riscv: don't probe unaligned access speed if already done

If misaligned_access_speed percpu var isn't so called "HWPROBE MISALIGNED UNKNOWN", it means the probe has happened(this is possible for example, hotplug off then hotplug on one cpu), and the percpu var has been set, don't probe again in this case. Signed-off-by: Jisheng Zhang <[email protected]> Fixes: 584ea65 ("RISC-V: Probe for unaligned access speed") Reviewed-by: Conor Dooley <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Palmer Dabbelt <[email protected]>
kawasaki · Nov 5, 2023 · c20d36c · c20d36c
1 parent 0786387
commit c20d36c
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
@@ -572,6 +572,10 @@ void check_unaligned_access(int cpu)
 	if (check_unaligned_access_emulated(cpu))
 		return;
 
+	/* We are already set since the last check */
+	if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN)
+		return;
+
 	page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE));
 	if (!page) {
 		pr_warn("Can't alloc pages to measure memcpy performance");