Messages in this thread | | | Date | Thu, 21 Nov 2019 07:04:44 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v10 6/6] x86/split_lock: Enable split lock detection by kernel parameter |
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* Fenghua Yu <fenghua.yu@intel.com> wrote:
> Split lock detection is disabled by default. Enable the feature by > kernel parameter "split_lock_detect". > > Usually it is enabled in real time when expensive split lock issues > cannot be tolerated so should be fatal errors, or for debugging and > fixing the split lock issues to improve performance. > > Please note: enabling this feature will cause kernel panic or SIGBUS > to user application when a split lock issue is detected. > > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> > Reviewed-by: Tony Luck <tony.luck@intel.com> > --- > .../admin-guide/kernel-parameters.txt | 10 ++++++ > arch/x86/kernel/cpu/intel.c | 34 +++++++++++++++++++ > 2 files changed, 44 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 8dee8f68fe15..1ed313891f44 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3166,6 +3166,16 @@ > > nosoftlockup [KNL] Disable the soft-lockup detector. > > + split_lock_detect > + [X86] Enable split lock detection > + This is a real time or debugging feature. When enabled > + (and if hardware support is present), atomic > + instructions that access data across cache line > + boundaries will result in an alignment check exception. > + When triggered in applications the kernel will send > + SIGBUS. The kernel will panic for a split lock in > + OS code.
It would be really nice to be able to enable/disable this runtime as well, has this been raised before, and what was the conclusion?
Thanks,
Ingo
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