On Sat, 28 Apr 2007, Rafael J. Wysocki wrote:
We're freezing many of them just fine. ;-)
And can you name a _single_ advantage of doing so?
Yes. We have a lot less interdependencies to worry about during the whole
operation.
It so happens, that most people wouldn't notice or care that kmirrord got
frozen (kernel thread picked at random - it might be one of the threads
that has gotten special-cased to not do that), but I have yet to hear a
single coherent explanation for why it's actually a good idea in the first
place.
Well, I don't know if that's a 'coherent' explanation from your point of view
(probably not), but I'll try nevertheless:
1) if the kernel threads are frozen, we know that they don't hold any locks
that could interfere with the freezing of device drivers,
does teh process of freezing really wait until all locks have been released?
2) if they are frozen, we know, for example, that they won't call user mode
helpers or do similar things,
this won't matter unless the user mode helpers are going to do I/O or other
permanent changes
3) if they are frozen, we know that they won't submit I/O to disks and
potentially damage filesystems (suspend2 has much more problems with that
than swsusp, but still. And yes, there have been bug reports related to it,
so it's not just my fantasy).
if you have the filesystems checkpointed then I/O after the freeze won't matter
as you just revert to the checkpoint (and since this is going to be thrown away
it can stay in ram)
if we are willing to make a break with the past to implement the new snapshot
capability, we should be able to use the LVM snapshot code to handle the
filesystem
David Lang
Probably some other people can say more about it.
And it has added totally idiotic code to every single kernel thread main
loop. For _no_ reason, except that the concept was broken, and needed more
breakage to just make it work.
It is actually useful for some things other than the hibernation/suspend, the
code is not idiotic (it's one line of code in the majority of cases) and you
should take that "I hate everything even remotely related to hibernation" hat
off, really.
Greetings,
Rafael
-
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/
-
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/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
