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-rw-r--r--kernel/rcu/Kconfig3
-rw-r--r--kernel/rcu/rcu.h6
-rw-r--r--kernel/rcu/rcuscale.c9
-rw-r--r--kernel/rcu/rcutorture.c234
-rw-r--r--kernel/rcu/refscale.c2
-rw-r--r--kernel/rcu/srcutiny.c2
-rw-r--r--kernel/rcu/srcutree.c404
-rw-r--r--kernel/rcu/tasks.h33
-rw-r--r--kernel/rcu/tree.c16
-rw-r--r--kernel/rcu/tree_exp.h16
-rw-r--r--kernel/rcu/tree_nocb.h4
11 files changed, 507 insertions, 222 deletions
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index ab62074174c3..9071182b1284 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -53,9 +53,6 @@ config RCU_EXPERT
Say N if you are unsure.
-config SRCU
- def_bool y
-
config TINY_SRCU
bool
default y if TINY_RCU
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index a3adcf9a9919..4a1b9622598b 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -378,11 +378,13 @@ extern void rcu_init_geometry(void);
* specified state structure (for SRCU) or the only rcu_state structure
* (for RCU).
*/
-#define srcu_for_each_node_breadth_first(sp, rnp) \
+#define _rcu_for_each_node_breadth_first(sp, rnp) \
for ((rnp) = &(sp)->node[0]; \
(rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
#define rcu_for_each_node_breadth_first(rnp) \
- srcu_for_each_node_breadth_first(&rcu_state, rnp)
+ _rcu_for_each_node_breadth_first(&rcu_state, rnp)
+#define srcu_for_each_node_breadth_first(ssp, rnp) \
+ _rcu_for_each_node_breadth_first(ssp->srcu_sup, rnp)
/*
* Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index 91fb5905a008..e82ec9f9a5d8 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -631,8 +631,7 @@ static int compute_real(int n)
static int
rcu_scale_shutdown(void *arg)
{
- wait_event(shutdown_wq,
- atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters);
+ wait_event_idle(shutdown_wq, atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters);
smp_mb(); /* Wake before output. */
rcu_scale_cleanup();
kernel_power_off();
@@ -716,7 +715,7 @@ kfree_scale_thread(void *arg)
// is tested.
if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
(kfree_rcu_test_both && torture_random(&tr) & 0x800))
- kfree_rcu(alloc_ptr);
+ kfree_rcu_mightsleep(alloc_ptr);
else
kfree_rcu(alloc_ptr, rh);
}
@@ -771,8 +770,8 @@ kfree_scale_cleanup(void)
static int
kfree_scale_shutdown(void *arg)
{
- wait_event(shutdown_wq,
- atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
+ wait_event_idle(shutdown_wq,
+ atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
smp_mb(); /* Wake before output. */
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 8e6c023212cb..147551c23baf 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -119,7 +119,9 @@ torture_param(int, stutter, 5, "Number of seconds to run/halt test");
torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
+torture_param(int, test_nmis, 0, "End-test NMI tests, 0 to disable.");
torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
+torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario.");
torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
static char *torture_type = "rcu";
@@ -179,7 +181,6 @@ static atomic_t n_rcu_torture_mbchk_tries;
static atomic_t n_rcu_torture_error;
static long n_rcu_torture_barrier_error;
static long n_rcu_torture_boost_ktrerror;
-static long n_rcu_torture_boost_rterror;
static long n_rcu_torture_boost_failure;
static long n_rcu_torture_boosts;
static atomic_long_t n_rcu_torture_timers;
@@ -2194,12 +2195,11 @@ rcu_torture_stats_print(void)
atomic_read(&n_rcu_torture_alloc),
atomic_read(&n_rcu_torture_alloc_fail),
atomic_read(&n_rcu_torture_free));
- pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ",
+ pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ",
atomic_read(&n_rcu_torture_mberror),
atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
n_rcu_torture_barrier_error,
- n_rcu_torture_boost_ktrerror,
- n_rcu_torture_boost_rterror);
+ n_rcu_torture_boost_ktrerror);
pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
n_rcu_torture_boost_failure,
n_rcu_torture_boosts,
@@ -2217,15 +2217,13 @@ rcu_torture_stats_print(void)
if (atomic_read(&n_rcu_torture_mberror) ||
atomic_read(&n_rcu_torture_mbchk_fail) ||
n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
- n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
- i > 1) {
+ n_rcu_torture_boost_failure || i > 1) {
pr_cont("%s", "!!! ");
atomic_inc(&n_rcu_torture_error);
WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
- WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
WARN_ON_ONCE(i > 1); // Too-short grace period
}
@@ -2358,7 +2356,8 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
"n_barrier_cbs=%d "
"onoff_interval=%d onoff_holdoff=%d "
"read_exit_delay=%d read_exit_burst=%d "
- "nocbs_nthreads=%d nocbs_toggle=%d\n",
+ "nocbs_nthreads=%d nocbs_toggle=%d "
+ "test_nmis=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
@@ -2369,7 +2368,8 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
n_barrier_cbs,
onoff_interval, onoff_holdoff,
read_exit_delay, read_exit_burst,
- nocbs_nthreads, nocbs_toggle);
+ nocbs_nthreads, nocbs_toggle,
+ test_nmis);
}
static int rcutorture_booster_cleanup(unsigned int cpu)
@@ -3273,6 +3273,29 @@ static void rcu_torture_read_exit_cleanup(void)
torture_stop_kthread(rcutorture_read_exit, read_exit_task);
}
+static void rcutorture_test_nmis(int n)
+{
+#if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
+ int cpu;
+ int dumpcpu;
+ int i;
+
+ for (i = 0; i < n; i++) {
+ preempt_disable();
+ cpu = smp_processor_id();
+ dumpcpu = cpu + 1;
+ if (dumpcpu >= nr_cpu_ids)
+ dumpcpu = 0;
+ pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu);
+ dump_cpu_task(dumpcpu);
+ preempt_enable();
+ schedule_timeout_uninterruptible(15 * HZ);
+ }
+#else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
+ WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis);
+#endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
+}
+
static enum cpuhp_state rcutor_hp;
static void
@@ -3297,6 +3320,8 @@ rcu_torture_cleanup(void)
return;
}
+ rcutorture_test_nmis(test_nmis);
+
if (cur_ops->gp_kthread_dbg)
cur_ops->gp_kthread_dbg();
rcu_torture_read_exit_cleanup();
@@ -3463,6 +3488,188 @@ static void rcutorture_sync(void)
cur_ops->sync();
}
+static DEFINE_MUTEX(mut0);
+static DEFINE_MUTEX(mut1);
+static DEFINE_MUTEX(mut2);
+static DEFINE_MUTEX(mut3);
+static DEFINE_MUTEX(mut4);
+static DEFINE_MUTEX(mut5);
+static DEFINE_MUTEX(mut6);
+static DEFINE_MUTEX(mut7);
+static DEFINE_MUTEX(mut8);
+static DEFINE_MUTEX(mut9);
+
+static DECLARE_RWSEM(rwsem0);
+static DECLARE_RWSEM(rwsem1);
+static DECLARE_RWSEM(rwsem2);
+static DECLARE_RWSEM(rwsem3);
+static DECLARE_RWSEM(rwsem4);
+static DECLARE_RWSEM(rwsem5);
+static DECLARE_RWSEM(rwsem6);
+static DECLARE_RWSEM(rwsem7);
+static DECLARE_RWSEM(rwsem8);
+static DECLARE_RWSEM(rwsem9);
+
+DEFINE_STATIC_SRCU(srcu0);
+DEFINE_STATIC_SRCU(srcu1);
+DEFINE_STATIC_SRCU(srcu2);
+DEFINE_STATIC_SRCU(srcu3);
+DEFINE_STATIC_SRCU(srcu4);
+DEFINE_STATIC_SRCU(srcu5);
+DEFINE_STATIC_SRCU(srcu6);
+DEFINE_STATIC_SRCU(srcu7);
+DEFINE_STATIC_SRCU(srcu8);
+DEFINE_STATIC_SRCU(srcu9);
+
+static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
+ int cyclelen, int deadlock)
+{
+ int j = i + 1;
+
+ if (j >= cyclelen)
+ j = deadlock ? 0 : -1;
+ if (j >= 0)
+ pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i);
+ else
+ pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i);
+ return j;
+}
+
+// Test lockdep on SRCU-based deadlock scenarios.
