On 6/10/19 4:26 PM, Matt Fleming wrote: > On Wed, 05 Jun, at 08:00:35PM, Peter Zijlstra wrote: >> >> And then we had two magic values :/ >> >> Should we not 'fix' RECLAIM_DISTANCE for EPYC or something? Because >> surely, if we want to load-balance agressively over 30, then so too >> should we do node_reclaim() I'm thikning. > > Yeah we can fix it just for EPYC, Mel suggested that approach originally. > > Suravee, Tom, what's the best way to detect these EPYC machines that need to > override RECLAIM_DISTANCE?
You should be able to do it based on the family. There's an init_amd_zn() function in arch/x86/kernel/cpu/amd.c. You can add something there or, since init_amd_zn() sets X86_FEATURE_ZEN, you could check for that if you prefer putting it in a different location. Thanks, Tom >
