From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jason Gunthorpe <jgg@nvidia.com>, Clint Sbisa <csbisa@amazon.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
linux-arm-kernel@lists.infradead.org, will@kernel.org,
catalin.marinas@arm.com, Leon Romanovsky <leon@kernel.org>
Subject: Re: [PATCH] arm64: Enable PCI write-combine resources under sysfs
Date: Tue, 15 Sep 2020 07:42:43 +1000 [thread overview]
Message-ID: <375c478593945a416f3180c3773bcb5240d2e36c.camel@kernel.crashing.org> (raw)
In-Reply-To: <20200914143819.GC904879@nvidia.com>
On Mon, 2020-09-14 at 11:38 -0300, Jason Gunthorpe wrote:
> On Mon, Sep 14, 2020 at 02:24:06PM +0000, Clint Sbisa wrote:
> > On Mon, Sep 14, 2020 at 11:17:26AM -0300, Jason Gunthorpe wrote:
> > > On Fri, Sep 11, 2020 at 09:42:25PM +0000, Clint Sbisa wrote:
> > >
> > > > There's no DMA involved with this BAR-- the driver writes a
> > > > portion of the
> > > > packet contents in addition to the descriptors, which generally
> > > > increases the
> > > > number of TLPs if write-combine isn't used. Furthermore, this
> > > > BAR is only used
> > > > for writes and never for reads.
> > >
> > > You use DPDK without DMA? How does receive work?
> >
> > That was not worded well. DMA is used, but the first X bytes of the
> > packet are
> > written directly to this BAR instead of being DMA'd-- the rest of
> > the data is
> > DMA'd.
>
> which is back to my original question, how do you do DMA using
> /sys/xx/resources? Why not use VFIO like everything else?
Note: All this doesnt' change the fact that sys/xx/resources_wc exists
for other archs and I see no reasons so far not to have it on ARM...
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jason Gunthorpe <jgg@nvidia.com>, Clint Sbisa <csbisa@amazon.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Leon Romanovsky <leon@kernel.org>,
linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: Enable PCI write-combine resources under sysfs
Date: Tue, 15 Sep 2020 07:42:43 +1000 [thread overview]
Message-ID: <375c478593945a416f3180c3773bcb5240d2e36c.camel@kernel.crashing.org> (raw)
In-Reply-To: <20200914143819.GC904879@nvidia.com>
On Mon, 2020-09-14 at 11:38 -0300, Jason Gunthorpe wrote:
> On Mon, Sep 14, 2020 at 02:24:06PM +0000, Clint Sbisa wrote:
> > On Mon, Sep 14, 2020 at 11:17:26AM -0300, Jason Gunthorpe wrote:
> > > On Fri, Sep 11, 2020 at 09:42:25PM +0000, Clint Sbisa wrote:
> > >
> > > > There's no DMA involved with this BAR-- the driver writes a
> > > > portion of the
> > > > packet contents in addition to the descriptors, which generally
> > > > increases the
> > > > number of TLPs if write-combine isn't used. Furthermore, this
> > > > BAR is only used
> > > > for writes and never for reads.
> > >
> > > You use DPDK without DMA? How does receive work?
> >
> > That was not worded well. DMA is used, but the first X bytes of the
> > packet are
> > written directly to this BAR instead of being DMA'd-- the rest of
> > the data is
> > DMA'd.
>
> which is back to my original question, how do you do DMA using
> /sys/xx/resources? Why not use VFIO like everything else?
Note: All this doesnt' change the fact that sys/xx/resources_wc exists
for other archs and I see no reasons so far not to have it on ARM...
Cheers,
Ben.
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next prev parent reply other threads:[~2020-09-14 21:43 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 15:18 [PATCH] arm64: Enable PCI write-combine resources under sysfs Clint Sbisa
2020-08-31 23:24 ` Benjamin Herrenschmidt
2020-09-01 18:37 ` Bjorn Helgaas
2020-09-01 23:22 ` Benjamin Herrenschmidt
2020-09-02 8:57 ` Will Deacon
2020-09-02 11:32 ` Lorenzo Pieralisi
2020-09-02 14:29 ` Clint Sbisa
2020-09-02 16:47 ` Lorenzo Pieralisi
2020-09-02 16:47 ` Lorenzo Pieralisi
2020-09-02 17:21 ` Catalin Marinas
2020-09-02 17:21 ` Catalin Marinas
2020-09-02 17:54 ` Lorenzo Pieralisi
2020-09-02 17:54 ` Lorenzo Pieralisi
