From: qiuxishi@huawei•com (Xishi Qiu)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/2] arm64: Allow changing of attributes outside of modules
Date: Thu, 5 Nov 2015 19:10:58 +0800 [thread overview]
Message-ID: <563B3942.90305@huawei.com> (raw)
In-Reply-To: <563A4A74.60900@redhat.com>
On 2015/11/5 2:12, Laura Abbott wrote:
> On 11/03/2015 06:59 PM, zhong jiang wrote:
>>
>> Hi Laura
>>
>> This patch seems vaild, but I didn't feel very reasonable.
>> Because of the large page to make TLB performance better, just
>> split it if it is necessary.therefore, I think the first thing
>> we try to keep it, if they fail ,and then to split.
>>
>
> I'm not quite sure I understand the request. We know we are going
> to have to have something mapped at page size granularity so we
> are going to have to break down the larger mappings no matter
> what. Can you explain a bit more where you think we could try to
> keep the larger mappings?
>
Hi Laura,
He means like this, if the range is aligned with large page, we
need not to split it, just change the flag.
I have one more question.
alloc_init_pud()
...
if (!pud_none(old_pud))
...
memblock_free(table, PAGE_SIZE);
...
Here we will free the memory from pmd page, so why not free
more memory from 512 pte pages, if the 512 old pmds are not none?
Thanks,
Xishi Qiu
> At least two things I noticed looking at this again though:
> - This only splits the start address. If the range happens
> to overlap a pud/pmd this won't work. I'll address that in v2
> - We're always flushing the TLB even if nothing changed. Was
> this what you were referring to?
>
>
>> thanks
>> zhongjiang
>>
>>
>
> Thanks,
> Laura
>
>
> .
>
next prev parent reply other threads:[~2015-11-05 11:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-03 21:48 [PATCH 0/2] Support for set_memory_* outside of module space Laura Abbott
2015-11-03 21:48 ` [PATCH 1/2] arm64: Get existing page protections in split_pmd Laura Abbott
2015-11-05 7:07 ` Ard Biesheuvel
2015-11-05 10:15 ` Xishi Qiu
2015-11-06 1:24 ` Laura Abbott
2015-11-03 21:48 ` [PATCH 2/2] arm64: Allow changing of attributes outside of modules Laura Abbott
2015-11-04 3:17 ` zhong jiang
2015-11-05 7:44 ` Ard Biesheuvel
2015-11-06 1:35 ` Laura Abbott
[not found] ` <563974A8.3060306@huawei.com>
[not found] ` <563A4A74.60900@redhat.com>
2015-11-05 11:10 ` Xishi Qiu [this message]
2015-11-06 1:11 ` Laura Abbott
2015-11-05 11:29 ` Xishi Qiu
2015-11-03 23:42 ` [PATCH 0/2] Support for set_memory_* outside of module space Kees Cook
2015-11-04 18:51 ` Laura Abbott
2015-11-04 19:06 ` Kees Cook
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