+static void rcu_torture_init_srcu_lockdep(void)
+{
+ int cyclelen;
+ int deadlock;
+ bool err = false;
+ int i;
+ int j;
+ int idx;
+ struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4,
+ &mut5, &mut6, &mut7, &mut8, &mut9 };
+ struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4,
+ &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
+ struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
+ &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
+ int testtype;
+
+ if (!test_srcu_lockdep)
+ return;
+
+ deadlock = test_srcu_lockdep / 1000;
+ testtype = (test_srcu_lockdep / 10) % 100;
+ cyclelen = test_srcu_lockdep % 10;
+ WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus));
+ if (WARN_ONCE(deadlock != !!deadlock,
+ "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n",
+ __func__, test_srcu_lockdep, deadlock))
+ err = true;
+ if (WARN_ONCE(cyclelen <= 0,
+ "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n",
+ __func__, test_srcu_lockdep, cyclelen))
+ err = true;
+ if (err)
+ goto err_out;
+
+ if (testtype == 0) {
+ pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n",
+ __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
+ if (deadlock && cyclelen == 1)
+ pr_info("%s: Expect hang.\n", __func__);
+ for (i = 0; i < cyclelen; i++) {
+ j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu",
+ "srcu_read_unlock", i, cyclelen, deadlock);
+ idx = srcu_read_lock(srcus[i]);
+ if (j >= 0)
+ synchronize_srcu(srcus[j]);
+ srcu_read_unlock(srcus[i], idx);
+ }
+ return;
+ }
+
+ if (testtype == 1) {
+ pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n",
+ __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
+ for (i = 0; i < cyclelen; i++) {
+ pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n",
+ __func__, i, i, i, i);
+ idx = srcu_read_lock(srcus[i]);
+ mutex_lock(muts[i]);
+ mutex_unlock(muts[i]);
+ srcu_read_unlock(srcus[i], idx);
+
+ j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu",
+ "mutex_unlock", i, cyclelen, deadlock);
+ mutex_lock(muts[i]);
+ if (j >= 0)
+ synchronize_srcu(srcus[j]);
+ mutex_unlock(muts[i]);
+ }
+ return;
+ }
+
+ if (testtype == 2) {
+ pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n",
+ __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
+ for (i = 0; i < cyclelen; i++) {
+ pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n",
+ __func__, i, i, i, i);
+ idx = srcu_read_lock(srcus[i]);
+ down_read(rwsems[i]);
+ up_read(rwsems[i]);
+ srcu_read_unlock(srcus[i], idx);
+
+ j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu",
+ "up_write", i, cyclelen, deadlock);
+ down_write(rwsems[i]);
+ if (j >= 0)
+ synchronize_srcu(srcus[j]);
+ up_write(rwsems[i]);
+ }
+ return;
+ }
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+ if (testtype == 3) {
+ pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n",
+ __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
+ if (deadlock && cyclelen == 1)
+ pr_info("%s: Expect hang.\n", __func__);
+ for (i = 0; i < cyclelen; i++) {
+ char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock";
+ char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace"
+ : "synchronize_srcu";
+ char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock";
+
+ j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock);
+ if (i == 0)
+ rcu_read_lock_trace();
+ else
+ idx = srcu_read_lock(srcus[i]);
+ if (j >= 0) {
+ if (i == cyclelen - 1)
+ synchronize_rcu_tasks_trace();
+ else
+ synchronize_srcu(srcus[j]);
+ }
+ if (i == 0)
+ rcu_read_unlock_trace();
+ else
+ srcu_read_unlock(srcus[i], idx);
+ }
+ return;
+ }
+#endif // #ifdef CONFIG_TASKS_TRACE_RCU
+
+err_out:
+ pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
+ pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
+ pr_info("%s: D: Deadlock if nonzero.\n", __func__);
+ pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__);
+ pr_info("%s: L: Cycle length.\n", __func__);
+ if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU))
+ pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__);
+}
+
static int __init
rcu_torture_init(void)
{
@@ -3501,9 +3708,17 @@ rcu_torture_init(void)
pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
fqs_duration = 0;
}
+ if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops ||
+ !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
+ pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n",
+ cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU));
+ nocbs_nthreads = 0;
+ }
if (cur_ops->init)
cur_ops->init();
+ rcu_torture_init_srcu_lockdep();
+
if (nreaders >= 0) {
nrealreaders = nreaders;
} else {
@@ -3540,7 +3755,6 @@ rcu_torture_init(void)
atomic_set(&n_rcu_torture_error, 0);
n_rcu_torture_barrier_error = 0;
n_rcu_torture_boost_ktrerror = 0;
- n_rcu_torture_boost_rterror = 0;
n_rcu_torture_boost_failure = 0;
n_rcu_torture_boosts = 0;
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index afa3e1a2f690..1970ce5f22d4 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -1031,7 +1031,7 @@ ref_scale_cleanup(void)
static int
ref_scale_shutdown(void *arg)
{
- wait_event(shutdown_wq, shutdown_start);
+ wait_event_idle(shutdown_wq, shutdown_start);
smp_mb(); // Wake before output.
