Re: [PATCH] mm: Add new vma flag VM_LOCAL_CPU

From: Boaz Harrosh
Date: Tue May 15 2018 - 13:39:51 EST


On 15/05/18 17:17, Peter Zijlstra wrote:
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>>
>> So I would love some mm guy to explain where are those bits collected?
>
> Depends on the architecture, some architectures only ever set bits,
> some, like x86, clear bits again. You want to look at switch_mm().
>
> Basically x86 clears the bit again when we switch away from the mm and
> have/will invalidate TLBs for it in doing so.
>

Ha, OK I am starting to get a picture.

>> Which brings me to another question. How can I find from
>> within a thread Say at the file_operations->mmap() call that the thread
>> is indeed core-pinned. What mm_cpumask should I inspect?
>
> is_percpu_thread().

Right thank you a lot Peter. this helps.

Boaz
> .
>