Messages in this thread | | | Date | Fri, 6 Feb 2009 17:03:54 +0900 | From | MinChan Kim <> | Subject | Re: [PATCH 3/3][RFC] swsusp: shrink file cache first |
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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 ?
> 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 ?
-- Kinds Regards MinChan Kim
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