Re: [PATCH 0/3] ARM 4Kstacks: introduction

[Måns Rullgård]

Ming Lei <tom.leiming@xxxxxxxxx> writes:

> On Wed, Oct 19, 2011 at 6:51 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>> On Tuesday 18 October 2011 17:26:44 Tim Bird wrote:
>>> Even inside Sony, usage of 4K stacks is limited
>>> to some very special cases, where memory is exceedingly
>>> tight (we have one system with 4M of RAM).  And we
>>> don't mind lopping off features or coding around
>>> problem areas to support our special case.
>>
>> I would imagine that in those cases, you can gain more by reducing the
>> number of threads in the system. What is the highest number of
>> concurrent threads that you expect in a limited use case with no
>> networking or block devices?
>
> If system run for some time, sometimes it may be difficult for
> memory allocator to allocate 2 continuous page frames even  there are
> many spare page frames in system because of
> fragment issue, so the patch does make sense. Anyway,
> it provides one option for user to apply 4k stack to avoid
> such kind of process creation failure.

Can't page migration be used in these situations?

-- 
Måns Rullgård
mans@xxxxxxxxx
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