[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
re: CVS commit: src/sys/arch/sparc/sparc
moved to port-sparc, from source-changes-d:
> > > Module Name: src
> > > Committed By: chs
> > > Date: Sun Nov 4 00:32:47 UTC 2012
> > >
> > > Modified Files:
> > > src/sys/arch/sparc/sparc: locore.s pmap.c
> > >
> > > Log Message:
> > > in cpu_switchto(), remove the MP-unsafe code to mark a pmap active on a
> > > CPU,
> > > pmap_activate() already does this. add MP locking to pmap_activate()
> > > and pmap_deactivate(). move flushing of user windows and virtual caches
> > > from pamp_activate() to pmap_deactivate().
> > hmm. this makes pmap_deactivate() do things in UP that weren't being
> > done before at all. switching to/from kernel/lwp for the same lwp will
> > now be flushing the ctx every time. that seems suboptimal?
> do you just mean that I should have left the #ifdef MULTIPROCESSOR
> around the sp_tlb_flush()? or something more than that?
i'm not sure exactly. i had a quick look at editing it back again
but i didn't like the result. i'm imaging a system that only flushes
the previous context in pmap_activate() if it was not the same. ie,
pmap_deactivate() shouldn't always flush. i don't think this should
be MULTIPROCESSOR-related either.
> > we should really update PMAP_LOCK() to not be kernel lock.
> beyond that, there's still plenty of room for improvement on most platforms.
> I think the best example in our tree at this point is the x86 scheme
> of deferring the MMU-switch work to points where we're actually about to
> reference user mappings, eg. returning to user mode, copyin/copyout, etc.
many pmaps can have simpler locking now, since the rmind-uvmplock
branch was merged. i have a started reducing the use of
sparc64/pmap.c:pmap_lock though there is plenty more to go.
Main Index |
Thread Index |