Re: [S+Q3 20/23] slub: Shared cache to exploit cross cpu cachingabilities.

From: Christoph Lameter
Date: Wed Aug 18 2010 - 15:32:18 EST


On Tue, 17 Aug 2010, Christoph Lameter wrote:

> > >
> > > > [ 15.752467]
> > > > [ 15.752467] INFO: 0xffff880c7e5f3ec0-0xffff880c7e5f3ec7. First byte 0x30 instead of 0xbb
> > > > [ 15.752467] INFO: Allocated in 0xffff88087e4f11e0 age=131909211166235 cpu=2119111312 pid=-30712
> > > > [ 15.752467] INFO: Freed in 0xffff88087e4f13f0 age=131909211165707 cpu=2119111840 pid=-30712
> > > > [ 15.752467] INFO: Slab 0xffffea002bba4d28 objects=51 new=3 fp=0x0007000000000000 flags=0xa00000000000080
> > > > [ 15.752467] INFO: Object 0xffff880c7e5f3eb0 @offset=3760
> > > > [ 15.752467]
> > > > [ 15.752467] Bytes b4 0xffff880c7e5f3ea0: 18 00 00 00 7e 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ....~...ZZZZZZZZ
> > > > [ 15.752467] Object 0xffff880c7e5f3eb0: d0 0f 4f 7e 08 88 ff ff 80 10 4f 7e 08 88 ff ff .O~....O~..
> > > > [ 15.752467] Redzone 0xffff880c7e5f3ec0: 30 11 4f 7e 08 88 ff ff 0.O~..
> > > > [ 15.752467] Padding 0xffff880c7e5f3ef8: 00 16 4f 7e 08 88 ff ff ..O~..
> > >
> > > 16 bytes allocated and a pointer array much larger than that is used.
> > >
> >
> > Since the problem persists with and without CONFIG_SLUB_DEBUG_ON, I'd
> > speculate that this is a problem with node scalability on my 4-node system
> > if this boots fine for you.
>
> Looking at it. I have a fakenuma setup here that does not trigger it.
> Guess I need something more real.

Cannot reproduce it on my real 2 node numa system either.
Trouble is that results in only one alien cache per cpu caching domain.

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