[linux-pm] [PATCH 3/7] PCI PM: Fix saving of device state in pci_legacy_suspend
Benjamin Herrenschmidt
benh at kernel.crashing.org
Wed Feb 4 17:29:23 PST 2009
> > Yup, missed that change in the patch. In fact, I even missed the
> > existence of a WARN_ONCE that takes those text arguments... baaaah. I
> > suppose I should try to read more of lkml :-)
>
> But don't expect to see them on powerpc, they never make it to the
> console.
Allright, that's the problem with our implementation of WARN using a
conditional trap, we don't carry all the variable arguments for the
printf over.
I'm tempted to turn our implementation back to normal C code with an if
and a branch out of line, but Michael seems to say that even with
appropriate use of unlikely() etc... gcc decides to generate the worst
possible code every single time ...
<rant>
such as always inlining the whole printf mumbo jumbo and having the
not-warning case branch over it, not -all- CPUs have good branch
prediction dude, so the icache is going to scream but gcc folks know
better of course....
</rant>
Anyway, I'll see Michael what exactly the situation is here and if we
can fix it a way or another.
Ben.
More information about the linux-pm
mailing list