thomas Gleixner
2018-02-19 22:24         ` Reinette Chatre
2018-02-19 21:27   ` Randy Dunlap
2018-02-19 22:21     ` Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 02/22] x86/intel_rdt: Make useful functions available internally Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 03/22] x86/intel_rdt: Introduce hooks to create pseudo-locking files Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 04/22] x86/intel_rdt: Introduce test to determine if closid is in use Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 05/22] x86/intel_rdt: Print more accurate pseudo-locking availability Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 06/22] x86/intel_rdt: Create pseudo-locked regions Reinette Chatre
2018-02-19 20:57   ` Thomas Gleixner
2018-02-19 23:02     ` Reinette Chatre
2018-02-19 23:16       ` Thomas Gleixner
2018-02-20  3:21         ` Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 07/22] x86/intel_rdt: Connect pseudo-locking directory to operations Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 08/22] x86/intel_rdt: Introduce pseudo-locking resctrl files Reinette Chatre
2018-02-19 21:01   ` Thomas Gleixner
2018-02-13 15:46 ` [RFC PATCH V2 09/22] x86/intel_rdt: Discover supported platforms via prefetch disable bits Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 10/22] x86/intel_rdt: Disable pseudo-locking if CDP enabled Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 11/22] x86/intel_rdt: Associate pseudo-locked regions with its domain Reinette Chatre
2018-02-19 21:19   ` Thomas Gleixner
2018-02-19 23:00     ` Reinette Chatre
2018-02-19 23:19       ` Thomas Gleixner
2018-02-20  3:17         ` Reinette Chatre
2018-02-20 10:00           ` Thomas Gleixner
2018-02-20 16:02             ` Reinette Chatre
2018-02-20 17:18               ` Thomas Gleixner
2018-02-13 15:46 ` [RFC PATCH V2 12/22] x86/intel_rdt: Support CBM checking from value and character buffer Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 13/22] x86/intel_rdt: Support schemata write - pseudo-locking core Reinette Chatre
2018-02-20 17:15   ` Thomas Gleixner
2018-02-20 18:47     ` Reinette Chatre
2018-02-20 23:21       ` Thomas Gleixner
2018-02-21  1:58         ` Mike Kravetz
2018-02-21  6:10           ` Reinette Chatre
2018-02-21  8:34           ` Thomas Gleixner [this message]
2018-02-21  5:58         ` Reinette Chatre
2018-02-27  0:34     ` Reinette Chatre
2018-02-27 10:36       ` Thomas Gleixner
2018-02-27 15:38         ` Thomas Gleixner
2018-02-27 19:52         ` Reinette Chatre
2018-02-27 21:33           ` Reinette Chatre
2018-02-28 18:39           ` Thomas Gleixner
2018-02-28 19:17             ` Reinette Chatre
2018-02-28 19:40               ` Thomas Gleixner
2018-02-27 21:01     ` Reinette Chatre
2018-02-28 17:57       ` Thomas Gleixner
2018-02-28 17:59         ` Thomas Gleixner
2018-02-28 18:34           ` Reinette Chatre
2018-02-28 18:42             ` Thomas Gleixner
2018-02-13 15:46 ` [RFC PATCH V2 14/22] x86/intel_rdt: Enable testing for pseudo-locked region Reinette Chatre
2018-02-13 15:46 ` [RFC PATCH V2 15/22] x86/intel_rdt: Prevent new allocations from pseudo-locked regions Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 16/22] x86/intel_rdt: Create debugfs files for pseudo-locking testing Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 17/22] x86/intel_rdt: Create character device exposing pseudo-locked region Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 18/22] x86/intel_rdt: More precise L2 hit/miss measurements Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 19/22] x86/intel_rdt: Support L3 cache performance event of Broadwell Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 20/22] x86/intel_rdt: Limit C-states dynamically when pseudo-locking active Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 21/22] mm/hugetlb: Enable large allocations through gigantic page API Reinette Chatre
2018-02-13 15:47   ` Reinette Chatre
2018-02-13 15:47 ` [RFC PATCH V2 22/22] x86/intel_rdt: Support contiguous memory of all sizes Reinette Chatre
2018-02-14 18:12 ` [RFC PATCH V2 00/22] Intel(R) Resource Director Technology Cache Pseudo-Locking enabling Mike Kravetz
2018-02-14 18:12   ` Mike Kravetz
2018-02-14 18:31   ` Reinette Chatre
2018-02-14 18:31     ` Reinette Chatre
2018-02-15 20:39     ` Reinette Chatre
2018-02-15 20:39       ` Reinette Chatre
2018-02-15 21:10       ` Mike Kravetz
2018-02-15 21:10         ` Mike Kravetz

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