On Sat, 2010-06-05 at 03:36 +0300, Maxim Levitsky wrote: > On Sat, 2010-06-05 at 09:58 +1000, Nigel Cunningham wrote: > > Hi Maxim. > > > > On 05/06/10 09:39, Maxim Levitsky wrote: > > > On Thu, 2010-06-03 at 16:50 +0200, Pavel Machek wrote: > > >> > > >> "Nigel Cunningham"<ncunningham@xxxxxxxxxxx> wrote: > > >> > > >>> Hi. > > >>> > > >>> On 30/05/10 15:25, Pavel Machek wrote: > > >>>> Hi! > > >>>> > > >>>>> 2. Prior to writing any of the image, also set up new 4k page tables > > >>>>> such that an attempt to make a change to any of the pages we're about to > > >>>>> write to disk will result in a page fault, giving us an opportunity to > > >>>>> flag the page as needing an atomic copy later. Once this is done, write > > >>>>> protection for the page can be disabled and the write that caused the > > >>>>> fault allowed to proceed. > > >>>> > > >>>> Tricky. > > >>>> > > >>>> page faulting code touches memory, too... > > >>> > > >>> Yeah. I realise we'd need to make the pages that are used to record the > > >>> faults be unprotected themselves. I'm imagining a bitmap for that. > > >>> > > >>> Do you see any reason that it could be inherently impossible? That's > > >>> what I really want to know before (potentially) wasting time trying it. > > >> > > >> I'm not sure it is impossible, but it certainly seems way too complex to be > > >> practical. > > >> > > >> 2mb pages will probably present a problem, as will bat mappings on powerpc. > > > > > > > > > Some time ago, after tuxonce caused medium fs corruption twice on my > > > root filesystem (superblock gone for example), I was thinking too about > > > how to make it safe to save whole memory. > > > > I'd be asking why you got the corruption. On the odd occasion where it > > has been reported, it's usually been because the person didn't set up > > their initramfs correctly (resumed after mounting filesystems). Is there > > any chance that you did that? I didn't use any initramfs. I did use kernel modesetting and nouveau. I used ext4. The corruption happened after normal suspend. I replaces swsusp with tuxonice. Anyway, some more or less verified method must be used to save memory because fs corruption is too scary thing to have. I can't say it scared me that much 'cause I had dealt with worse corruptions before, but being thrown to "grub rescue>" on boot is not pleasant thing to see. Best regards, Maxim Levitsky _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
