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From: Christoph Hellwig <hch@lst.de>
To: "Koenig, Christian" <Christian.Koenig@amd.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
	Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>,
	"Maciej W. Rozycki" <macro@linux-mips.org>,
	Eric Biggers <ebiggers@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Imre Deak <imre.deak@intel.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Benjamin Gaignard <benjamin.gaignard@linaro.org>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
	Emil Velikov <emil.velikov@collabora.com>,
	Rob Clark <robdclark@chromium.org>,
	Paul Burton <paul.burton@mips.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	"moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)"
	<linux-arm-kernel@lists.infradead.org>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	"open list:MIPS" <linux-mips@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU"
	<linux-arm-msm@vger.kernel.org>,
	"Sharma, Deepak" <Deepak.Sharma@amd.com>,
	Joerg Roedel <jroedel@suse.de>, Arnd Bergmann <arnd@arndb.de>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Hauke Mehrtens <hauke@hauke-m.de>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	"Wolfram Sang \(Renesas\)" <wsa+renesas@sang-engineering.com>,
	"open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)"
	<linuxppc-dev@lists.ozlabs.org>,
	Alexios Zavras <alexios.zavras@intel.com>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Doug Anderson <armlinux@m.disordat.com>,
	Thomas Gleixner <tglx@linutronix.de>, Sean Paul <sean@poorly.run>,
	Allison Randal <allison@lohutok.net>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Enrico Weigelt <info@metux.net>,
	open list <linux-kernel@vger.kernel.org>,
	Rob Clark <robdclark@gmail.com>,
	Souptick Joarder <jrdr.linux@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU"
	<freedreno@lists.freedesktop.org>
Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc
Date: Thu, 15 Aug 2019 20:52:00 +0200	[thread overview]
Message-ID: <20190815185200.GA21407@lst.de> (raw)
In-Reply-To: <215e5cb7-0fcf-48db-a656-817054dde420@email.android.com>

On Thu, Aug 15, 2019 at 06:48:39PM +0000, Koenig, Christian wrote:
> Well, for the graphics case I absolutely need to keep the linear kernel mapping. Because for certain use cases the memory is accessed by the kernel all the time as well.

Then don't set DMA_ATTR_NO_KERNEL_MAPPING.  At least for x86 and arm64
we should be able to support uncached allocations easily even without
that, and I plan to support that for your use case.  But if the driver
is explicitly saying it doesn't want a permanent kernel mapping it makes
sense to (optionally if the architecture can easily do it) unmap the
memory from the kernel linear mapping.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: "Koenig, Christian" <Christian.Koenig@amd.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
	Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>,
	"Maciej W. Rozycki" <macro@linux-mips.org>,
	Eric Biggers <ebiggers@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Imre Deak <imre.deak@intel.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Benjamin Gaignard <benjamin.gaignard@linaro.org>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
	Emil Velikov <emil.velikov@collabora.com>,
	Rob Clark <robdclark@chromium.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Paul Burton <paul.burton@mips.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	"moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)"
	<linux-arm-kernel@lists.infradead.org>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	"open list:MIPS" <linux-mips@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU"
	<linux-arm-msm@vger.kernel.org>,
	"Sharma, Deepak" <Deepak.Sharma@amd.com>,
	Joerg Roedel <jroedel@suse.de>, Arnd Bergmann <arnd@arndb.de>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Hauke Mehrtens <hauke@hauke-m.de>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	"Wolfram Sang \(Renesas\)" <wsa+renesas@sang-engineering.com>,
	"open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)"
	<linuxppc-dev@lists.ozlabs.org>,
	Alexios Zavras <alexios.zavras@intel.com>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Doug Anderson <armlinux@m.disordat.com>,
	Thomas Gleixner <tglx@linutronix.de>, Sean Paul <sean@poorly.run>,
	Allison Randal <allison@lohutok.net>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Enrico Weigelt <info@metux.net>,
	open list <linux-kernel@vger.kernel.org>,
	Rob Clark <robdclark@gmail.com>,
	Souptick Joarder <jrdr.linux@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU"
	<freedreno@lists.freedesktop.org>
Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc
Date: Thu, 15 Aug 2019 20:52:00 +0200	[thread overview]
Message-ID: <20190815185200.GA21407@lst.de> (raw)
In-Reply-To: <215e5cb7-0fcf-48db-a656-817054dde420@email.android.com>

On Thu, Aug 15, 2019 at 06:48:39PM +0000, Koenig, Christian wrote:
> Well, for the graphics case I absolutely need to keep the linear kernel mapping. Because for certain use cases the memory is accessed by the kernel all the time as well.

