On Feb 19, 2008 7:11 AM, Ingo Molnar <[EMAIL PROTECTED]> wrote:
> * Torsten Kaiser <[EMAIL PROTECTED]> wrote:
> > On Feb 15, 2008 10:23 PM, Linus Torvalds <[EMAIL PROTECTED]> wrote:
> > >
> > > Ok,
> > > this kernel is a winner.
> >
> > Sadly not for me:
> > [ 5282.056415] ------------[ cut here ]------------
> > [ 5282.059757] kernel BUG at lib/list_debug.c:33!
> > [ 5282.062055] invalid opcode: 0000 [1] SMP
> > [ 5282.062055] CPU 3
>
> hm. Your crashes do seem to span multiple subsystems, but it always
> seems to be around the SLUB code. Could you try the patch below? The
> SLUB code has a new optimization and i'm not 100% sure about it. [the
> hack below switches the SLUB optimization off by disabling the CPU
> feature it relies on.]
>
> Ingo
>
> ------------->
> arch/x86/Kconfig | 4 ----
> 1 file changed, 4 deletions(-)
>
> Index: linux/arch/x86/Kconfig
> ===================================================================
> --- linux.orig/arch/x86/Kconfig
> +++ linux/arch/x86/Kconfig
> @@ -59,10 +59,6 @@ config HAVE_LATENCYTOP_SUPPORT
> config SEMAPHORE_SLEEPERS
> def_bool y
>
> -config FAST_CMPXCHG_LOCAL
> - bool
> - default y
> -
> config MMU
> def_bool y
>
$ grep FAST_CMPXCHG_LOCAL */.config
linux-2.6.24-rc2-mm1/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.24-rc3-mm1/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.24-rc3-mm2/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.24-rc6-mm1/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.24-rc8-mm1/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.25-rc1/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.25-rc2-mm1/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
linux-2.6.25-rc2/.config:CONFIG_FAST_CMPXCHG_LOCAL=y
-rc2-mm1 still worked for me.
Did you mean the new SLUB_FASTPATH?
$ grep "define SLUB_FASTPATH" */mm/slub.c
linux-2.6.25-rc1/mm/slub.c:#define SLUB_FASTPATH
linux-2.6.25-rc2-mm1/mm/slub.c:#define SLUB_FASTPATH
linux-2.6.25-rc2/mm/slub.c:#define SLUB_FASTPATH
The 2.6.24-rc3+ mm-kernels did crash for me, but don't seem to contain this...
On the other hand:
>From the crash in 2.6.25-rc2-mm1:
[59987.116182] RIP [<ffffffff8029f83d>] kmem_cache_alloc_node+0x6d/0xa0
(gdb) list *0xffffffff8029f83d
0xffffffff8029f83d is in kmem_cache_alloc_node (mm/slub.c:1646).
1641 if (unlikely(is_end(object) || !node_match(c, node))) {
1642 object = __slab_alloc(s, gfpflags,
node, addr, c);
1643 break;
1644 }
1645 stat(c, ALLOC_FASTPATH);
1646 } while (cmpxchg_local(&c->freelist, object, object[c->offset])
1647
!= object);
1648 #else
1649 unsigned long flags;
1650
That code is part for SLUB_FASTPATH.
I'm willing to test the patch, but don't know how fast I can find the
time to do it, so my answer if your patch helps might be delayed until
the weekend.
Torsten
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