diff options
author | Anton Blanchard <anton@samba.org> | 2015-04-09 12:52:56 +1000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2015-04-11 20:49:27 +1000 |
commit | c54b2bf1b5e99760d53ea0376e96a046f93df6ae (patch) | |
tree | d81302ccfeed24918d147f0b5b8ddd5dbcab1873 /arch/powerpc/include/asm/nmi.h | |
parent | af9feebe60add19fdd15adee80ac5b4eeb2a489b (diff) |
powerpc: Add ppc64 hard lockup detector support
The hard lockup detector uses a PMU event as a periodic NMI to
detect if we are stuck (where stuck means no timer interrupts have
occurred).
Ben's rework of the ppc64 soft disable code has made ppc64 PMU
exceptions a partial NMI. They can get disabled if an external
interrupt comes in, but otherwise PMU interrupts will fire in
interrupt disabled regions.
We disable the hard lockup detector by default for a few reasons:
- It breaks userspace event based branches on POWER8.
- It is likely to produce false positives on KVM guests.
- Since PMCs can only count to 2^31, counting cycles means we might
take multiple PMU exceptions per second per hardware thread even
if our hard lockup timeout is 10 seconds.
It can be enabled via a boot option, or via procfs.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/nmi.h')
-rw-r--r-- | arch/powerpc/include/asm/nmi.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/nmi.h b/arch/powerpc/include/asm/nmi.h new file mode 100644 index 000000000000..ff1ccb375e60 --- /dev/null +++ b/arch/powerpc/include/asm/nmi.h @@ -0,0 +1,4 @@ +#ifndef _ASM_NMI_H +#define _ASM_NMI_H + +#endif /* _ASM_NMI_H */ |