[PATCH 2/2] arm64: Allow changing of attributes outside of modules
qiuxishi at huawei.com
Thu Nov 5 03:10:58 PST 2015
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?
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.
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?
> 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?
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