From c20d36cc2a2073d4cdcda92bd7a1bb9b3b3b7c79 Mon Sep 17 00:00:00 2001 From: Jisheng Zhang Date: Tue, 12 Sep 2023 23:40:40 +0800 Subject: [PATCH] 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 Fixes: 584ea6564bca ("RISC-V: Probe for unaligned access speed") Reviewed-by: Conor Dooley Link: https://lore.kernel.org/r/20230912154040.3306-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/cpufeature.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 970a71422beea8..6a01ded615cdb7 100644 --- 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");