Messages in this thread | | | Date | Fri, 3 Feb 2006 14:16:02 +0100 | From | Pavel Machek <> | Subject | Re: [ 01/10] [Suspend2] kernel/power/modules.h |
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On Pá 03-02-06 10:20:42, Nigel Cunningham wrote: > Hi. > > On Friday 03 February 2006 08:10, Rafael J. Wysocki wrote: > > On machines with less RAM suspend2 will probably be better > > preformance-wise, and that may be more important than the flexibility. > > Ok. So I bit the bullet and downloaded -mm4 to take a look at this interface > you're making, and I have a few questions:
Great, thanks.
> - It seems to be hardwired to use swap, but you talk about writing to a > network image above. In Suspend2, I just bmap whatever the storage is, and > then submit bios to read and write the data. Is anything like that possible > with this interface? (Could it be extended if not?)
No, it is not hardwired. There's special swap support, but you do not need to use it.
> - Is there any way you could support doing a full image of memory with this > approach? Would you take patches?
Doing full image is certainly possible; it is not important if kernel does the writing or userspace does it. Taking patches definitely depends how they'd look like...
> - Does the data have to be transferred to userspace? Security and efficiency > wise, it would seem to make a lot more sense just to be telling the kernel > where to write things and let it do bio calls like I'm doing at the > moment.
As far as I can see, transfering data to userspace and back does not really cost much:
pavel@amd:~$ time head -c $[1024*1024*1024] < /dev/zero > /dev/null 0.16user 0.27system 0.43 (0m0.439s) elapsed 100.00%CPU
...2000MB/sec is the limit (thinkpad x32). Pavel -- Thanks, Sharp! - 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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