Re: [RFC][PATCH] sched: Use lightweight hazard pointers to grab lazy mms
From: Peter Zijlstra <peterz@infradead.org>
Date: 2021-06-17 09:11:09
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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:
quoted hunk ↗ jump to hunk
--- 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 */
quoted hunk ↗ jump to hunk
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?