2020-09-02 23:03 ` Benjamin Herrenschmidt
2020-09-02 23:03 ` Benjamin Herrenschmidt
2020-09-02 23:08 ` Benjamin Herrenschmidt
2020-09-02 23:08 ` Benjamin Herrenschmidt
2020-09-02 23:08 ` Benjamin Herrenschmidt
2020-09-02 23:08 ` Benjamin Herrenschmidt
2020-09-02 23:07 ` Benjamin Herrenschmidt
2020-09-02 23:07 ` Benjamin Herrenschmidt
2020-09-03 11:08 ` Lorenzo Pieralisi
2020-09-03 11:08 ` Lorenzo Pieralisi
2020-09-03 14:36 ` Clint Sbisa
2020-09-03 14:36 ` Clint Sbisa
2020-09-03 22:26 ` Benjamin Herrenschmidt
2020-09-03 22:26 ` Benjamin Herrenschmidt
2020-09-07 23:33 ` Benjamin Herrenschmidt
2020-09-07 23:33 ` Benjamin Herrenschmidt
2020-09-10 9:46 ` Lorenzo Pieralisi
2020-09-10 9:46 ` Lorenzo Pieralisi
2020-09-10 10:54 ` Leon Romanovsky
2020-09-10 10:54 ` Leon Romanovsky
2020-09-10 12:37 ` Jason Gunthorpe
2020-09-10 12:37 ` Jason Gunthorpe
2020-09-10 15:17 ` Lorenzo Pieralisi
2020-09-10 15:17 ` Lorenzo Pieralisi
2020-09-10 17:10 ` Jason Gunthorpe
2020-09-10 17:10 ` Jason Gunthorpe
2020-09-10 21:46 ` Benjamin Herrenschmidt
2020-09-10 21:46 ` Benjamin Herrenschmidt
2020-09-10 23:29 ` Jason Gunthorpe
2020-09-10 23:29 ` Jason Gunthorpe
2020-09-11 0:39 ` Benjamin Herrenschmidt
2020-09-11 0:39 ` Benjamin Herrenschmidt
2020-09-11 14:21 ` Jason Gunthorpe
2020-09-11 14:21 ` Jason Gunthorpe
2020-09-11 21:42 ` Clint Sbisa
2020-09-11 21:42 ` Clint Sbisa
2020-09-14 14:17 ` Jason Gunthorpe
2020-09-14 14:17 ` Jason Gunthorpe
2020-09-14 14:24 ` Clint Sbisa
2020-09-14 14:24 ` Clint Sbisa
2020-09-14 14:38 ` Jason Gunthorpe
2020-09-14 14:38 ` Jason Gunthorpe
2020-09-14 21:42 ` Benjamin Herrenschmidt [this message]
2020-09-14 21:42 ` Benjamin Herrenschmidt
2020-09-14 22:00 ` Benjamin Herrenschmidt
2020-09-14 22:00 ` Benjamin Herrenschmidt
2020-09-14 22:32 ` Clint Sbisa
2020-09-14 22:32 ` Clint Sbisa
2020-09-14 22:57 ` Jason Gunthorpe
2020-09-14 22:57 ` Jason Gunthorpe
2020-09-14 23:25 ` Benjamin Herrenschmidt
2020-09-14 23:25 ` Benjamin Herrenschmidt
2020-09-15 10:18 ` Lorenzo Pieralisi
2020-09-15 10:18 ` Lorenzo Pieralisi
2020-09-15 11:05 ` Jason Gunthorpe
2020-09-15 11:05 ` Jason Gunthorpe
2020-09-15 23:17 ` Benjamin Herrenschmidt
2020-09-15 23:17 ` Benjamin Herrenschmidt
2020-09-15 23:40 ` Jason Gunthorpe
2020-09-15 23:40 ` Jason Gunthorpe
2020-09-16 7:59 ` Benjamin Herrenschmidt
2020-09-16 7:59 ` Benjamin Herrenschmidt
2020-09-16 12:12 ` Jason Gunthorpe
2020-09-16 12:12 ` Jason Gunthorpe
2020-09-16 14:09 ` Lorenzo Pieralisi
2020-09-16 14:09 ` Lorenzo Pieralisi
2020-09-16 14:14 ` Jason Gunthorpe
2020-09-16 14:14 ` Jason Gunthorpe
2020-09-16 23:59 ` Benjamin Herrenschmidt
2020-09-16 23:59 ` Benjamin Herrenschmidt
2020-09-17 10:28 ` Lorenzo Pieralisi
2020-09-17 10:28 ` Lorenzo Pieralisi
2020-09-17 11:32 ` Jason Gunthorpe
2020-09-17 11:32 ` Jason Gunthorpe
2020-09-17 14:01 ` Lorenzo Pieralisi
2020-09-17 14:01 ` Lorenzo Pieralisi
2020-09-17 16:08 ` Will Deacon
2020-09-17 16:08 ` Will Deacon
2020-09-16 12:48 ` Leon Romanovsky
2020-09-16 12:48 ` Leon Romanovsky
2020-09-16 8:33 ` Will Deacon
2020-09-16 8:33 ` Will Deacon
2020-09-16 8:48 ` Catalin Marinas
2020-09-16 8:48 ` Catalin Marinas
2020-09-16 14:15 ` Lorenzo Pieralisi
2020-09-16 14:15 ` Lorenzo Pieralisi
2020-09-16 17:00 ` Catalin Marinas
2020-09-16 17:00 ` Catalin Marinas
2020-09-16 21:29 ` Benjamin Herrenschmidt
2020-09-16 21:29 ` Benjamin Herrenschmidt
2020-09-16 12:08 ` Jason Gunthorpe
2020-09-16 12:08 ` Jason Gunthorpe
2020-09-15 23:00 ` Benjamin Herrenschmidt
2020-09-15 23:00 ` Benjamin Herrenschmidt
2020-09-15 23:12 ` Clint Sbisa
2020-09-15 23:12 ` Clint Sbisa
2020-09-14 21:41 ` Benjamin Herrenschmidt
2020-09-14 21:41 ` Benjamin Herrenschmidt
-- strict thread matches above, loose matches on Subject: below --
2020-08-21 15:51 Clint Sbisa
2020-08-21 15:51 ` Clint Sbisa
2020-08-27 14:41 ` Clint Sbisa
2020-08-27 14:41 ` Clint Sbisa
2020-08-31 15:22 ` Clint Sbisa
2020-08-31 15:22 ` Clint Sbisa
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