Re: [PATCH 3/3][RFC] swsusp: shrink file cache first

[MinChan Kim]

On Fri, Feb 6, 2009 at 5:03 PM, MinChan Kim <minchan.kim@xxxxxxxxx> wrote:
> Hi, Johannes.
> I have some questions.
> Just out of curiosity. :)
>
> On Fri, Feb 06, 2009 at 04:11:28AM +0100, Johannes Weiner wrote:
>> File cache pages are saved to disk either through normal writeback by
>> reclaim or by including them in the suspend image written to a
>> swapfile.
>>
>> Writing them either way should take the same amount of time but doing
>> normal writeback and unmap changes the fault behaviour on resume from
>> prefault to on-demand paging, smoothening out resume and giving
>
> What do you mean "unmap"?
> Why normal writeback and unmap chnages the fault behavior on resume ?

Please, Ignore poor first my question. :(
I agree with your opinion.

>> previously cached pages the chance to stay out of memory completely if
>> they are not used anymore.
>>
>> Another reason for preferring file page eviction is that the locality
>> principle is visible in fault patterns and swap might perform really
>> bad with subsequent faulting of contiguously mapped pages.
>
> Why do you think that swap might perform bad with subsequent faulting
> of contiguusly mapped page ?
> You mean normal file system is faster than swap due to readahead and
> smart block of allocation ?

But, I still can't understand this issue.
what mean "page eviction" ? Is it reclaim or swap out ?

>
> --
> Kinds Regards
> MinChan Kim
>
>



-- 
Kinds regards,
MinChan Kim
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