On Fri, 11 May 2007, Andrew Morton wrote:
> On Fri, 11 May 2007 10:29:30 +0200 Andi Kleen <[email protected]> wrote:
>
> > > I'm guessing (haven't rechecked source) that the cpu_idle() call comes
> > > about because the top level pgd of a process gets freed very late in
> > > its exit, and after a great flurry of processes have just exited,
> > > perhaps there was nothing to free up the accumulation. Though
> > > it still strikes me as an odd place to do it.
> >
> > I always found it odd and probably the wrong place too.
>
> so... what's the bottom line here, guys? Should we change that patch?
The bottom line... I can see why you're asking for that ;)
I'd say delete the change to arch/i386/kernel/smp.c - contrary to
what Christoph says, no other arch buries a check_pgt_cache() call
in flush_tlb_mm(), that just seems to be a thinko: i386 has the usual
call to it from tlb_finish_mmu() - _that_ is the one which he and
David were talking about.
I'm just worried that there might somewhere be a call to flush_tlb_mm()
which would now be surprised to be freeing pages: almost certainly not,
but why raise that concern? It's just not flush_tlb_mm()'s business.
The cpu_idle() call should stay for now: we're agreed that it's odd,
but there's plenty of precedent for it, and it's easier to imagine it
serves a real purpose, and shouldn't be removed without replacement.
Bill raised a real concern about unnecessary PAE pgd memory usage,
but let's get the patch into -rc1 to enable the wider SLUB testing,
before coming back to fix that up. His micro-optimizations can wait.
IMHO
Hugh
-
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]