ref_scale_cleanup();
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index b12fb0cec44d..336af24e0fe3 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -197,6 +197,8 @@ void synchronize_srcu(struct srcu_struct *ssp)
{
struct rcu_synchronize rs;
+ srcu_lock_sync(&ssp->dep_map);
+
RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) ||
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 68f89c533057..20d7a238d675 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -103,7 +103,7 @@ do { \
#define spin_trylock_irqsave_rcu_node(p, flags) \
({ \
- bool ___locked = spin_trylock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
+ bool ___locked = spin_trylock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
\
if (___locked) \
smp_mb__after_unlock_lock(); \
@@ -135,8 +135,8 @@ static void init_srcu_struct_data(struct srcu_struct *ssp)
spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
rcu_segcblist_init(&sdp->srcu_cblist);
sdp->srcu_cblist_invoking = false;
- sdp->srcu_gp_seq_needed = ssp->srcu_gp_seq;
- sdp->srcu_gp_seq_needed_exp = ssp->srcu_gp_seq;
+ sdp->srcu_gp_seq_needed = ssp->srcu_sup->srcu_gp_seq;
+ sdp->srcu_gp_seq_needed_exp = ssp->srcu_sup->srcu_gp_seq;
sdp->mynode = NULL;
sdp->cpu = cpu;
INIT_WORK(&sdp->work, srcu_invoke_callbacks);
@@ -173,14 +173,14 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
/* Initialize geometry if it has not already been initialized. */
rcu_init_geometry();
- ssp->node = kcalloc(rcu_num_nodes, sizeof(*ssp->node), gfp_flags);
- if (!ssp->node)
+ ssp->srcu_sup->node = kcalloc(rcu_num_nodes, sizeof(*ssp->srcu_sup->node), gfp_flags);
+ if (!ssp->srcu_sup->node)
return false;
/* Work out the overall tree geometry. */
- ssp->level[0] = &ssp->node[0];
+ ssp->srcu_sup->level[0] = &ssp->srcu_sup->node[0];
for (i = 1; i < rcu_num_lvls; i++)
- ssp->level[i] = ssp->level[i - 1] + num_rcu_lvl[i - 1];
+ ssp->srcu_sup->level[i] = ssp->srcu_sup->level[i - 1] + num_rcu_lvl[i - 1];
rcu_init_levelspread(levelspread, num_rcu_lvl);
/* Each pass through this loop initializes one srcu_node structure. */
@@ -195,17 +195,17 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
snp->srcu_gp_seq_needed_exp = SRCU_SNP_INIT_SEQ;
snp->grplo = -1;
snp->grphi = -1;
- if (snp == &ssp->node[0]) {
+ if (snp == &ssp->srcu_sup->node[0]) {
/* Root node, special case. */
snp->srcu_parent = NULL;
continue;
}
/* Non-root node. */
- if (snp == ssp->level[level + 1])
+ if (snp == ssp->srcu_sup->level[level + 1])
level++;
- snp->srcu_parent = ssp->level[level - 1] +
- (snp - ssp->level[level]) /
+ snp->srcu_parent = ssp->srcu_sup->level[level - 1] +
+ (snp - ssp->srcu_sup->level[level]) /
levelspread[level - 1];
}
@@ -214,7 +214,7 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
* leaves of the srcu_node tree.
