Messages in this thread | | | Date | Tue, 19 Feb 2008 20:27:47 +0100 | From | "Torsten Kaiser" <> | Subject | Re: Linux 2.6.25-rc2 |
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On Feb 19, 2008 5:20 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > So: > - it might be something else entirely > - it might still be the local cmpxchg, just Torsten didn't happen to > notice it until later.
My new hackbench-testcase also killed 2.6.24-rc2-mm1, so I really noticed to late.
> - it might still be the local cmpxchg, but something else changed its > patterns to actually make it start triggering. > > and in general I don't think we should revert it unless we have stronger > indications that it really is the problem (eg somebody finds the actual > bug, or a reporter can confirm that it goes away when the local cmpxchg > optimization is disabled).
I tried the following three patches:
switching the barrier() for a smp_mb() in 2.6.25-rc2-mm1: -> crashed
reverting the FASTPATH-patch in 2.6.25-rc2: -> worked
only removed FAST_CMPXCHG_LOCAL from arch/x86/Kconfig -> worked
So all of these tests seem to confirm, that the bug is in the new SLUB fastpath.
Torsten
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