From: Arnd Bergmann <arnd@linaro.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
Simon Horman <horms@verge.net.au>,
linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
artemi.ivanov@cogentembedded.com,
Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>,
Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org
Subject: Re: NVMe vs DMA addressing limitations
Date: Tue, 10 Jan 2017 11:54:26 +0100 [thread overview]
Message-ID: <1967203.EWsxCL11oI@wuerfel> (raw)
In-Reply-To: <20170110070719.GA17208@lst.de>
On Tuesday, January 10, 2017 8:07:20 AM CET Christoph Hellwig wrote:
> On Tue, Jan 10, 2017 at 09:47:21AM +0300, Nikita Yushchenko wrote:
> > I'm now working with HW that:
> > - is now way "low end" or "obsolete", it has 4G of RAM and 8 CPU cores,
> > and is being manufactured and developed,
> > - has 75% of it's RAM located beyond first 4G of address space,
> > - can't physically handle incoming PCIe transactions addressed to memory
> > beyond 4G.
>
> It might not be low end or obselete, but it's absolutely braindead.
> Your I/O performance will suffer badly for the life of the platform
> because someone tries to save 2 cents, and there is not much we can do
> about it.
Unfortunately it is a common problem for arm64 chips that were designed
by taking a 32-bit SoC and replacing the CPU core. The swiotlb is the
right workaround for this, and I think we all agree that we should
just make it work correctly.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@linaro.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
Keith Busch <keith.busch@intel.com>,
Sagi Grimberg <sagi@grimberg.me>, Jens Axboe <axboe@fb.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-renesas-soc@vger.kernel.org,
Simon Horman <horms@verge.net.au>,
linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
artemi.ivanov@cogentembedded.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: NVMe vs DMA addressing limitations
Date: Tue, 10 Jan 2017 11:54:26 +0100 [thread overview]
Message-ID: <1967203.EWsxCL11oI@wuerfel> (raw)
In-Reply-To: <20170110070719.GA17208@lst.de>
On Tuesday, January 10, 2017 8:07:20 AM CET Christoph Hellwig wrote:
> On Tue, Jan 10, 2017 at 09:47:21AM +0300, Nikita Yushchenko wrote:
> > I'm now working with HW that:
> > - is now way "low end" or "obsolete", it has 4G of RAM and 8 CPU cores,
> > and is being manufactured and developed,
> > - has 75% of it's RAM located beyond first 4G of address space,
> > - can't physically handle incoming PCIe transactions addressed to memory
> > beyond 4G.
>
> It might not be low end or obselete, but it's absolutely braindead.
> Your I/O performance will suffer badly for the life of the platform
> because someone tries to save 2 cents, and there is not much we can do
> about it.
Unfortunately it is a common problem for arm64 chips that were designed
by taking a 32-bit SoC and replacing the CPU core. The swiotlb is the
right workaround for this, and I think we all agree that we should
just make it work correctly.
Arnd
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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: arnd@linaro.org (Arnd Bergmann)
Subject: NVMe vs DMA addressing limitations
Date: Tue, 10 Jan 2017 11:54:26 +0100 [thread overview]
Message-ID: <1967203.EWsxCL11oI@wuerfel> (raw)
In-Reply-To: <20170110070719.GA17208@lst.de>
On Tuesday, January 10, 2017 8:07:20 AM CET Christoph Hellwig wrote:
> On Tue, Jan 10, 2017@09:47:21AM +0300, Nikita Yushchenko wrote:
> > I'm now working with HW that:
> > - is now way "low end" or "obsolete", it has 4G of RAM and 8 CPU cores,
> > and is being manufactured and developed,
> > - has 75% of it's RAM located beyond first 4G of address space,
> > - can't physically handle incoming PCIe transactions addressed to memory
> > beyond 4G.
>
> It might not be low end or obselete, but it's absolutely braindead.
> Your I/O performance will suffer badly for the life of the platform
> because someone tries to save 2 cents, and there is not much we can do
> about it.
