Messages in this thread | | | Date | Thu, 25 Apr 2019 12:58:32 +0200 (CEST) | From | Thomas Gleixner <> | Subject | RE: [PATCH v8 13/15] x86/split_lock: Enable split lock detection by default |
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On Thu, 25 Apr 2019, David Laight wrote:
> From: Fenghua Yu > > Sent: 24 April 2019 20:33 > > A split locked access locks bus and degrades overall memory access > > performance. When split lock detection feature is enumerated, enable > > the feature by default by writing 1 to bit 29 in MSR TEST_CTL to find > > any split lock issue. > > You can't enable this by default until ALL the known potentially > misaligned locked memory operations have been fixed.
Errm? The result will be a WARN_ON() printed and no further damage. It's not making anything worse than it is now. In fact we just should add a
WARN_ON_ONCE(!aligned_to_long(p)) to all the xxx_bit() operations.
so we catch them even when they do not trigger that #AC thingy.
Thanks,
tglx
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