Then don't set DMA_ATTR_NO_KERNEL_MAPPING.  At least for x86 and arm64
we should be able to support uncached allocations easily even without
that, and I plan to support that for your use case.  But if the driver
is explicitly saying it doesn't want a permanent kernel mapping it makes
sense to (optionally if the architecture can easily do it) unmap the
memory from the kernel linear mapping.

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

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: "Koenig, Christian" <Christian.Koenig-5C7GfCeVMHo@public.gmane.org>
Cc: Kate Stewart
	<kstewart-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	Masayoshi Mizuma
	<m.mizuma-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
	"Maciej W. Rozycki"
	<macro-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>,
	Eric Biggers <ebiggers-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>,
	Imre Deak <imre.deak-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	dri-devel
	<dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	Chris Wilson
	<chris-Y6uKTt2uX1cEflXRtASbqLVCufUGDwFn@public.gmane.org>,
	Masahiro Yamada
	<yamada.masahiro-uWyLwvC0a2jby3iVrkZq2A@public.gmane.org>,
	Benjamin Gaignard
	<benjamin.gaignard-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Mauro Carvalho Chehab
	<mchehab+samsung-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Will Deacon <will-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
	Emil Velikov
	<emil.velikov-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>,
	Rob Clark <robdclark-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
	Paul Burton <paul.burton-8NJIiSa5LzA@public.gmane.org>,
	Mike Rapoport <rppt-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>,
	Geert Uytterhoeven
	<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>,
	"moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	Daniel
Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc
Date: Thu, 15 Aug 2019 20:52:00 +0200	[thread overview]
Message-ID: <20190815185200.GA21407@lst.de> (raw)
In-Reply-To: <215e5cb7-0fcf-48db-a656-817054dde420-2ueSQiBKiTY7tOexoI0I+QC/G2K4zDHf@public.gmane.org>

On Thu, Aug 15, 2019 at 06:48:39PM +0000, Koenig, Christian wrote:
> Well, for the graphics case I absolutely need to keep the linear kernel mapping. Because for certain use cases the memory is accessed by the kernel all the time as well.

Then don't set DMA_ATTR_NO_KERNEL_MAPPING.  At least for x86 and arm64
we should be able to support uncached allocations easily even without
that, and I plan to support that for your use case.  But if the driver
is explicitly saying it doesn't want a permanent kernel mapping it makes
sense to (optionally if the architecture can easily do it) unmap the
memory from the kernel linear mapping.
_______________________________________________
Freedreno mailing list
Freedreno@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/freedreno

  reply	other threads:[~2019-08-15 18:54 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-15 18:48 [PATCH 0/6] drm+dma: cache support for arm, etc Koenig, Christian
2019-08-15 18:48 ` Koenig, Christian
2019-08-15 18:52 ` Christoph Hellwig [this message]
2019-08-15 18:52   ` Christoph Hellwig
2019-08-15 18:52   ` Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2019-08-14 21:59 Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-15  6:51 ` Christoph Hellwig
2019-08-15  6:51   ` Christoph Hellwig
2019-08-15  6:51   ` Christoph Hellwig
2019-08-15 13:54   ` Rob Clark
2019-08-15 13:54     ` Rob Clark
2019-08-15 13:54     ` Rob Clark
2019-08-15 17:53     ` Christoph Hellwig
2019-08-15 17:53       ` Christoph Hellwig
2019-08-15 17:53       ` Christoph Hellwig
2019-08-15 18:21       ` Koenig, Christian
2019-08-15 18:21         ` Koenig, Christian
2019-08-15 18:21         ` Koenig, Christian
2019-08-15 18:27         ` Christoph Hellwig
2019-08-15 18:27           ` Christoph Hellwig
2019-08-15 18:27           ` Christoph Hellwig
2019-08-16 21:04       ` Rob Clark
2019-08-16 21:04         ` Rob Clark
2019-08-16 21:04         ` Rob Clark
2019-08-19  5:23         ` Christoph Hellwig
2019-08-19  5:23           ` Christoph Hellwig
2019-08-19  5:23           ` Christoph Hellwig
2019-08-19 14:39           ` Rob Clark
2019-08-19 14:39             ` Rob Clark
2019-08-19 14:39             ` Rob Clark

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