Unfortunately it is a common problem for arm64 chips that were designed
by taking a 32-bit SoC and replacing the CPU core. The swiotlb is the
right workaround for this, and I think we all agree that we should
just make it work correctly.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: arnd@linaro.org (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: NVMe vs DMA addressing limitations
Date: Tue, 10 Jan 2017 11:54:26 +0100 [thread overview]
Message-ID: <1967203.EWsxCL11oI@wuerfel> (raw)
In-Reply-To: <20170110070719.GA17208@lst.de>
On Tuesday, January 10, 2017 8:07:20 AM CET Christoph Hellwig wrote:
> On Tue, Jan 10, 2017 at 09:47:21AM +0300, Nikita Yushchenko wrote:
> > I'm now working with HW that:
> > - is now way "low end" or "obsolete", it has 4G of RAM and 8 CPU cores,
> > and is being manufactured and developed,
> > - has 75% of it's RAM located beyond first 4G of address space,
> > - can't physically handle incoming PCIe transactions addressed to memory
> > beyond 4G.
>
> It might not be low end or obselete, but it's absolutely braindead.
> Your I/O performance will suffer badly for the life of the platform
> because someone tries to save 2 cents, and there is not much we can do
> about it.
Unfortunately it is a common problem for arm64 chips that were designed
by taking a 32-bit SoC and replacing the CPU core. The swiotlb is the
right workaround for this, and I think we all agree that we should
just make it work correctly.
Arnd
next prev parent reply other threads:[~2017-01-10 10:54 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-29 20:45 [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Nikita Yushchenko
2016-12-29 20:45 ` Nikita Yushchenko
2016-12-29 20:45 ` [PATCH 2/2] rcar-pcie: set host bridge's " Nikita Yushchenko
2016-12-29 20:45 ` Nikita Yushchenko
2016-12-29 21:18 ` [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit " Arnd Bergmann
2017-02-16 16:12 ` Arnd Bergmann
2016-12-29 21:18 ` Arnd Bergmann
2016-12-30 9:46 ` Sergei Shtylyov
2016-12-30 9:46 ` Sergei Shtylyov
2016-12-30 10:06 ` Sergei Shtylyov
2016-12-30 10:06 ` Sergei Shtylyov
2017-01-03 18:44 ` Will Deacon
2017-01-03 18:44 ` Will Deacon
2017-01-03 19:00 ` Nikita Yushchenko
2017-01-03 19:00 ` Nikita Yushchenko
2017-01-03 19:01 ` Nikita Yushchenko
2017-01-03 19:01 ` Nikita Yushchenko
2017-01-03 19:01 ` Nikita Yushchenko
2017-01-03 20:13 ` Grygorii Strashko
2017-01-03 20:13 ` Grygorii Strashko
2017-01-03 20:13 ` Grygorii Strashko
2017-01-03 20:23 ` Nikita Yushchenko
2017-01-03 20:23 ` Nikita Yushchenko
2017-01-03 20:23 ` Nikita Yushchenko
2017-01-03 23:13 ` Arnd Bergmann
2017-01-03 23:13 ` Arnd Bergmann
2017-01-03 23:13 ` Arnd Bergmann
2017-01-04 6:24 ` Nikita Yushchenko
2017-01-04 6:24 ` Nikita Yushchenko
2017-01-04 6:24 ` Nikita Yushchenko
2017-01-04 13:29 ` Arnd Bergmann
2017-01-04 13:29 ` Arnd Bergmann
2017-01-04 13:29 ` Arnd Bergmann
2017-01-04 14:30 ` Nikita Yushchenko
2017-01-04 14:30 ` Nikita Yushchenko
2017-01-04 14:30 ` Nikita Yushchenko
