From: Logan Gunthorpe <logang@deltatee.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
platform-driver-x86@vger.kernel.org, linux-mm@kvack.org,
Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
linux-s390@vger.kernel.org, David Hildenbrand <david@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Dan Williams <dan.j.williams@intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Michal Hocko <mhocko@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Eric Badger <ebadger@gigaio.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA
Date: Thu, 27 Feb 2020 17:21:50 +0000 [thread overview]
Message-ID: <e8781f85-3fc7-b9ce-c751-606803cbdc77@deltatee.com> (raw)
In-Reply-To: <20200227171704.GK31668@ziepe.ca>
On 2020-02-27 10:17 a.m., Jason Gunthorpe wrote:
>> Instead of this, this series proposes a change to arch_add_memory()
>> to take the pgprot required by the mapping which allows us to
>> explicitly set pagetable entries for P2PDMA memory to WC.
>
> Is there a particular reason why WC was selected here? I thought for
> the p2pdma cases there was no kernel user that touched the memory?
Yes, that's correct. I choose WC here because the existing users are
registering memory blocks without side effects which fit the WC
semantics well.
> I definitely forsee devices where we want UC instead.
Yes. My expectation is that once we have a kernel user that needs this,
we'd wire the option through struct dev_pagemap so the caller can choose
the mapping that makes sense.
Logan
WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, platform-driver-x86@vger.kernel.org,
linux-mm@kvack.org, Dan Williams <dan.j.williams@intel.com>,
Michal Hocko <mhocko@kernel.org>,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Eric Badger <ebadger@gigaio.com>
Subject: Re: [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA
Date: Thu, 27 Feb 2020 10:21:50 -0700 [thread overview]
Message-ID: <e8781f85-3fc7-b9ce-c751-606803cbdc77@deltatee.com> (raw)
In-Reply-To: <20200227171704.GK31668@ziepe.ca>
On 2020-02-27 10:17 a.m., Jason Gunthorpe wrote:
>> Instead of this, this series proposes a change to arch_add_memory()
>> to take the pgprot required by the mapping which allows us to
>> explicitly set pagetable entries for P2PDMA memory to WC.
>
> Is there a particular reason why WC was selected here? I thought for
> the p2pdma cases there was no kernel user that touched the memory?
Yes, that's correct. I choose WC here because the existing users are
registering memory blocks without side effects which fit the WC
semantics well.
> I definitely forsee devices where we want UC instead.
Yes. My expectation is that once we have a kernel user that needs this,
we'd wire the option through struct dev_pagemap so the caller can choose
the mapping that makes sense.
Logan
WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, platform-driver-x86@vger.kernel.org,
linux-mm@kvack.org, Dan Williams <dan.j.williams@intel.com>,
Michal Hocko <mhocko@kernel.org>,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA
Date: Thu, 27 Feb 2020 10:21:50 -0700 [thread overview]
Message-ID: <e8781f85-3fc7-b9ce-c751-606803cbdc77@deltatee.com> (raw)
In-Reply-To: <20200227171704.GK31668@ziepe.ca>
On 2020-02-27 10:17 a.m., Jason Gunthorpe wrote:
>> Instead of this, this series proposes a change to arch_add_memory()
>> to take the pgprot required by the mapping which allows us to
>> explicitly set pagetable entries for P2PDMA memory to WC.
>
> Is there a particular reason why WC was selected here? I thought for
> the p2pdma cases there was no kernel user that touched the memory?
Yes, that's correct. I choose WC here because the existing users are
registering memory blocks without side effects which fit the WC
semantics well.
> I definitely forsee devices where we want UC instead.
Yes. My expectation is that once we have a kernel user that needs this,
we'd wire the option through struct dev_pagemap so the caller can choose
the mapping that makes sense.
Logan
WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
platform-driver-x86@vger.kernel.org, linux-mm@kvack.org,
Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
linux-s390@vger.kernel.org, David Hildenbrand <david@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Michal Hocko <mhocko@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Eric Badger <ebadger@gigaio.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA
Date: Thu, 27 Feb 2020 10:21:50 -0700 [thread overview]
Message-ID: <e8781f85-3fc7-b9ce-c751-606803cbdc77@deltatee.com> (raw)
In-Reply-To: <20200227171704.GK31668@ziepe.ca>
On 2020-02-27 10:17 a.m., Jason Gunthorpe wrote:
>> Instead of this, this series proposes a change to arch_add_memory()
>> to take the pgprot required by the mapping which allows us to
>> explicitly set pagetable entries for P2PDMA memory to WC.
>
> Is there a particular reason why WC was selected here? I thought for
> the p2pdma cases there was no kernel user that touched the memory?
