Hi! > > > Some time ago we discussed the possibility of simplifying the swsusp's > > > approach > > > towards tracking the swap pages allocated by it for saving the image (so > > > that > > > they can be freed if there's an error). > > > > > > I think we can get back to it now, as it is a nice optimization that > > > should > > > allow us to use less memory (almost always) and improve performance a bit. > > > > > > > Well, I do not think you can measure the difference, but... > > As far as the memory usage is concerned, I can. :-) Usually, it takes 1 > extent > (40 B on x86_64) to register all of the allocated swap pages. If bitmaps are > used, we need as many bits as there are swap pages available (for 1 GB swap > and 4 KB pages that would be ~250000 bits, which gives ~8 pages, and we can > save more than 800 extents using that much memory).
Well... obviously it works for the best case. OTOH, for the worst, it needs 40bytes for every 2 bits. That's 16000% worse. And for that nightmare-fragmented 1GB swap, you'll need 5000000bytes... which is pretty bad. OTOH 5MB RAM per 1GB swap is not _too_ bad... so we can do it... > > > kernel/power/power.h | 27 +--------- > > > kernel/power/swap.c | 18 +----- > > > kernel/power/swsusp.c | 135 > > > ++++++++++++++++++++++++++------------------------ > > > kernel/power/user.c | 22 +------- > > > 4 files changed, 85 insertions(+), 117 deletions(-) ...and call it 'cleanup' not 'speedup'. > > ....as it removes code... I think we can do that. But it is 2.6.23+ > > material. > > Yes, I think so, but still we can ask Andrew to include it into -mm earlier? > ;-) Yes, that's okay with me. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