2017-01-04 14:46 ` Arnd Bergmann
2017-01-04 14:46 ` Arnd Bergmann
2017-01-04 15:29 ` Nikita Yushchenko
2017-01-04 15:29 ` Nikita Yushchenko
2017-01-04 15:29 ` Nikita Yushchenko
2017-01-06 11:10 ` Arnd Bergmann
2017-01-06 11:10 ` Arnd Bergmann
2017-01-06 11:10 ` Arnd Bergmann
2017-01-06 13:47 ` Nikita Yushchenko
2017-01-06 13:47 ` Nikita Yushchenko
2017-01-06 13:47 ` Nikita Yushchenko
2017-01-06 14:38 ` [PATCH] arm64: do not set dma masks that device connection can't handle Nikita Yushchenko
2017-01-06 14:38 ` Nikita Yushchenko
2017-01-06 14:45 ` Nikita Yushchenko
2017-01-06 14:45 ` Nikita Yushchenko
2017-01-08 7:09 ` Sergei Shtylyov
2017-01-08 7:09 ` Sergei Shtylyov
2017-01-09 6:56 ` Nikita Yushchenko
2017-01-09 6:56 ` Nikita Yushchenko
2017-01-09 14:05 ` [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann
2017-01-09 14:05 ` Arnd Bergmann
2017-01-09 14:05 ` Arnd Bergmann
2017-01-09 20:34 ` Nikita Yushchenko
2017-01-09 20:34 ` Nikita Yushchenko
2017-01-09 20:34 ` Nikita Yushchenko
2017-01-09 20:34 ` Nikita Yushchenko
2017-01-09 20:57 ` Christoph Hellwig
2017-01-09 20:57 ` Christoph Hellwig
2017-01-09 20:57 ` Christoph Hellwig
2017-01-09 20:57 ` Christoph Hellwig
2017-01-10 6:47 ` NVMe vs DMA addressing limitations Nikita Yushchenko
2017-01-10 7:07 ` Christoph Hellwig
2017-01-10 7:07 ` Christoph Hellwig
2017-01-10 7:07 ` Christoph Hellwig
2017-01-10 7:07 ` Christoph Hellwig
2017-01-10 7:31 ` Nikita Yushchenko
2017-01-10 7:31 ` Nikita Yushchenko
2017-01-10 7:31 ` Nikita Yushchenko
2017-01-10 7:31 ` Nikita Yushchenko
2017-01-10 11:01 ` Arnd Bergmann
2017-01-10 11:01 ` Arnd Bergmann
2017-01-10 11:01 ` Arnd Bergmann
2017-01-10 11:01 ` Arnd Bergmann
2017-01-10 14:48 ` Christoph Hellwig
2017-01-10 14:48 ` Christoph Hellwig
2017-01-10 14:48 ` Christoph Hellwig
2017-01-10 14:48 ` Christoph Hellwig
2017-01-10 15:02 ` Arnd Bergmann
2017-01-10 15:02 ` Arnd Bergmann
2017-01-10 15:02 ` Arnd Bergmann
2017-01-10 15:02 ` Arnd Bergmann
2017-01-12 10:09 ` Sagi Grimberg
2017-01-12 10:09 ` Sagi Grimberg
2017-01-12 10:09 ` Sagi Grimberg
2017-01-12 10:09 ` Sagi Grimberg
2017-01-12 11:56 ` Arnd Bergmann
2017-01-12 11:56 ` Arnd Bergmann
2017-01-12 11:56 ` Arnd Bergmann
2017-01-12 11:56 ` Arnd Bergmann
2017-01-12 13:07 ` Christoph Hellwig
2017-01-12 13:07 ` Christoph Hellwig
2017-01-12 13:07 ` Christoph Hellwig
2017-01-12 13:07 ` Christoph Hellwig
2017-01-10 10:54 ` Arnd Bergmann [this message]
2017-01-10 10:54 ` Arnd Bergmann
2017-01-10 10:54 ` Arnd Bergmann
2017-01-10 10:54 ` Arnd Bergmann
2017-01-10 10:47 ` [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann
2017-01-10 10:47 ` Arnd Bergmann
2017-01-10 10:47 ` Arnd Bergmann
2017-01-10 10:47 ` Arnd Bergmann
2017-01-10 14:44 ` Christoph Hellwig
2017-01-10 14:44 ` Christoph Hellwig
2017-01-10 14:44 ` Christoph Hellwig
2017-01-10 14:44 ` Christoph Hellwig
2017-01-10 15:00 ` Arnd Bergmann
2017-01-10 15:00 ` Arnd Bergmann
2017-01-10 15:00 ` Arnd Bergmann
2017-01-10 15:00 ` Arnd Bergmann
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