RCU Archive on lore.kernel.org
 help / color / Atom feed
From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
	mingo@kernel.org, jiangshanlai@gmail.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
	"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 05/17] rcutorture: Make synctype[] and nsynctype be static global
Date: Wed,  6 Jan 2021 09:16:58 -0800
Message-ID: <20210106171710.22239-5-paulmck@kernel.org> (raw)
In-Reply-To: <20210106171532.GA20769@paulmck-ThinkPad-P72>

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

Full testing of the new SRCU polling API requires that the fake writers
also use it in order to test concurrent calls to all of the API members,
especially start_poll_synchronize_srcu().  This commit prepares the ground
for this by making the synctype[] and nsynctype variables be static
globals so that the rcu_torture_fakewriter() function can access them.
Initialization of these variables is moved from rcu_torture_writer()
to a new rcu_torture_write_types() function that is invoked from
rcu_torture_init() just before the first writer kthread is spawned.

Link: https://lore.kernel.org/rcu/20201112201547.GF3365678@moria.home.lan/
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/rcutorture.c | 62 ++++++++++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 26 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 1930d92..ea44a2b 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1062,37 +1062,18 @@ rcu_torture_fqs(void *arg)
 	return 0;
 }
 
+// Used by writers to randomly choose from the available grace-period
+// primitives.  The only purpose of the initialization is to size the array.
+static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC };
+static int nsynctypes = 0;
+
 /*
- * RCU torture writer kthread.  Repeatedly substitutes a new structure
- * for that pointed to by rcu_torture_current, freeing the old structure
- * after a series of grace periods (the "pipeline").
+ * Determine which grace-period primitives are available.
  */
-static int
-rcu_torture_writer(void *arg)
+static void rcu_torture_write_types(void)
 {
-	bool boot_ended;
-	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
-	unsigned long cookie;
-	int expediting = 0;
-	unsigned long gp_snap;
 	bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
 	bool gp_poll1 = gp_poll, gp_sync1 = gp_sync;
-	int i;
-	int idx;
-	int oldnice = task_nice(current);
-	struct rcu_torture *rp;
-	struct rcu_torture *old_rp;
-	static DEFINE_TORTURE_RANDOM(rand);
-	bool stutter_waited;
-	int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
-			   RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC };
-	int nsynctypes = 0;
-
-	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
-	if (!can_expedite)
-		pr_alert("%s" TORTURE_FLAG
-			 " GP expediting controlled from boot/sysfs for %s.\n",
-			 torture_type, cur_ops->name);
 
 	/* Initialize synctype[] array.  If none set, take default. */
 	if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1)
@@ -1127,6 +1108,34 @@ rcu_torture_writer(void *arg)
 	} else if (gp_sync && !cur_ops->sync) {
 		pr_alert("%s: gp_sync without primitives.\n", __func__);
 	}
+}
+
+/*
+ * RCU torture writer kthread.  Repeatedly substitutes a new structure
+ * for that pointed to by rcu_torture_current, freeing the old structure
+ * after a series of grace periods (the "pipeline").
+ */
+static int
+rcu_torture_writer(void *arg)
+{
+	bool boot_ended;
+	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
+	unsigned long cookie;
+	int expediting = 0;
+	unsigned long gp_snap;
+	int i;
+	int idx;
+	int oldnice = task_nice(current);
+	struct rcu_torture *rp;
+	struct rcu_torture *old_rp;
+	static DEFINE_TORTURE_RANDOM(rand);
+	bool stutter_waited;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
+	if (!can_expedite)
+		pr_alert("%s" TORTURE_FLAG
+			 " GP expediting controlled from boot/sysfs for %s.\n",
+			 torture_type, cur_ops->name);
 	if (WARN_ONCE(nsynctypes == 0,
 		      "rcu_torture_writer: No update-side primitives.\n")) {
 		/*
@@ -2889,6 +2898,7 @@ rcu_torture_init(void)
 
 	/* Start up the kthreads. */
 
+	rcu_torture_write_types();
 	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
 					  writer_task);
 	if (firsterr)
-- 
2.9.5


  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-06 17:15 [PATCH tip/core/rcu 0/17] Torture-test updates for v5.12 Paul E. McKenney
2021-01-06 17:16 ` [PATCH tip/core/rcu 01/17] rcutorture: Add testing for RCU's global memory ordering paulmck
2021-01-06 17:16 ` [PATCH tip/core/rcu 02/17] scftorture: Add debug output for wrong-CPU warning paulmck
2021-01-06 17:16 ` [PATCH tip/core/rcu 03/17] refscale: Allow summarization of verbose output paulmck
2021-01-06 17:16 ` [PATCH tip/core/rcu 04/17] rcutorture: Require entire stutter period be post-boot paulmck
2021-01-06 17:16 ` paulmck [this message]
2021-01-06 17:16 ` [PATCH tip/core/rcu 06/17] rcutorture: Make rcu_torture_fakewriter() use blocking wait primitives paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 07/17] torture: Add fuzzed hrtimer-based sleep functions paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 08/17] rcutorture: Use torture_hrtimeout_jiffies() to avoid busy-waits paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 09/17] torture: Make stutter use torture_hrtimeout_*() functions paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 10/17] rcutorture: Use hrtimers for reader and writer delays paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 11/17] torture: Make refscale throttle high-rate printk()s paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 12/17] torture: Throttle VERBOSE_TOROUT_*() output paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 13/17] rcutorture: Make object_debug also double call_rcu() heap object paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 14/17] torture: Clean up after torture-test CPU hotplugging paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 15/17] torture: Maintain torture-specific set of CPUs-online books paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 16/17] torture: Break affinity of kthreads last running on outgoing CPU paulmck
2021-01-06 17:17 ` [PATCH tip/core/rcu 17/17] rcutorture: Add rcutree.use_softirq=0 to RUDE01 and TASKS01 paulmck

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210106171710.22239-5-paulmck@kernel.org \
    --to=paulmck@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=dhowells@redhat.com \
    --cc=edumazet@google.com \
    --cc=fweisbec@gmail.com \
    --cc=jiangshanlai@gmail.com \
    --cc=joel@joelfernandes.org \
    --cc=josh@joshtriplett.org \
    --cc=kernel-team@fb.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=mingo@kernel.org \
    --cc=oleg@redhat.com \
    --cc=peterz@infradead.org \
    --cc=rcu@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

RCU Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/rcu/0 rcu/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 rcu rcu/ https://lore.kernel.org/rcu \
		rcu@vger.kernel.org
	public-inbox-index rcu

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.rcu


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git