Messages in this thread | | | Date | Thu, 17 Jun 2021 11:10:25 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH] sched: Use lightweight hazard pointers to grab lazy mms |
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On Thu, Jun 17, 2021 at 11:08:03AM +0200, Peter Zijlstra wrote: > On Wed, Jun 16, 2021 at 10:32:15PM -0700, Andy Lutomirski wrote:
> --- a/arch/x86/include/asm/mmu.h > +++ b/arch/x86/include/asm/mmu.h > @@ -66,4 +66,9 @@ typedef struct { > void leave_mm(int cpu); > #define leave_mm leave_mm > > +/* On x86, mm_cpumask(mm) contains all CPUs that might be lazily using mm */ > +#define for_each_possible_lazymm_cpu(cpu, mm) \ > + for_each_cpu((cpu), mm_cpumask((mm))) > + > + > #endif /* _ASM_X86_MMU_H */
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 8ac693d542f6..e102ec53c2f6 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -19,6 +19,7 @@ >
> + > +#ifndef for_each_possible_lazymm_cpu > +#define for_each_possible_lazymm_cpu(cpu, mm) for_each_online_cpu((cpu)) > +#endif > +
Why can't the x86 implementation be the default? IIRC the problem with mm_cpumask() is that (some) architectures don't clear bits, but IIRC they all should be setting bits, or were there archs that didn't even do that?
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