diff mbox series

[RFC,60/86] treewide: torture: remove cond_resched()

Message ID 20231107230822.371443-4-ankur.a.arora@oracle.com (mailing list archive)
State New
Headers show
Series Make the kernel preemptible | expand

Commit Message

Ankur Arora Nov. 7, 2023, 11:07 p.m. UTC 
Some cases changed to cond_resched_stall() to avoid changing
the behaviour of the test too drastically.

Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
 kernel/rcu/rcuscale.c   | 2 --
 kernel/rcu/rcutorture.c | 8 ++++----
 kernel/scftorture.c     | 1 -
 kernel/torture.c        | 1 -
 4 files changed, 4 insertions(+), 8 deletions(-)

Comments

Paul E. McKenney Nov. 21, 2023, 1:02 a.m. UTC | #1 
On Tue, Nov 07, 2023 at 03:07:56PM -0800, Ankur Arora wrote:
> Some cases changed to cond_resched_stall() to avoid changing
> the behaviour of the test too drastically.
> 
> Cc: Davidlohr Bueso <dave@stgolabs.net>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Frederic Weisbecker <frederic@kernel.org>
> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>

Given lazy preemption, I am OK with dropping the cond_resched()
invocations from the various torture tests.

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>

> ---
>  kernel/rcu/rcuscale.c   | 2 --
>  kernel/rcu/rcutorture.c | 8 ++++----
>  kernel/scftorture.c     | 1 -
>  kernel/torture.c        | 1 -
>  4 files changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
> index ffdb30495e3c..737620bbec83 100644
> --- a/kernel/rcu/rcuscale.c
> +++ b/kernel/rcu/rcuscale.c
> @@ -672,8 +672,6 @@ kfree_scale_thread(void *arg)
>  			else
>  				kfree_rcu(alloc_ptr, rh);
>  		}
> -
> -		cond_resched();
>  	} while (!torture_must_stop() && ++loop < kfree_loops);
>  
>  	if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index ade42d6a9d9b..158d58710b51 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -81,7 +81,7 @@ torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
>  torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
>  torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
>  torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
> -torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
> +torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched_stall() behind need_resched()");
>  torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
>  torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
>  torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
> @@ -2611,7 +2611,7 @@ static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
>  		return;
>  	}
>  	// No userspace emulation: CB invocation throttles call_rcu()
> -	cond_resched();
> +	cond_resched_stall();
>  }
>  
>  /*
> @@ -2691,7 +2691,7 @@ static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
>  		udelay(10);
>  		cur_ops->readunlock(idx);
>  		if (!fwd_progress_need_resched || need_resched())
> -			cond_resched();
> +			cond_resched_stall();
>  	}
>  	(*tested_tries)++;
>  	if (!time_before(jiffies, stopat) &&
> @@ -3232,7 +3232,7 @@ static int rcu_torture_read_exit(void *unused)
>  				errexit = true;
>  				break;
>  			}
> -			cond_resched();
> +			cond_resched_stall();
>  			kthread_stop(tsp);
>  			n_read_exits++;
>  		}
> diff --git a/kernel/scftorture.c b/kernel/scftorture.c
> index 59032aaccd18..24192fe01125 100644
> --- a/kernel/scftorture.c
> +++ b/kernel/scftorture.c
> @@ -487,7 +487,6 @@ static int scftorture_invoker(void *arg)
>  			set_cpus_allowed_ptr(current, cpumask_of(cpu));
>  			was_offline = false;
>  		}
> -		cond_resched();
>  		stutter_wait("scftorture_invoker");
>  	} while (!torture_must_stop());
>  
> diff --git a/kernel/torture.c b/kernel/torture.c
> index b28b05bbef02..0c0224c76275 100644
> --- a/kernel/torture.c
> +++ b/kernel/torture.c
> @@ -747,7 +747,6 @@ bool stutter_wait(const char *title)
>  			while (READ_ONCE(stutter_pause_test)) {
>  				if (!(i++ & 0xffff))
>  					torture_hrtimeout_us(10, 0, NULL);
> -				cond_resched();
>  			}
>  		} else {
>  			torture_hrtimeout_jiffies(round_jiffies_relative(HZ), NULL);
> -- 
> 2.31.1
>
diff mbox series

Patch

diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index ffdb30495e3c..737620bbec83 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -672,8 +672,6 @@  kfree_scale_thread(void *arg)
 			else
 				kfree_rcu(alloc_ptr, rh);
 		}
-
-		cond_resched();
 	} while (!torture_must_stop() && ++loop < kfree_loops);
 
 	if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index ade42d6a9d9b..158d58710b51 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -81,7 +81,7 @@  torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
-torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
+torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched_stall() behind need_resched()");
 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
 torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
@@ -2611,7 +2611,7 @@  static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
 		return;
 	}
 	// No userspace emulation: CB invocation throttles call_rcu()
-	cond_resched();
+	cond_resched_stall();
 }
 
 /*
@@ -2691,7 +2691,7 @@  static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
 		udelay(10);
 		cur_ops->readunlock(idx);
 		if (!fwd_progress_need_resched || need_resched())
-			cond_resched();
+			cond_resched_stall();
 	}
 	(*tested_tries)++;
 	if (!time_before(jiffies, stopat) &&
@@ -3232,7 +3232,7 @@  static int rcu_torture_read_exit(void *unused)
 				errexit = true;
 				break;
 			}
-			cond_resched();
+			cond_resched_stall();
 			kthread_stop(tsp);
 			n_read_exits++;
 		}
diff --git a/kernel/scftorture.c b/kernel/scftorture.c
index 59032aaccd18..24192fe01125 100644
--- a/kernel/scftorture.c
+++ b/kernel/scftorture.c
@@ -487,7 +487,6 @@  static int scftorture_invoker(void *arg)
 			set_cpus_allowed_ptr(current, cpumask_of(cpu));
 			was_offline = false;
 		}
-		cond_resched();
 		stutter_wait("scftorture_invoker");
 	} while (!torture_must_stop());
 
diff --git a/kernel/torture.c b/kernel/torture.c
index b28b05bbef02..0c0224c76275 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -747,7 +747,6 @@  bool stutter_wait(const char *title)
 			while (READ_ONCE(stutter_pause_test)) {
 				if (!(i++ & 0xffff))
 					torture_hrtimeout_us(10, 0, NULL);
-				cond_resched();
 			}
 		} else {
 			torture_hrtimeout_jiffies(round_jiffies_relative(HZ), NULL);