From: Borislav Petkov <bp@alien8.de>
To: Dave Jiang <dave.jiang@intel.com>
Cc: "dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"vkoul@kernel.org" <vkoul@kernel.org>,
"Williams, Dan J" <dan.j.williams@intel.com>,
"Luck, Tony" <tony.luck@intel.com>,
"Lin, Jing" <jing.lin@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
"Dey, Megha" <megha.dey@intel.com>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
"Liu, Yi L" <yi.l.liu@intel.com>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
"hpa@zytor.com" <hpa@zytor.com>
Subject: Re: [PATCH RFC 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction
Date: Fri, 22 Nov 2019 09:59:53 +0100 [thread overview]
Message-ID: <20191122085953.GA6289@zn.tnic> (raw)
In-Reply-To: <ef6bc4a4-b307-9bc4-f3be-f7ab7232d303@intel.com>
On Thu, Nov 21, 2019 at 09:52:19AM -0700, Dave Jiang wrote:
> No what I mean was those primitives are missing the checks and we should
> probably address that at some point.
Oh, patches are always welcome! :)
> How would I detect that? Add a size (in bytes) parameter for the total
> source data?
Sure.
So, here's the deal: the more I look at this thing, the more I think
this iosubmit_cmds512() function should not be in a generic header but
in an intel-/driver-specific one. Why?
Well, movdir64b is Intel-only for now, you don't have a fallback
option for the platforms which do not support that insn and it is more
preferential for you to do the feature check once at driver init and
then call the function because you *know* you have movdir64b support
and not have any feature check in the function itself, not even a fast
static_cpu_has() one.
And this way you can do away with alignment and size checks because you
control what your driver does.
If it turns out that this function needs to be shared with other
platforms, then we can consider lifting it into a generic header and
making it more generic.
Ok?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2019-11-22 9:00 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 21:23 [PATCH RFC 00/14] idxd driver for Intel Data Streaming Accelerator Dave Jiang
2019-11-20 21:23 ` [PATCH RFC 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction Dave Jiang
2019-11-20 21:50 ` Dave Hansen
2019-11-20 23:46 ` Dave Jiang
2019-11-20 21:53 ` Borislav Petkov
2019-11-20 23:19 ` Luck, Tony
2019-11-20 23:26 ` Borislav Petkov
2019-11-21 0:15 ` Luck, Tony
2019-11-21 0:27 ` Dan Williams
2019-11-21 0:53 ` Thomas Gleixner
2019-11-21 1:32 ` Dan Williams
2019-11-21 10:37 ` Borislav Petkov
2019-11-21 0:21 ` Dan Williams
2019-11-21 0:22 ` Thomas Gleixner
2019-11-21 0:27 ` Dave Jiang
2019-11-21 0:10 ` Dave Jiang
2019-11-21 10:59 ` Borislav Petkov
2019-11-21 16:52 ` Dave Jiang
2019-11-22 8:59 ` Borislav Petkov [this message]
2019-11-22 17:20 ` Dan Williams
2019-11-22 18:44 ` Borislav Petkov
2019-11-22 18:50 ` Dan Williams
2019-11-20 21:23 ` [PATCH RFC 02/14] dmaengine: break out channel registration Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 03/14] dmaengine: add new dma device registration Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 04/14] mm: create common code from request allocation based from blk-mq code Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 05/14] dmaengine: add dma_request support functions Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 06/14] dmaengine: add dma request submit and completion path support Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 07/14] dmaengine: update dmatest to support dma request Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 08/14] dmaengine: idxd: Init and probe for Intel data accelerators Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 09/14] dmaengine: idxd: add configuration component of driver Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 10/14] dmaengine: idxd: add descriptor manipulation routines Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 11/14] dmaengine: idxd: connect idxd to dmaengine subsystem Dave Jiang
2019-11-20 21:24 ` [PATCH RFC 12/14] dmaengine: request submit optimization Dave Jiang
2019-11-20 21:25 ` [PATCH RFC 13/14] dmaengine: idxd: add char driver to expose submission portal to userland Dave Jiang
2019-11-20 21:25 ` [PATCH RFC 14/14] dmaengine: idxd: add sysfs ABI for idxd driver Dave Jiang
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