[PATCH 0/3] RCU refscale update for v6.7

[PATCH 0/3] RCU refscale update for v6.7

[Frederic Weisbecker]

Hello,

Please find below the RCU reference scalability test updates for the
next merge window:

Paul E. McKenney (3):
  refscale: Fix misplaced data re-read
  refscale: Print out additional module parameters
  doc: Add refscale.lookup_instances to kernel-parameters.txt

Thanks,
        Frederic.

 Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
 kernel/rcu/refscale.c                           | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

-- 
2.34.1

[PATCH 1/3] refscale: Fix misplaced data re-read

[Frederic Weisbecker]

From: "Paul E. McKenney" <paulmck@kernel.org>

This commit fixes a misplaced data re-read in the typesafe code.
The reason that this was not noticed is that this is a performance test
with no writers, so a mismatch could not occur.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/rcu/refscale.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index 91a0fd0d4d9a..750a63e99539 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -655,12 +655,12 @@ static void typesafe_delay_section(const int nloops, const int udl, const int nd
 			goto retry;
 		}
 		un_delay(udl, ndl);
+		b = READ_ONCE(rtsp->a);
 		// Remember, seqlock read-side release can fail.
 		if (!rts_release(rtsp, start)) {
 			rcu_read_unlock();
 			goto retry;
 		}
-		b = READ_ONCE(rtsp->a);
 		WARN_ONCE(a != b, "Re-read of ->a changed from %u to %u.\n", a, b);
 		b = rtsp->b;
 		rcu_read_unlock();
-- 
2.34.1

[PATCH 2/3] refscale: Print out additional module parameters

[Frederic Weisbecker]

From: "Paul E. McKenney" <paulmck@kernel.org>

The refscale.verbose_batched and refscale.lookup_instances module
parameters are omitted from the ref_scale_print_module_parms()
beginning-of-test output.  This commit therefore adds them.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/rcu/refscale.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index 750a63e99539..2c2648a3ad30 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -1025,8 +1025,8 @@ static void
 ref_scale_print_module_parms(struct ref_scale_ops *cur_ops, const char *tag)
 {
 	pr_alert("%s" SCALE_FLAG
-		 "--- %s:  verbose=%d shutdown=%d holdoff=%d loops=%ld nreaders=%d nruns=%d readdelay=%d\n", scale_type, tag,
-		 verbose, shutdown, holdoff, loops, nreaders, nruns, readdelay);
+		 "--- %s:  verbose=%d verbose_batched=%d shutdown=%d holdoff=%d lookup_instances=%ld loops=%ld nreaders=%d nruns=%d readdelay=%d\n", scale_type, tag,
+		 verbose, verbose_batched, shutdown, holdoff, lookup_instances, loops, nreaders, nruns, readdelay);
 }
 
 static void
-- 
2.34.1

[PATCH 3/3] doc: Add refscale.lookup_instances to kernel-parameters.txt

[Frederic Weisbecker]

From: "Paul E. McKenney" <paulmck@kernel.org>

This commit adds refscale.lookup_instances to kernel-parameters.txt.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0a1731a0f0ef..cf4f3262ce31 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5422,6 +5422,12 @@
 			test until boot completes in order to avoid
 			interference.
 
+	refscale.lookup_instances= [KNL]
+			Number of data elements to use for the forms of
+			SLAB_TYPESAFE_BY_RCU testing.  A negative number
+			is negated and multiplied by nr_cpu_ids, while
+			zero specifies nr_cpu_ids.
+
 	refscale.loops= [KNL]
 			Set the number of loops over the synchronization
 			primitive under test.  Increasing this number
-- 
2.34.1