On 6/20/22 16:42, Arnd Bergmann wrote:
On Mon, Jun 20, 2022 at 5:54 PM <guoren@xxxxxxxxxx> wrote:
+config RISCV_USE_QUEUED_SPINLOCKS
+ bool "Using queued spinlock instead of ticket-lock"
Maybe we can just make ARCH_USE_QUEUED_SPINLOCKS
user visible and give users the choice between the two generic
implementations across all architectures that support the qspinlock
variant.
In arch/riscv, you'd then just have a
select ARCH_HAVE_QUEUED_SPINLOCKS
diff --git a/arch/riscv/include/asm/spinlock.h
b/arch/riscv/include/asm/spinlock.h
new file mode 100644
index 000000000000..fd3fd09cff52
--- /dev/null
+++ b/arch/riscv/include/asm/spinlock.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS
+#include <asm/qspinlock.h>
+#include <asm/qrwlock.h>
+#else
+#include <asm-generic/spinlock.h>
+#endif
+
Along the same lines:
I think I'd prefer the header changes to be done in the asm-generic
version of this file, so this can be shared across all architectures
that want to give the choice between ticket and queued spinlock.
I concur. Qspinlock is only needed if we want to support systems with a
large number of CPUs. For systems with a small number of CPUs. It
doesn't matter if qspinlock or the ticket lock is being used.
Cheers,
Longman
