From: Mark Brown <broonie@kernel.org>
To: "Paul E. McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Uladzislau Rezki <urezki@gmail.com>
Cc: Joel Fernandes <joelagnelf@nvidia.com>,
Kees Cook <kees@kernel.org>, Kees Cook <kees+treewide@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Next Mailing List <linux-next@vger.kernel.org>
Subject: linux-next: manual merge of the rcu tree with the origin tree
Date: Tue, 10 Nov 2026 19:40:19 +0000 [thread overview]
Message-ID: <avNzIwARUFPlPyrF@sirena.org.uk> (raw)
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Hi all,
Today's linux-next merge of the rcu tree got a conflict in:
kernel/rcu/rcuscale.c
between commit:
0af298e62e5cf ("treewide: refresh kmalloc_obj() conversions")
from the origin tree and commit:
08fa1784740f6 ("rcuscale: Consolidate per-writer arrays into struct writer_state")
from the rcu tree. Kees, let me once more renew my complaints about
this being done at -rc2...
I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging. You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.
diff --combined kernel/rcu/rcuscale.c
index 38c75c37a07c3,5659eaebc5c0d..0000000000000
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@@ -115,17 -115,21 +115,21 @@@ struct writer_freelist
struct writer_mblock *ws_mblocks;
};
+ struct writer_state {
+ struct writer_freelist wst_fl;
+ struct task_struct *wst_task;
+ u64 *wst_durations;
+ int wst_n_durations;
+ bool wst_done;
+ };
+
static int nrealreaders;
static int nrealwriters;
static int nrealexp;
- static struct task_struct **writer_tasks;
static struct task_struct **reader_tasks;
static struct task_struct **exp_tasks;
- static u64 **writer_durations;
- static bool *writer_done;
- static struct writer_freelist *writer_freelists;
- static int *writer_n_durations;
+ static struct writer_state *writer_states;
static atomic_t n_rcu_scale_reader_started;
static atomic_t n_rcu_scale_writer_started;
static atomic_t n_rcu_scale_writer_finished;
@@@ -293,6 -297,44 +297,44 @@@ static struct rcu_scale_ops srcud_ops
.name = "srcud"
};
+ static struct srcu_struct srcua;
+
+ static int srcu_scale_atomic_read_lock(void)
+ {
+ return srcu_read_lock_atomic(srcu_ctlp);
+ }
+
+ static void srcu_scale_atomic_read_unlock(int idx)
+ {
+ srcu_read_unlock_atomic(srcu_ctlp, idx);
+ }
+
+ static void srcu_scale_atomic_synchronize(void)
+ {
+ synchronize_srcu_atomic(srcu_ctlp);
+ }
+
+ static void srcu_atomic_scale_init(void)
+ {
+ srcu_ctlp = &srcua;
+ init_srcu_struct_atomic(srcu_ctlp);
+ }
+
+ static struct rcu_scale_ops srcua_ops = {
+ .ptype = SRCU_FLAVOR,
+ .init = srcu_atomic_scale_init,
+ .cleanup = srcu_sync_scale_cleanup,
+ .readlock = srcu_scale_atomic_read_lock,
+ .readunlock = srcu_scale_atomic_read_unlock,
+ .get_gp_seq = srcu_scale_completed,
+ .gp_diff = rcu_seq_diff,
+ .exp_completed = srcu_scale_completed,
+ .sync = srcu_scale_atomic_synchronize,
+ .exp_sync = srcu_scale_atomic_synchronize,
+ .stats = srcu_scale_stats,
+ .name = "srcua"
+ };
+
#ifdef CONFIG_TASKS_RCU
/*
@@@ -504,9 -546,9 +546,9 @@@ static struct writer_mblock *rcu_scale_
struct writer_freelist *wflp;
struct writer_mblock *wmbp;
- if (WARN_ON_ONCE(!writer_freelists))
+ if (WARN_ON_ONCE(!writer_states))
return NULL;
- wflp = &writer_freelists[me];
+ wflp = &writer_states[me].wst_fl;
if (llist_empty(&wflp->ws_lhp)) {
// ->ws_lhp is private to its rcu_scale_writer task.
