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From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>,
	Christoph Hellwig <hch@infradead.org>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	J??r??me Glisse <jglisse@redhat.com>,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	Jan Kara <jack@suse.cz>, Pawel Osciak <pawel@osciak.com>,
	KVM list <kvm@vger.kernel.org>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Tomasz Figa <tfiga@chromium.org>, Linux MM <linux-mm@kvack.org>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Daniel Vetter <daniel.vetter@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	"open list:DMA BUFFER SHARING FRAMEWORK" 
	<linux-media@vger.kernel.org>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Subject: Re: [PATCH v5 05/15] mm/frame-vector: Use FOLL_LONGTERM
Date: Wed, 4 Nov 2020 19:11:00 +0000	[thread overview]
Message-ID: <20201104191100.GA25011@infradead.org> (raw)
In-Reply-To: <20201104190214.GW36674@ziepe.ca>

On Wed, Nov 04, 2020 at 03:02:14PM -0400, Jason Gunthorpe wrote:
> I saw that once and I really couldn't make sense of it..
> What use is having futex's that only work on THP pages? Confused
> 
> CH said there was no case of HAVE_FAST_GUP !ARCH_HAS_PTE_SPECIAL, is
> one hidden someplace then?

ARCH_HAS_PTE_SPECIAL is selected by:

arc
arm		(if LPAE)
arm64
mips		(if !(32BIT && CPU_HAS_RIXI))
powerpc
riscv
s390
sh
sparc		(if SPARC64)
x86

HAVE_FAST_GUP is supported by:

arm		(if LPAE)
arm64
mips
powerpc
s390
sh
x86

so mips would be a candidate.  But I think only in theory, as
the options selecting CPU_HAS_RIXI do not select
CPU_SUPPORTS_HUGEPAGES.  Adding the mips maintainer to double check
my logic.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	Jan Kara <jack@suse.cz>, KVM list <kvm@vger.kernel.org>,
	Pawel Osciak <pawel@osciak.com>,
	Daniel Vetter <daniel.vetter@intel.com>,
	John Hubbard <jhubbard@nvidia.com>,
	LKML <linux-kernel@vger.kernel.org>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Tomasz Figa <tfiga@chromium.org>,
	Christoph Hellwig <hch@infradead.org>,
	Linux MM <linux-mm@kvack.org>,
	J??r??me Glisse <jglisse@redhat.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	"open list:DMA BUFFER SHARING FRAMEWORK"
	<linux-media@vger.kernel.org>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH v5 05/15] mm/frame-vector: Use FOLL_LONGTERM
Date: Wed, 4 Nov 2020 19:11:00 +0000	[thread overview]
Message-ID: <20201104191100.GA25011@infradead.org> (raw)
In-Reply-To: <20201104190214.GW36674@ziepe.ca>

On Wed, Nov 04, 2020 at 03:02:14PM -0400, Jason Gunthorpe wrote:
> I saw that once and I really couldn't make sense of it..
> What use is having futex's that only work on THP pages? Confused
> 
> CH said there was no case of HAVE_FAST_GUP !ARCH_HAS_PTE_SPECIAL, is
> one hidden someplace then?

ARCH_HAS_PTE_SPECIAL is selected by:

arc
arm		(if LPAE)
arm64
mips		(if !(32BIT && CPU_HAS_RIXI))
powerpc
riscv
s390
sh
sparc		(if SPARC64)
x86

HAVE_FAST_GUP is supported by:

arm		(if LPAE)
arm64
mips
powerpc
s390
sh
x86

so mips would be a candidate.  But I think only in theory, as
the options selecting CPU_HAS_RIXI do not select
CPU_SUPPORTS_HUGEPAGES.  Adding the mips maintainer to double check
my logic.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-11-04 19:11 UTC|newest]

