6.5-stable review patch. If anyone has any objections, please let me know.
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From: Dietmar Eggemann dietmar.eggemann@arm.com
[ Upstream commit 5d248bb39fe1388943acb6510f8f48fa5570e0ec ]
This commit adds a module parameter that causes the locktorture writer to run at real-time priority.
To use it: insmod /lib/modules/torture.ko random_shuffle=1 insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1 ^^^^^^^^^^^^^
A predecessor to this patch has been helpful to uncover issues with the proxy-execution series.
[ paulmck: Remove locktorture-specific code from kernel/torture.c. ]
Cc: "Paul E. McKenney" paulmck@kernel.org Cc: Josh Triplett josh@joshtriplett.org Cc: Joel Fernandes joel@joelfernandes.org Cc: Juri Lelli juri.lelli@redhat.com Cc: Valentin Schneider vschneid@redhat.com Cc: kernel-team@android.com Signed-off-by: Dietmar Eggemann dietmar.eggemann@arm.com [jstultz: Include header change to build, reword commit message] Signed-off-by: John Stultz jstultz@google.com Acked-by: Davidlohr Bueso dave@stgolabs.net Signed-off-by: Paul E. McKenney paulmck@kernel.org Stable-dep-of: cca42bd8eb1b ("rcutorture: Fix stuttering races and other issues") Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ kernel/locking/locktorture.c | 12 +++++++----- kernel/torture.c | 3 ++- 3 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b951b4c2808f1..5711129686d10 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2938,6 +2938,10 @@ locktorture.torture_type= [KNL] Specify the locking implementation to test.
+ locktorture.writer_fifo= [KNL] + Run the write-side locktorture kthreads at + sched_set_fifo() real-time priority. + locktorture.verbose= [KNL] Enable additional printk() statements.
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 949d3deae5062..270c7f80ce84c 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -45,6 +45,7 @@ torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable"); torture_param(int, rt_boost, 2, "Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types."); torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens."); +torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority"); torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)"); /* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */ @@ -809,7 +810,8 @@ static int lock_torture_writer(void *arg) bool skip_main_lock;
VERBOSE_TOROUT_STRING("lock_torture_writer task started"); - set_user_nice(current, MAX_NICE); + if (!rt_task(current)) + set_user_nice(current, MAX_NICE);
do { if ((torture_random(&rand) & 0xfffff) == 0) @@ -1015,8 +1017,7 @@ static void lock_torture_cleanup(void)
if (writer_tasks) { for (i = 0; i < cxt.nrealwriters_stress; i++) - torture_stop_kthread(lock_torture_writer, - writer_tasks[i]); + torture_stop_kthread(lock_torture_writer, writer_tasks[i]); kfree(writer_tasks); writer_tasks = NULL; } @@ -1244,8 +1245,9 @@ static int __init lock_torture_init(void) goto create_reader;
/* Create writer. */ - firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i], - writer_tasks[i]); + firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i], + writer_tasks[i], + writer_fifo ? sched_set_fifo : NULL); if (torture_init_error(firsterr)) goto unwind;
diff --git a/kernel/torture.c b/kernel/torture.c index 1da48f3816f61..e06b03e987c9f 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -37,6 +37,7 @@ #include <linux/ktime.h> #include <asm/byteorder.h> #include <linux/torture.h> +#include <linux/sched/rt.h> #include "rcu/rcu.h"
MODULE_LICENSE("GPL"); @@ -728,7 +729,7 @@ bool stutter_wait(const char *title) cond_resched_tasks_rcu_qs(); spt = READ_ONCE(stutter_pause_test); for (; spt; spt = READ_ONCE(stutter_pause_test)) { - if (!ret) { + if (!ret && !rt_task(current)) { sched_set_normal(current, MAX_NICE); ret = true; }