Yes, that's correct. I choose WC here because the existing users are
registering memory blocks without side effects which fit the WC
semantics well.
> I definitely forsee devices where we want UC instead.
Yes. My expectation is that once we have a kernel user that needs this,
we'd wire the option through struct dev_pagemap so the caller can choose
the mapping that makes sense.
Logan
WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
platform-driver-x86@vger.kernel.org, linux-mm@kvack.org,
Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
linux-s390@vger.kernel.org, David Hildenbrand <david@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Dan Williams <dan.j.williams@intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Michal Hocko <mhocko@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Eric Badger <ebadger@gigaio.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA
Date: Thu, 27 Feb 2020 10:21:50 -0700 [thread overview]
Message-ID: <e8781f85-3fc7-b9ce-c751-606803cbdc77@deltatee.com> (raw)
In-Reply-To: <20200227171704.GK31668@ziepe.ca>
On 2020-02-27 10:17 a.m., Jason Gunthorpe wrote:
>> Instead of this, this series proposes a change to arch_add_memory()
>> to take the pgprot required by the mapping which allows us to
>> explicitly set pagetable entries for P2PDMA memory to WC.
>
> Is there a particular reason why WC was selected here? I thought for
> the p2pdma cases there was no kernel user that touched the memory?
Yes, that's correct. I choose WC here because the existing users are
registering memory blocks without side effects which fit the WC
semantics well.
> I definitely forsee devices where we want UC instead.
Yes. My expectation is that once we have a kernel user that needs this,
we'd wire the option through struct dev_pagemap so the caller can choose
the mapping that makes sense.
Logan
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-02-27 17:21 UTC|newest]
Thread overview: 148+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 18:24 [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` [PATCH v3 1/7] mm/memory_hotplug: Drop the flags field from struct mhp_restrictions Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-28 21:31 ` Dan Williams
2020-02-28 21:31 ` Dan Williams
2020-02-28 21:31 ` Dan Williams
2020-02-28 21:31 ` Dan Williams
2020-02-28 21:31 ` Dan Williams
2020-02-28 21:31 ` Dan Williams
2020-03-03 9:50 ` Michal Hocko
2020-03-03 9:50 ` Michal Hocko
2020-03-03 9:50 ` Michal Hocko
2020-03-03 9:50 ` Michal Hocko
2020-02-21 18:24 ` [PATCH v3 2/7] mm/memory_hotplug: Rename mhp_restrictions to mhp_params Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-24 9:11 ` David Hildenbrand
2020-02-24 9:11 ` David Hildenbrand
2020-02-24 9:11 ` David Hildenbrand
2020-02-24 9:11 ` David Hildenbrand
2020-02-29 20:44 ` Dan Williams
2020-02-29 20:44 ` Dan Williams
2020-02-29 20:44 ` Dan Williams
2020-02-29 20:44 ` Dan Williams
2020-02-29 20:44 ` Dan Williams
2020-02-29 20:44 ` Dan Williams
2020-03-03 9:50 ` Michal Hocko
2020-03-03 9:50 ` Michal Hocko
2020-03-03 9:50 ` Michal Hocko
2020-03-03 9:50 ` Michal Hocko
2020-02-21 18:24 ` [PATCH v3 3/7] x86/mm: Thread pgprot_t through init_memory_mapping() Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-21 18:24 ` Logan Gunthorpe
2020-02-29 22:37 ` Dan Williams
2020-02-29 22:37 ` Dan Williams
2020-02-29 22:37 ` Dan Williams
2020-02-29 22:37 ` Dan Williams
2020-02-29 22:37 ` Dan Williams
2020-02-29 22:37 ` Dan Williams
2020-03-03 9:52 ` Michal Hocko
2020-03-03 9:52 ` Michal Hocko
2020-03-03 9:52 ` Michal Hocko
2020-03-03 9:52 ` Michal Hocko
2020-03-03 9:52 ` Michal Hocko
2020-02-21 18:25 ` [PATCH v3 4/7] x86/mm: Introduce _set_memory_prot() Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-29 22:33 ` Dan Williams
