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powerpc: Add a (CPU/runtime features) flags set to pcpu struct
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Authored by jhibbits on Tue, May 19, 12:48 AM.


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The point of this addition is to cache CPU behavior 'features', to avoid
having to recompute based on CPU, etc.

The first such use case is to avoid the unnecessary manipulation of the
SLBs (Segment Lookaside Buffers) when using the Radix pmap on POWER9.
Since we already get the PCPU pointer wherever we swap the SLB entries,
we can use a cached flag to check if it's necessary to perform the
operation anyway, and skip it when not.

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Build Status
Buildable 31188
Build 28847: arc lint + arc unit

Event Timeline

jhibbits requested review of this revision.Tue, May 19, 12:48 AM
jhibbits created this revision.
jhibbits updated this revision to Diff 72009.Wed, May 20, 2:29 AM

Copy the pc_flags before unleashing the CPUs, instead of recomputing on each CPU.