From da9e5c04be589524101aac31746902b6803581e4 Mon Sep 17 00:00:00 2001 From: Can Peng Date: Fri, 19 Sep 2025 18:00:42 +0800 Subject: [PATCH] arm/syscalls: mark syscall invocation as likely in invoke_syscall The invoke_syscall() function is overwhelmingly called for valid system call entries. Annotate the main path with likely() to help the compiler generate better branch prediction hints, reducing CPU pipeline stalls due to mispredictions. This is a micro-optimization targeting syscall-heavy workloads [1]. Link: https://lore.kernel.org/r/20250922121730.986761-1-pengcan@kylinos.cn [1] Signed-off-by: Can Peng Signed-off-by: Will Deacon --- arch/arm64/kernel/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index c442fcec6b9e8..aba7ca6bca2d1 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -43,7 +43,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, add_random_kstack_offset(); - if (scno < sc_nr) { + if (likely(scno < sc_nr)) { syscall_fn_t syscall_fn; syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)]; ret = __invoke_syscall(regs, syscall_fn); -- 2.47.3