On Fri, Jul 21, 2023 at 03:57:16PM +0800, thunder.leizhen@xxxxxxxxxxxxxxx wrote:
> From: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
>
> The code and comments of self detected and other detected are the same
> except the output function. Combine the same parts to avoid duplication.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
This looks like a nice simplification, thank you!
Please make this not depend on the earlier patch and resend.
Thanx, Paul
> ---
> kernel/rcu/tree_stall.h | 36 +++++++++++-------------------------
> 1 file changed, 11 insertions(+), 25 deletions(-)
>
> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
> index 371713f3f7d15d9..0ade7f9dcaa18da 100644
> --- a/kernel/rcu/tree_stall.h
> +++ b/kernel/rcu/tree_stall.h
> @@ -711,7 +711,7 @@ static void print_cpu_stall(unsigned long gps)
>
> static void check_cpu_stall(struct rcu_data *rdp)
> {
> - bool didstall = false;
> + bool self_detected;
> unsigned long gs1;
> unsigned long gs2;
> unsigned long gps;
> @@ -758,10 +758,10 @@ static void check_cpu_stall(struct rcu_data *rdp)
> return; /* No stall or GP completed since entering function. */
> rnp = rdp->mynode;
> jn = jiffies + ULONG_MAX / 2;
> + self_detected = READ_ONCE(rnp->qsmask) & rdp->grpmask;
> if (rcu_gp_in_progress() &&
> - (READ_ONCE(rnp->qsmask) & rdp->grpmask) &&
> + (self_detected || ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) &&
> cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) {
> -
> /*
> * If a virtual machine is stopped by the host it can look to
> * the watchdog like an RCU stall. Check to see if the host
> @@ -770,31 +770,17 @@ static void check_cpu_stall(struct rcu_data *rdp)
> if (kvm_check_and_clear_guest_paused())
> return;
>
> - /* We haven't checked in, so go dump stack. */
> - print_cpu_stall(gps);
> - if (READ_ONCE(rcu_cpu_stall_ftrace_dump))
> - rcu_ftrace_dump(DUMP_ALL);
> - didstall = true;
> -
> - } else if (rcu_gp_in_progress() &&
> - ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY) &&
> - cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) {
> -
> - /*
> - * If a virtual machine is stopped by the host it can look to
> - * the watchdog like an RCU stall. Check to see if the host
> - * stopped the vm.
> - */
> - if (kvm_check_and_clear_guest_paused())
> - return;
> + if (self_detected) {
> + /* We haven't checked in, so go dump stack. */
> + print_cpu_stall(gps);
> + } else {
> + /* They had a few time units to dump stack, so complain. */
> + print_other_cpu_stall(gs2, gps);
> + }
>
> - /* They had a few time units to dump stack, so complain. */
> - print_other_cpu_stall(gs2, gps);
> if (READ_ONCE(rcu_cpu_stall_ftrace_dump))
> rcu_ftrace_dump(DUMP_ALL);
> - didstall = true;
> - }
> - if (didstall) {
> +
> jn = jiffies + 3 * rcu_jiffies_till_stall_check() + 3;
> WRITE_ONCE(rcu_state.jiffies_stall, jn);
> }
> --
> 2.25.1
>
