diff mbox

[v3] mm: make expand_downwards symmetrical to expand_upwards

Message ID 1303248103.11237.16.camel@mulgrave.site (mailing list archive)
State Not Applicable
Headers show

Commit Message

James Bottomley April 19, 2011, 9:21 p.m. UTC 
On Tue, 2011-04-19 at 15:56 -0500, Christoph Lameter wrote:
> On Tue, 19 Apr 2011, James Bottomley wrote:
> 
> > > > I told you ... I forced an allocation into the first discontiguous
> > > > region.  That will return 1 for page_to_nid().
> > >
> > > How? The kernel has no concept of a node 1 without CONFIG_NUMA and so you
> > > cannot tell the page allocator to allocate from node 1.
> >
> > Yes, it does, as I explained in the email.
> 
> Looked through it and canot find it. How would that be possible to do
> with core kernel calls since the page allocator calls do not allow you to
> specify a node under !NUMA.

it's used under DISCONTIGMEM to identify the pfn array.

> > Don't be silly: alpha, ia64, m32r, m68k, mips, parisc, tile and even x86
> > all use the discontigmem memory model in some configurations.
> 
> I guess DISCONTIGMEM is typically used together with NUMA. Otherwise we
> would have run into this before.

Which bit of my telling you that six architectures already use it this
way did you not get?  I'm not really interested in reconciling your
theories with how we currently operate.  If you want to require NUMA
with DISCONTIGMEM, fine, we'll just define SLUB as broken if that's not
true ... that will fix my boot panic reports.

James

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Comments

Christoph Lameter (Ampere) April 19, 2011, 9:39 p.m. UTC | #1 
On Tue, 19 Apr 2011, James Bottomley wrote:

> > I guess DISCONTIGMEM is typically used together with NUMA. Otherwise we
> > would have run into this before.
>
> Which bit of my telling you that six architectures already use it this
> way did you not get?  I'm not really interested in reconciling your
> theories with how we currently operate.  If you want to require NUMA
> with DISCONTIGMEM, fine, we'll just define SLUB as broken if that's not
> true ... that will fix my boot panic reports.

Which part of me telling you that you will break lots of other things in
the core kernel dont you get? If you were able to get to a command prompt
with SLAB then lets all be happy for as long as it lasts.


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James Bottomley April 19, 2011, 9:48 p.m. UTC | #2 
On Tue, 2011-04-19 at 16:39 -0500, Christoph Lameter wrote:
> On Tue, 19 Apr 2011, James Bottomley wrote:
> 
> > > I guess DISCONTIGMEM is typically used together with NUMA. Otherwise we
> > > would have run into this before.
> >
> > Which bit of my telling you that six architectures already use it this
> > way did you not get?  I'm not really interested in reconciling your
> > theories with how we currently operate.  If you want to require NUMA
> > with DISCONTIGMEM, fine, we'll just define SLUB as broken if that's not
> > true ... that will fix my boot panic reports.
> 
> Which part of me telling you that you will break lots of other things in
> the core kernel dont you get?

I get that you tell me this ... however, the systems that, according to
you, should be failing to get to boot prompt do, in fact, manage it.

>  If you were able to get to a command prompt
> with SLAB then lets all be happy for as long as it lasts.

We can't re-engineer DISCONTIGMEM as a bug fix, so something like this
has to be done for stable regardless.

James


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diff mbox

Patch

diff --git a/init/Kconfig b/init/Kconfig
index 56240e7..a7ad8fb 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1226,6 +1226,7 @@  config SLAB
 	  per cpu and per node queues.
 
 config SLUB
+	depends on BROKEN || NUMA || !DISCONTIGMEM
 	bool "SLUB (Unqueued Allocator)"
 	help
 	   SLUB is a slab allocator that minimizes cache line usage