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Hi, On Monday, 26 of September 2005 12:33, Pavel Machek wrote: > Hi! > > > There's a silent assumption in swsusp that always > > sizeof(struct swsusp_info) <= PAGE_SIZE, which is wrong, because > > eg. on x86-64 sizeof(swp_entry_t) = 8. This causes swsusp to skip some pagedir > > pages while reading the image if there are too many of them (depending on the > > architecture, approx. 500 on x86-64). > > Last time I did the math, swsusp_info could cover a *lot* of > memory. It was wrong not to check for overflow, but I do not think we > want to introduce *yet another* linklist. Yes, I thought of another solution, but any of them would require more than one swap page and I'd have to track the swap offsets of them somehow. > Lets see... > > for i386, we have 768 pagedir entries. Each pagedir entry points to > page with 1023 pointers to pages. That means that up-to 768*1023*4096 > bytes image can be saved to swap ~= 768 * 1K * 4K ~= 3 GB. That's more > than enough for i386. > > for x86-64, we can have 128 pagedir entries (could not we fit more > there? 384 entries should fit, no?). Yes. To be exact, 460. > Each pagedir entry has 511 pointers to pages (IIRC)... 512, I think. > that is up-to 128*511*4K ~= 64*1K*4K = 256 MB image. > Hmm, that should still be enough for any 512MB machine, and > probably okay for much bigger machines, too... > > We can still get to 768 MB image (good enough for any 1.5GB machine, > and probably for anything else, too). > > If that is not good enough for you, can you simply allocate more than > 1 page for swsusp_info? No need for linklists yet. I can. The problem is I have to track the swap offsets of these pages which is necessary for resume. Is it guaranteed that the swap offsets of pages allocated in a row will be consecutive? > Andrew, please drop this one. It is too complex solution for quite a > simple problem. Perhaps it is. Anyway the problem hit me when I was playing with swsusp on a machine with 768 MB of RAM. Greetings, Rafael - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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