wmbp = container_of(llist_del_all(&wflp->ws_lhg), struct writer_mblock, wmb_node);
@@@ -560,8 -602,9 +602,9 @@@ rcu_scale_writer(void *arg
u64 t;
DEFINE_TORTURE_RANDOM(tr);
u64 *wdp;
- u64 *wdpp = writer_durations[me];
- struct writer_freelist *wflp = &writer_freelists[me];
+ struct writer_state *wsp = &writer_states[me];
+ u64 *wdpp = wsp->wst_durations;
+ struct writer_freelist *wflp = &wsp->wst_fl;
struct writer_mblock *wmbp = NULL;
VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started");
@@@ -631,7 -674,7 +674,7 @@@
started = true;
if (!done && i >= MIN_MEAS && time_after(jiffies, jdone)) {
done = true;
- WRITE_ONCE(writer_done[me], true);
+ WRITE_ONCE(wsp->wst_done, true);
sched_set_normal(current, 0);
pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n",
scale_type, SCALE_FLAG, me, MIN_MEAS);
@@@ -649,7 -692,7 +692,7 @@@
cur_ops->get_gp_seq();
}
if (shutdown_secs) {
- writer_tasks[me] = NULL;
+ wsp->wst_task = NULL;
smp_mb(); /* Assign before wake. */
rcu_scale_cleanup();
kernel_power_off();
@@@ -665,10 -708,10 +708,10 @@@
if (!atomic_xchg(&dumped, 1)) {
for (i = 0; i < nrealwriters; i++) {
- if (writer_done[i])
+ if (writer_states[i].wst_done)
continue;
pr_info("%s: Task %ld flags writer %d:\n", __func__, me, i);
- sched_show_task(writer_tasks[i]);
+ sched_show_task(writer_states[i].wst_task);
}
if (cur_ops->stats)
cur_ops->stats();
@@@ -676,7 -719,7 +719,7 @@@
}
if (!selfreport && time_after(jiffies, jdone + HZ * (70 + me))) {
pr_info("%s: Writer %ld self-report: started %d done %d/%d->%d i %d jdone %lu.\n",
- __func__, me, started, done, writer_done[me], atomic_read(&n_rcu_scale_writer_finished), i, jiffies - jdone);
+ __func__, me, started, done, wsp->wst_done, atomic_read(&n_rcu_scale_writer_finished), i, jiffies - jdone);
selfreport = true;
}
if (gp_succeeded && started && !alldone && i < MAX_MEAS - 1)
@@@ -687,7 -730,7 +730,7 @@@
rcu_scale_free(wmbp);
cur_ops->gp_barrier();
}
- writer_n_durations[me] = i_max + 1;
+ wsp->wst_n_durations = i_max + 1;
torture_kthread_stopping("rcu_scale_writer");
return 0;
}
@@@ -1031,13 -1074,11 +1074,11 @@@ rcu_scale_cleanup(void
reader_tasks = NULL;
}
- if (writer_tasks) {
+ if (writer_states) {
for (i = 0; i < nrealwriters; i++) {
torture_stop_kthread(rcu_scale_writer,
- writer_tasks[i]);
- if (!writer_n_durations)
- continue;
- j = writer_n_durations[i];
+ writer_states[i].wst_task);
+ j = writer_states[i].wst_n_durations;
pr_alert("%s%s writer %d gps: %d\n",
scale_type, SCALE_FLAG, i, j);
ngps += j;
@@@ -1051,14 -1092,12 +1092,12 @@@
rcuscale_seq_diff(b_rcu_gp_test_finished,
b_rcu_gp_test_started));
for (i = 0; i < nrealwriters; i++) {
- if (!writer_durations)
- break;
- if (!writer_n_durations)
- continue;
- wdpp = writer_durations[i];
+ struct writer_state *wsp = &writer_states[i];
+
+ wdpp = wsp->wst_durations;
if (!wdpp)
continue;
- for (j = 0; j < writer_n_durations[i]; j++) {
+ for (j = 0; j < wsp->wst_n_durations; j++) {
wdp = &wdpp[j];
pr_alert("%s%s %4d writer-duration: %5d %llu\n",
scale_type, SCALE_FLAG,
@@@ -1066,34 -1105,23 +1105,23 @@@
if (j % 100 == 0)
schedule_timeout_uninterruptible(1);
}
- kfree(writer_durations[i]);
- if (writer_freelists) {
+ kfree(wdpp);
+ if (wsp->wst_fl.ws_mblocks) {
int ctr = 0;
struct llist_node *llnp;
- struct writer_freelist *wflp = &writer_freelists[i];
