Re: [PATCH v2 2/2] mm/mmu_gather: send tlb_remove_table_smp_sync IPI only to MM CPUs
From: Dave Hansen <hidden>
Date: 2023-06-21 17:43:45
Also in:
linux-arch, linux-arm-kernel, linux-mm, linux-s390, lkml, sparclinux
On 6/20/23 07:46, Yair Podemsky wrote:
quoted hunk ↗ jump to hunk
-void tlb_remove_table_sync_one(void) +#ifdef CONFIG_ARCH_HAS_CPUMASK_BITS +#define REMOVE_TABLE_IPI_MASK mm_cpumask(mm) +#else +#define REMOVE_TABLE_IPI_MASK cpu_online_mask +#endif /* CONFIG_ARCH_HAS_CPUMASK_BITS */ + +void tlb_remove_table_sync_one(struct mm_struct *mm) { /* * This isn't an RCU grace period and hence the page-tables cannot be@@ -200,7 +206,8 @@ void tlb_remove_table_sync_one(void) * It is however sufficient for software page-table walkers that rely on * IRQ disabling. */ - smp_call_function(tlb_remove_table_smp_sync, NULL, 1); + on_each_cpu_mask(REMOVE_TABLE_IPI_MASK, tlb_remove_table_smp_sync, + NULL, true); }
That "REMOVE_TABLE_IPI_MASK" thing is pretty confusing. It *looks* like a constant. It does *NOT* look at all like it consumes 'mm'. Worst case, just create a local variable: if (IS_ENABLED(CONFIG_ARCH_HAS_CPUMASK_BITS)) ipi_mask = mm_cpumask(mm); else ipi_mask = cpu_online_mask; on_each_cpu_mask(ipi_mask, ...); That's a billion times more clear and it'll compile down to the same thing. I do think the CONFIG_ARCH_HAS_CPUMASK_BITS naming is also pretty confusing, but I don't have any better suggestions. Maybe something with "MM_CPUMASK" in it?