Messages in this thread | | | Date | Wed, 04 Nov 2009 08:12:18 +1100 | From | Nigel Cunningham <> | Subject | Re: [PATCHv2 2/5] vmscan: Kill hibernation specific reclaim logic and unify it |
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Hi Rafael.
Rafael J. Wysocki wrote: > On Monday 02 November 2009, Nigel Cunningham wrote: >> Hi. > > Hi, > >> KOSAKI Motohiro wrote: >>>> I haven't given much thought to numa awareness in hibernate code, but I >>>> can say that the shrink_all_memory interface is woefully inadequate as >>>> far as zone awareness goes. Since lowmem needs to be atomically restored >>>> before we can restore highmem, we really need to be able to ask for a >>>> particular number of pages of a particular zone type to be freed. >>> Honestly, I am not suspend/hibernation expert. Can I ask why caller need to know >>> per-zone number of freed pages information? if hibernation don't need highmem. >>> following incremental patch prevent highmem reclaim perfectly. Is it enough? >> (Disclaimer: I don't think about highmem a lot any more, and might have >> forgotten some of the details, or swsusp's algorithms might have >> changed. Rafael might need to correct some of this...) >> >> Imagine that you have a system with 1000 pages of lowmem and 5000 pages >> of highmem. Of these, 950 lowmem pages are in use and 500 highmem pages >> are in use. >> >> In order to to be able to save an image, we need to be able to do an >> atomic copy of those lowmem pages. >> >> You might think that we could just copy everything into the spare >> highmem pages, but we can't because mapping and unmapping the highmem >> pages as we copy the data will leave us with an inconsistent copy. > > This isn't the case any more for the mainline hibernate code. We use highmem > for storing image data as well as lowmem.
Highmem for storing copies of lowmem pages?
Regards,
Nigel
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