- if (wflp->ws_mblocks) {
- llist_for_each(llnp, wflp->ws_lhg.first)
- ctr++;
- llist_for_each(llnp, wflp->ws_lhp.first)
- ctr++;
- WARN_ONCE(ctr != gp_async_max,
- "%s: ctr = %d gp_async_max = %d\n",
- __func__, ctr, gp_async_max);
- kfree(wflp->ws_mblocks);
- }
+ llist_for_each(llnp, wsp->wst_fl.ws_lhg.first)
+ ctr++;
+ llist_for_each(llnp, wsp->wst_fl.ws_lhp.first)
+ ctr++;
+ WARN_ONCE(ctr != gp_async_max,
+ "%s: ctr = %d gp_async_max = %d\n",
+ __func__, ctr, gp_async_max);
+ kfree(wsp->wst_fl.ws_mblocks);
}
}
- kfree(writer_tasks);
- writer_tasks = NULL;
- kfree(writer_durations);
- writer_durations = NULL;
- kfree(writer_n_durations);
- writer_n_durations = NULL;
- kfree(writer_done);
- writer_done = NULL;
- kfree(writer_freelists);
- writer_freelists = NULL;
+ kfree(writer_states);
+ writer_states = NULL;
}
/* Do torture-type-specific cleanup operations. */
@@@ -1110,7 -1138,8 +1138,8 @@@ rcu_scale_init(void
long i;
long j;
static struct rcu_scale_ops *scale_ops[] = {
- &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
+ &rcu_ops, &srcu_ops, &srcua_ops, &srcud_ops,
+ TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
};
if (!torture_init_begin(scale_type, verbose))
@@@ -1187,36 -1216,30 +1216,30 @@@
goto unwind;
}
}
- writer_tasks = kzalloc_objs(writer_tasks[0], nrealwriters);
- writer_durations = kzalloc_objs(*writer_durations, nrealwriters);
- writer_n_durations = kzalloc_objs(*writer_n_durations, nrealwriters);
- writer_done = kzalloc_objs(writer_done[0], nrealwriters);
- if (gp_async) {
- if (gp_async_max <= 0) {
- pr_warn("%s: gp_async_max = %d must be greater than zero.\n",
- __func__, gp_async_max);
- WARN_ON_ONCE(IS_BUILTIN(CONFIG_RCU_TORTURE_TEST));
- firsterr = -EINVAL;
- goto unwind;
- }
- writer_freelists = kzalloc_objs(writer_freelists[0],
- nrealwriters);
+ writer_states = kzalloc_objs(writer_states[0], nrealwriters);
+ if (gp_async && gp_async_max <= 0) {
+ pr_warn("%s: gp_async_max = %d must be greater than zero.\n",
+ __func__, gp_async_max);
+ WARN_ON_ONCE(IS_BUILTIN(CONFIG_RCU_TORTURE_TEST));
+ firsterr = -EINVAL;
+ goto unwind;
}
- if (!writer_tasks || !writer_durations || !writer_n_durations || !writer_done ||
- (gp_async && !writer_freelists)) {
+ if (!writer_states) {
SCALEOUT_ERRSTRING("out of memory");
firsterr = -ENOMEM;
goto unwind;
}
for (i = 0; i < nrealwriters; i++) {
- writer_durations[i] =
- kzalloc_objs(*writer_durations[i], MAX_MEAS);
- if (!writer_durations[i]) {
+ struct writer_state *wsp = &writer_states[i];
+
+ wsp->wst_durations = kcalloc(MAX_MEAS, sizeof(*wsp->wst_durations),
+ GFP_KERNEL);
+ if (!wsp->wst_durations) {
firsterr = -ENOMEM;
goto unwind;
}
- if (writer_freelists) {
- struct writer_freelist *wflp = &writer_freelists[i];
+ if (gp_async) {
+ struct writer_freelist *wflp = &wsp->wst_fl;
init_llist_head(&wflp->ws_lhg);
init_llist_head(&wflp->ws_lhp);
@@@ -1234,7 -1257,7 +1257,7 @@@
}
}
firsterr = torture_create_kthread(rcu_scale_writer, (void *)i,
- writer_tasks[i]);
+ wsp->wst_task);
if (torture_init_error(firsterr))
goto unwind;
}
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next reply other threads:[~2026-11-10 19:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-10 19:40 Mark Brown [this message]
2026-11-10 20:17 ` Joel Fernandes
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