Thread overview: 212+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-30 10:08 [PATCH v5 00/15] follow_pfn and other iomap races Daniel Vetter
2020-10-30 10:08 ` Daniel Vetter
2020-10-30 10:08 ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 01/15] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 02/15] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 03/15] misc/habana: Stop using frame_vector helpers Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 04/15] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 05/15] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 14:11   ` Tomasz Figa
2020-10-30 14:11     ` Tomasz Figa
2020-10-30 14:11     ` Tomasz Figa
2020-10-30 14:37     ` Daniel Vetter
2020-10-30 14:37       ` Daniel Vetter
2020-10-30 14:37       ` Daniel Vetter
2020-11-02 18:19       ` Tomasz Figa
2020-11-02 18:19         ` Tomasz Figa
2020-11-02 18:19         ` Tomasz Figa
2020-10-31  2:55   ` John Hubbard
2020-10-31  2:55     ` John Hubbard
2020-10-31  2:55     ` John Hubbard
2020-10-31 14:45     ` Daniel Vetter
2020-10-31 14:45       ` Daniel Vetter
2020-10-31 14:45       ` Daniel Vetter
2020-11-01  5:22       ` John Hubbard
2020-11-01  5:22         ` John Hubbard
2020-11-01  5:22         ` John Hubbard
2020-11-01 10:30         ` Daniel Vetter
2020-11-01 10:30           ` Daniel Vetter
2020-11-01 10:30           ` Daniel Vetter
2020-11-01 21:13           ` John Hubbard
2020-11-01 21:13             ` John Hubbard
2020-11-01 21:13             ` John Hubbard
2020-11-01 22:50             ` Daniel Vetter
2020-11-01 22:50               ` Daniel Vetter
2020-11-01 22:50               ` Daniel Vetter
2020-11-04 14:00               ` Jason Gunthorpe
2020-11-04 14:00                 ` Jason Gunthorpe
2020-11-04 14:00                 ` Jason Gunthorpe
2020-11-04 15:54                 ` Daniel Vetter
2020-11-04 15:54                   ` Daniel Vetter
2020-11-04 15:54                   ` Daniel Vetter
2020-11-04 16:21                   ` Christoph Hellwig
2020-11-04 16:21                     ` Christoph Hellwig
2020-11-04 16:21                     ` Christoph Hellwig
2020-11-04 16:26                     ` Daniel Vetter
2020-11-04 16:26                       ` Daniel Vetter
2020-11-04 16:26                       ` Daniel Vetter
2020-11-04 16:26                       ` Daniel Vetter
2020-11-04 16:37                       ` Christoph Hellwig
2020-11-04 16:37                         ` Christoph Hellwig
2020-11-04 16:37                         ` Christoph Hellwig
2020-11-04 16:41                         ` Christoph Hellwig
2020-11-04 16:41                           ` Christoph Hellwig
2020-11-04 16:41                           ` Christoph Hellwig
2020-11-04 18:17                           ` Jason Gunthorpe
2020-11-04 18:17                             ` Jason Gunthorpe
2020-11-04 18:17                             ` Jason Gunthorpe
2020-11-04 18:17                             ` Jason Gunthorpe
2020-11-04 18:44                             ` John Hubbard
2020-11-04 18:44                               ` John Hubbard
2020-11-04 18:44                               ` John Hubbard
2020-11-04 18:44                               ` John Hubbard
2020-11-04 19:02                               ` Jason Gunthorpe
2020-11-04 19:02                                 ` Jason Gunthorpe
2020-11-04 19:02                                 ` Jason Gunthorpe
2020-11-04 19:02                                 ` Jason Gunthorpe
2020-11-04 19:11                                 ` Christoph Hellwig [this message]
2020-11-04 19:11                                   ` Christoph Hellwig
2020-11-04 19:11                                   ` Christoph Hellwig
2020-11-05  9:25                               ` Daniel Vetter
2020-11-05  9:25                                 ` Daniel Vetter
2020-11-05  9:25                                 ` Daniel Vetter
2020-11-05  9:25                                 ` Daniel Vetter
2020-11-05 12:49                                 ` Jason Gunthorpe
2020-11-05 12:49                                   ` Jason Gunthorpe
2020-11-05 12:49                                   ` Jason Gunthorpe
2020-11-05 12:49                                   ` Jason Gunthorpe
2020-11-06  4:08                                   ` John Hubbard
2020-11-06  4:08                                     ` John Hubbard
2020-11-06  4:08                                     ` John Hubbard
2020-11-06  4:08                                     ` John Hubbard
2020-11-06 10:01                                     ` Daniel Vetter
2020-11-06 10:01                                       ` Daniel Vetter
2020-11-06 10:01                                       ` Daniel Vetter
2020-11-06 10:01                                       ` Daniel Vetter
2020-11-06 10:27                                       ` Daniel Vetter
2020-11-06 10:27                                         ` Daniel Vetter
2020-11-06 10:27                                         ` Daniel Vetter
2020-11-06 10:27                                         ` Daniel Vetter
2020-11-06 12:55                                         ` Jason Gunthorpe