2020-02-29 22:33 ` Dan Williams
2020-02-29 22:33 ` Dan Williams
2020-02-29 22:33 ` Dan Williams
2020-02-29 22:33 ` Dan Williams
2020-02-29 22:33 ` Dan Williams
2020-03-02 18:46 ` Logan Gunthorpe
2020-03-02 18:46 ` Logan Gunthorpe
2020-03-02 18:46 ` Logan Gunthorpe
2020-03-02 18:46 ` Logan Gunthorpe
2020-03-02 18:46 ` Logan Gunthorpe
2020-02-21 18:25 ` [PATCH v3 5/7] powerpc/mm: Thread pgprot_t through create_section_mapping() Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` [PATCH v3 6/7] mm/memory_hotplug: Add pgprot_t to mhp_params Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-24 9:26 ` David Hildenbrand
2020-02-24 9:26 ` David Hildenbrand
2020-02-24 9:26 ` David Hildenbrand
2020-02-24 9:26 ` David Hildenbrand
2020-02-29 22:44 ` Dan Williams
2020-02-29 22:44 ` Dan Williams
2020-02-29 22:44 ` Dan Williams
2020-02-29 22:44 ` Dan Williams
2020-02-29 22:44 ` Dan Williams
2020-02-29 22:44 ` Dan Williams
2020-03-02 18:55 ` Logan Gunthorpe
2020-03-02 18:55 ` Logan Gunthorpe
2020-03-02 18:55 ` Logan Gunthorpe
2020-03-02 18:55 ` Logan Gunthorpe
2020-03-02 18:55 ` Logan Gunthorpe
2020-03-02 20:26 ` Dan Williams
2020-03-02 20:26 ` Dan Williams
2020-03-02 20:26 ` Dan Williams
2020-03-02 20:26 ` Dan Williams
2020-03-02 20:26 ` Dan Williams
2020-03-02 20:26 ` Dan Williams
2020-02-21 18:25 ` [PATCH v3 7/7] mm/memremap: Set caching mode for PCI P2PDMA memory to WC Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-21 18:25 ` Logan Gunthorpe
2020-02-29 22:47 ` Dan Williams
2020-02-29 22:47 ` Dan Williams
2020-02-29 22:47 ` Dan Williams
2020-02-29 22:47 ` Dan Williams
2020-02-29 22:47 ` Dan Williams
2020-02-29 22:47 ` Dan Williams
2020-03-02 21:20 ` Logan Gunthorpe
2020-03-02 21:20 ` Logan Gunthorpe
2020-03-02 21:20 ` Logan Gunthorpe
2020-03-02 21:20 ` Logan Gunthorpe
2020-03-02 21:20 ` Logan Gunthorpe
2020-02-27 17:17 ` [PATCH v3 0/7] Allow setting caching mode in arch_add_memory() for P2PDMA Jason Gunthorpe
2020-02-27 17:17 ` Jason Gunthorpe
2020-02-27 17:17 ` Jason Gunthorpe
2020-02-27 17:17 ` Jason Gunthorpe
2020-02-27 17:17 ` Jason Gunthorpe
2020-02-27 17:21 ` Logan Gunthorpe [this message]
2020-02-27 17:21 ` Logan Gunthorpe
2020-02-27 17:21 ` Logan Gunthorpe
2020-02-27 17:21 ` Logan Gunthorpe
2020-02-27 17:21 ` Logan Gunthorpe
2020-02-27 17:43 ` Jason Gunthorpe
2020-02-27 17:43 ` Jason Gunthorpe
2020-02-27 17:43 ` Jason Gunthorpe
2020-02-27 17:43 ` Jason Gunthorpe
2020-02-27 17:43 ` Jason Gunthorpe
2020-02-27 17:54 ` Logan Gunthorpe
2020-02-27 17:54 ` Logan Gunthorpe
2020-02-27 17:54 ` Logan Gunthorpe
2020-02-27 17:54 ` Logan Gunthorpe
2020-02-27 17:54 ` Logan Gunthorpe
2020-02-27 17:55 ` Dan Williams
2020-02-27 17:55 ` Dan Williams
2020-02-27 17:55 ` Dan Williams
2020-02-27 17:55 ` Dan Williams
2020-02-27 17:55 ` Dan Williams
2020-02-27 17:55 ` Dan Williams
2020-02-27 18:03 ` Jason Gunthorpe
2020-02-27 18:03 ` Jason Gunthorpe
2020-02-27 18:03 ` Jason Gunthorpe
2020-02-27 18:03 ` Jason Gunthorpe
2020-02-27 18:03 ` Jason Gunthorpe
2020-02-27 18:08 ` Dan Williams
2020-02-27 18:08 ` Dan Williams
2020-02-27 18:08 ` Dan Williams
2020-02-27 18:08 ` Dan Williams
2020-02-27 18:08 ` Dan Williams
2020-02-27 18:08 ` Dan Williams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e8781f85-3fc7-b9ce-c751-606803cbdc77@deltatee.com \
--to=logang@deltatee.com \
--cc=akpm@linux-foundation.org \
--cc=benh@kernel.crashing.org \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=ebadger@gigaio.com \
--cc=hch@lst.de \
--cc=jgg@ziepe.ca \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=luto@kernel.org \
--cc=mhocko@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=platform-driver-x86@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.