linux-kernel - Re: [PATCH] Add 2-level GPUVM pagetables support to radeon driver.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 14 Sep 2012 10:49:19 +0200
From:	Christian König <deathsimple@...afone.de>
To:	Jerome Glisse <j.glisse@...il.com>
CC:	Alex Deucher <alexdeucher@...il.com>,
	Dmitry Cherkasov <Dmitrii.Cherkasov@....com>,
	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	Alex Deucher <alexander.deucher@....com>,
	Dave Airlie <airlied@...hat.com>,
	Dmitry Cherkasov <dcherkassov@...il.com>
Subject: Re: [PATCH] Add 2-level GPUVM pagetables support to radeon driver.

On 13.09.2012 20:42, Jerome Glisse wrote:
> On Thu, Sep 13, 2012 at 2:37 PM, Alex Deucher <alexdeucher@...il.com> wrote:
>> On Thu, Sep 13, 2012 at 2:17 PM, Jerome Glisse <j.glisse@...il.com> wrote:
>>> On Thu, Sep 13, 2012 at 10:13 AM, Dmitry Cherkasov
>>> <dcherkassov@...il.com> wrote:
>>>> PDE/PTE update code uses CP ring for memory writes.
>>>> All page table entries are preallocated for now in alloc_pt().
>>>>
>>>> It is made as whole because it's hard to divide it to several patches
>>>> that compile and doesn't break anything being applied separately.
>>>>
>>>> Tested on cayman card.
>>>>
>>>> Signed-off-by: Dmitry Cherkasov <Dmitrii.Cherkasov@....com>
>>>> ---
>>>> I couldn't test in on SI card, so would be happy if someone could check it there.
>>> I wonder how this could have work as you don't set
>>> PAGE_TABLE_BLOCK_SIZE field so each page directory entry cover only 1
>>> page.
>> I think PAGE_TABLE_BLOCK_SIZE refers number of 4k pages used for PTE
>> entries per PDE.  E.g., 1 4k page contains 512 64 bit PTEs. so if
>> BLOCK_SIZE is set to 1 page, each PDE points to 1 page (4k) or PTE
>> entries.  If BLOCK_SIZE is 2, each PDE points to 2 pages (8k) or PTEs,
>> etc.
>>
>> Alex
>>
> If so then it's ok
Yeah, minor nitpick: BLOCK_SIZE seems to be number of 4k pages in a page 
directory entry minus 1.

So with a BLOCK_SIZE of 0 you get one 4K page and with a BLOCK_SIZE of 1 
you get 8K, etc...

Christian.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/