2020-11-06 12:55                                           ` Jason Gunthorpe
2020-11-06 12:55                                           ` Jason Gunthorpe
2020-11-06 12:55                                           ` Jason Gunthorpe
2020-11-09  8:44                                           ` Thomas Hellström
2020-11-09  8:44                                             ` Thomas Hellström
2020-11-09  8:44                                             ` Thomas Hellström
2020-11-09  8:44                                             ` Thomas Hellström
2020-11-09 20:19                                             ` Jason Gunthorpe
2020-11-09 20:19                                               ` Jason Gunthorpe
2020-11-09 20:19                                               ` Jason Gunthorpe
2020-11-09 20:19                                               ` Jason Gunthorpe
2020-11-06 12:58                                       ` Jason Gunthorpe
2020-11-06 12:58                                         ` Jason Gunthorpe
2020-11-06 12:58                                         ` Jason Gunthorpe
2020-11-06 12:58                                         ` Jason Gunthorpe
2020-10-30 10:08 ` [PATCH v5 06/15] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 07/15] mm: Close race in generic_access_phys Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 08/15] mm: Add unsafe_follow_pfn Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-11-02  7:29   ` Christoph Hellwig
2020-11-02  7:29     ` Christoph Hellwig
2020-11-02 12:56     ` Daniel Vetter
2020-11-02 12:56       ` Daniel Vetter
2020-11-02 12:56       ` Daniel Vetter
2020-11-02 12:56       ` Daniel Vetter
2020-11-02 13:01       ` Jason Gunthorpe
2020-11-02 13:01         ` Jason Gunthorpe
2020-11-02 13:01         ` Jason Gunthorpe
2020-11-02 13:01         ` Jason Gunthorpe
2020-11-02 13:23         ` Daniel Vetter
2020-11-02 13:23           ` Daniel Vetter
2020-11-02 13:23           ` Daniel Vetter
2020-11-02 13:23           ` Daniel Vetter
2020-11-02 15:52           ` Jason Gunthorpe
2020-11-02 15:52             ` Jason Gunthorpe
2020-11-02 15:52             ` Jason Gunthorpe
2020-11-02 15:52             ` Jason Gunthorpe
2020-11-02 16:41             ` Christoph Hellwig
2020-11-02 16:41               ` Christoph Hellwig
2020-11-02 16:41               ` Christoph Hellwig
2020-11-02 16:42             ` Daniel Vetter
2020-11-02 16:42               ` Daniel Vetter
2020-11-02 16:42               ` Daniel Vetter
2020-11-02 16:42               ` Daniel Vetter
2020-11-02 17:16               ` Jason Gunthorpe
2020-11-02 17:16                 ` Jason Gunthorpe
2020-11-02 17:16                 ` Jason Gunthorpe
2020-11-02 17:16                 ` Jason Gunthorpe
2020-10-30 10:08 ` [PATCH v5 09/15] media/videbuf1|2: Mark follow_pfn usage as unsafe Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 10/15] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 11/15] PCI: Obey iomem restrictions for procfs mmap Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-11-03 21:28   ` Bjorn Helgaas
2020-11-03 21:28     ` Bjorn Helgaas
2020-11-03 21:28     ` Bjorn Helgaas
2020-11-03 22:09     ` Dan Williams
2020-11-03 22:09       ` Dan Williams
2020-11-03 22:09       ` Dan Williams
2020-11-04  8:44       ` Daniel Vetter
2020-11-04  8:44         ` Daniel Vetter
2020-11-04  8:44         ` Daniel Vetter
2020-11-04 16:50         ` Bjorn Helgaas
2020-11-04 16:50           ` Bjorn Helgaas
2020-11-04 16:50           ` Bjorn Helgaas
2020-11-04 20:12           ` Dan Williams
2020-11-04 20:12             ` Dan Williams
2020-11-04 20:12             ` Dan Williams
2020-11-05  9:34             ` Daniel Vetter
2020-11-05  9:34               ` Daniel Vetter
2020-11-05  9:34               ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 12/15] /dev/mem: Only set filp->f_mapping Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 13/15] resource: Move devmem revoke code to resource framework Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-31  6:36   ` John Hubbard
2020-10-31  6:36     ` John Hubbard
2020-10-31  6:36     ` John Hubbard
2020-10-31 14:40     ` Daniel Vetter
2020-10-31 14:40       ` Daniel Vetter
2020-10-31 14:40       ` Daniel Vetter
2020-11-03  6:06   ` [resource] 22b17dc667: Kernel panic - not syncing: Fatal exception lkp
2020-11-03  6:06     ` lkp
2020-11-03  6:15     ` John Hubbard
2020-11-03  6:15       ` John Hubbard
2020-11-03  6:15       ` John Hubbard
2020-11-03 10:10       ` Daniel Vetter
2020-11-03 10:10         ` Daniel Vetter
2020-11-03 10:10         ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 14/15] sysfs: Support zapping of binary attr mmaps Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08 ` [PATCH v5 15/15] PCI: Revoke mappings like devmem Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 10:08   ` Daniel Vetter
2020-10-30 19:22   ` Dan Williams
2020-10-30 19:22     ` Dan Williams
2020-10-30 19:22     ` Dan Williams
2020-11-03 21:30   ` Bjorn Helgaas
2020-11-03 21:30     ` Bjorn Helgaas
2020-11-03 21:30     ` Bjorn Helgaas

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