On Wed, 2023-06-21 at 10:42 -0700, Dave Hansen wrote:

On 6/20/23 07:46, Yair Podemsky wrote:

quoted

-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?

Hi Dave,
Thanks for your suggestions!
I will send a new version with the local variable as you suggested
soon.
As for the config name, what about CONFIG_ARCH_HAS_MM_CPUMASK?
Thanks,
Yair