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From: John Hubbard <jhubbard@nvidia.com>
To: Yan Zhao <yan.y.zhao@intel.com>
Cc: David Hildenbrand <david@redhat.com>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>,
	<pbonzini@redhat.com>, <seanjc@google.com>,
	<mike.kravetz@oracle.com>, <apopple@nvidia.com>, <jgg@nvidia.com>,
	<rppt@kernel.org>, <akpm@linux-foundation.org>,
	<kevin.tian@intel.com>, Mel Gorman <mgorman@techsingularity.net>
Subject: Re: [RFC PATCH v2 0/5] Reduce NUMA balance caused TLB-shootdowns in a VM
Date: Mon, 14 Aug 2023 19:34:09 -0700	[thread overview]
Message-ID: <4271b91c-90b7-4b48-b761-b4535b2ae9b7@nvidia.com> (raw)
In-Reply-To: <ZNnvPuRUVsUl5umM@yzhao56-desk.sh.intel.com>

On 8/14/23 02:09, Yan Zhao wrote:
...
>> hmm_range_fault()-based memory management in particular might benefit
>> from having NUMA balancing disabled entirely for the memremap_pages()
>> region, come to think of it. That seems relatively easy and clean at
>> first glance anyway.
>>
>> For other regions (allocated by the device driver), a per-VMA flag
>> seems about right: VM_NO_NUMA_BALANCING ?
>>
> Thanks a lot for those good suggestions!
> For VMs, when could a per-VMA flag be set?
> Might be hard in mmap() in QEMU because a VMA may not be used for DMA until
> after it's mapped into VFIO.
> Then, should VFIO set this flag on after it maps a range?
> Could this flag be unset after device hot-unplug?
> 

I'm hoping someone who thinks about VMs and VFIO often can chime in.


thanks,
-- 
John Hubbard
NVIDIA



  reply	other threads:[~2023-08-15  2:34 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-10  8:56 Yan Zhao
2023-08-10  8:57 ` [RFC PATCH v2 1/5] mm/mmu_notifier: introduce a new mmu notifier flag MMU_NOTIFIER_RANGE_NUMA Yan Zhao
2023-08-10  8:58 ` [RFC PATCH v2 2/5] mm: don't set PROT_NONE to maybe-dma-pinned pages for NUMA-migrate purpose Yan Zhao
2023-08-10  9:00 ` [RFC PATCH v2 3/5] mm/mmu_notifier: introduce a new callback .numa_protect Yan Zhao
2023-08-10  9:00 ` [RFC PATCH v2 4/5] mm/autonuma: call .numa_protect() when page is protected for NUMA migrate Yan Zhao
2023-08-11 18:52   ` Nadav Amit
2023-08-14  7:52     ` Yan Zhao
2023-08-10  9:02 ` [RFC PATCH v2 5/5] KVM: Unmap pages only when it's indeed protected for NUMA migration Yan Zhao
2023-08-10 13:16   ` bibo mao
2023-08-11  3:45     ` Yan Zhao
2023-08-11  7:40       ` bibo mao
2023-08-11  8:01         ` Yan Zhao
2023-08-11 17:14           ` Sean Christopherson
2023-08-11 17:18             ` Jason Gunthorpe
2023-08-14  6:52             ` Yan Zhao
2023-08-14  7:44               ` Yan Zhao
2023-08-14 16:40               ` Sean Christopherson
2023-08-15  1:54                 ` Yan Zhao
2023-08-15 14:50                   ` Sean Christopherson
2023-08-16  2:43                     ` bibo mao
2023-08-16  3:44                       ` bibo mao
2023-08-16  5:14                         ` Yan Zhao
2023-08-16  7:29                           ` bibo mao
2023-08-16  7:18                             ` Yan Zhao
2023-08-16  7:53                               ` bibo mao
2023-08-16 13:39                                 ` Sean Christopherson
2023-08-10  9:34 ` [RFC PATCH v2 0/5] Reduce NUMA balance caused TLB-shootdowns in a VM David Hildenbrand
2023-08-10  9:50   ` Yan Zhao
2023-08-11 17:25     ` David Hildenbrand
2023-08-11 18:20       ` John Hubbard
2023-08-11 18:39         ` David Hildenbrand
2023-08-11 19:35           ` John Hubbard
2023-08-14  9:09             ` Yan Zhao
2023-08-15  2:34               ` John Hubbard [this message]
2023-08-16  7:43                 ` David Hildenbrand
2023-08-16  9:06                   ` Yan Zhao
2023-08-16  9:49                     ` David Hildenbrand
2023-08-16 18:00                       ` John Hubbard
2023-08-17  5:05                         ` Yan Zhao
2023-08-17  7:38                           ` David Hildenbrand
2023-08-18  0:13                             ` Yan Zhao
2023-08-18  2:29                               ` John Hubbard
2023-09-04  9:18                                 ` Yan Zhao
2023-08-15  2:36               ` Yuan Yao
2023-08-15  2:37                 ` Yan Zhao
2023-08-10 13:58 ` Chao Gao
2023-08-11  5:22   ` Yan Zhao

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