Questions about mm

Questions about mm

[Sanidhya Kashyap]

Hello everyone,

I have some questions about page allocation and locking.

- Suppose that a process is about to be killed and before that happens, I want
to keep the content of the page intact in the memory, i.e. the page should
neither be zeored or allocated to some other process unless required. In order
to achieve this, what can be the most optimal approach in which the internals of
the kernel is not changed besides adding a syscall or something.

- Another is what happens if I increase the count of mm_users and mm_count
before and later that process gets killed. Assuming that the mm was linked only
to the killed process. What will happen in this case?

- Last question that I wanted to know is what will happen if I change the flags
of the pages to be reserved and unevictable?
Is it possible for the pages to be set pinned as well?
Can this approach help me soling the first issue or I might get a BUG by some
other component in kernel?

Since, I have just started playing with the kernel, so there is a possibility
that I might have asked something very silly/horrific. Please bear with me.

Thanks,
Sanidhya

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Re: Questions about mm

[Chintan Pandya]

Hi Sanidhya,

Could you explain your use-case or debug method ? Why do you need to 
keep a page even after its original process have got killed ?

thanks,

On 12/08/2014 09:54 AM, Sanidhya Kashyap wrote:
> Hello everyone,
>
> I have some questions about page allocation and locking.
>
> - Suppose that a process is about to be killed and before that happens, I want
> to keep the content of the page intact in the memory, i.e. the page should
> neither be zeored or allocated to some other process unless required. In order
> to achieve this, what can be the most optimal approach in which the internals of
> the kernel is not changed besides adding a syscall or something.
>
> - Another is what happens if I increase the count of mm_users and mm_count
> before and later that process gets killed. Assuming that the mm was linked only
> to the killed process. What will happen in this case?
>
> - Last question that I wanted to know is what will happen if I change the flags
> of the pages to be reserved and unevictable?
> Is it possible for the pages to be set pinned as well?
> Can this approach help me soling the first issue or I might get a BUG by some
> other component in kernel?
>
> Since, I have just started playing with the kernel, so there is a possibility
> that I might have asked something very silly/horrific. Please bear with me.
>
> Thanks,
> Sanidhya
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email:<a href=mailto:"dont@kvack.org">  email@kvack.org</a>


-- 
Chintan Pandya

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation

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