*/
level = rcu_num_lvls - 1;
- snp_first = ssp->level[level];
+ snp_first = ssp->srcu_sup->level[level];
for_each_possible_cpu(cpu) {
sdp = per_cpu_ptr(ssp->sda, cpu);
sdp->mynode = &snp_first[cpu / levelspread[level]];
@@ -225,7 +225,7 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
}
sdp->grpmask = 1 << (cpu - sdp->mynode->grplo);
}
- smp_store_release(&ssp->srcu_size_state, SRCU_SIZE_WAIT_BARRIER);
+ smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_WAIT_BARRIER);
return true;
}
@@ -236,36 +236,47 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
*/
static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
{
- ssp->srcu_size_state = SRCU_SIZE_SMALL;
- ssp->node = NULL;
- mutex_init(&ssp->srcu_cb_mutex);
- mutex_init(&ssp->srcu_gp_mutex);
+ if (!is_static)
+ ssp->srcu_sup = kzalloc(sizeof(*ssp->srcu_sup), GFP_KERNEL);
+ if (!ssp->srcu_sup)
+ return -ENOMEM;
+ if (!is_static)
+ spin_lock_init(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
+ ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL;
+ ssp->srcu_sup->node = NULL;
+ mutex_init(&ssp->srcu_sup->srcu_cb_mutex);
+ mutex_init(&ssp->srcu_sup->srcu_gp_mutex);
ssp->srcu_idx = 0;
- ssp->srcu_gp_seq = 0;
- ssp->srcu_barrier_seq = 0;
- mutex_init(&ssp->srcu_barrier_mutex);
- atomic_set(&ssp->srcu_barrier_cpu_cnt, 0);
- INIT_DELAYED_WORK(&ssp->work, process_srcu);
- ssp->sda_is_static = is_static;
+ ssp->srcu_sup->srcu_gp_seq = 0;
+ ssp->srcu_sup->srcu_barrier_seq = 0;
+ mutex_init(&ssp->srcu_sup->srcu_barrier_mutex);
+ atomic_set(&ssp->srcu_sup->srcu_barrier_cpu_cnt, 0);
+ INIT_DELAYED_WORK(&ssp->srcu_sup->work, process_srcu);
+ ssp->srcu_sup->sda_is_static = is_static;
if (!is_static)
ssp->sda = alloc_percpu(struct srcu_data);
- if (!ssp->sda)
+ if (!ssp->sda) {
+ if (!is_static)
+ kfree(ssp->srcu_sup);
return -ENOMEM;
+ }
init_srcu_struct_data(ssp);
- ssp->srcu_gp_seq_needed_exp = 0;
- ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
- if (READ_ONCE(ssp->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) {
+ ssp->srcu_sup->srcu_gp_seq_needed_exp = 0;
+ ssp->srcu_sup->srcu_last_gp_end = ktime_get_mono_fast_ns();
+ if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) {
if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC)) {
- if (!ssp->sda_is_static) {
+ if (!ssp->srcu_sup->sda_is_static) {
free_percpu(ssp->sda);
ssp->sda = NULL;
+ kfree(ssp->srcu_sup);
return -ENOMEM;
}
} else {
- WRITE_ONCE(ssp->srcu_size_state, SRCU_SIZE_BIG);
+ WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG);
}
}
- smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
+ ssp->srcu_sup->srcu_ssp = ssp;
+ smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, 0); /* Init done. */
return 0;
}
@@ -277,7 +288,6 @@ int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
/* Don't re-initialize a lock while it is held. */
debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
lockdep_init_map(&ssp->dep_map, name, key, 0);
- spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
return init_srcu_struct_fields(ssp, false);
}
EXPORT_SYMBOL_GPL(__init_srcu_struct);
@@ -294,7 +304,6 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct);
*/
int init_srcu_struct(struct srcu_struct *ssp)
{
- spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
return init_srcu_struct_fields(ssp, false);
}
EXPORT_SYMBOL_GPL(init_srcu_struct);
@@ -306,8 +315,8 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
*/
static void __srcu_transition_to_big(struct srcu_struct *ssp)
{
- lockdep_assert_held(&ACCESS_PRIVATE(ssp, lock));
- smp_store_release(&ssp->srcu_size_state, SRCU_SIZE_ALLOC);
+ lockdep_assert_held(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
+ smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_ALLOC);
}
/*
@@ -318,15 +327,15 @@ static void srcu_transition_to_big(struct srcu_struct *ssp)
unsigned long flags;
/* Double-checked locking on ->srcu_size-state. */
- if (smp_load_acquire(&ssp->srcu_size_state) != SRCU_SIZE_SMALL)
+ if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL)
return;
- spin_lock_irqsave_rcu_node(ssp, flags);
- if (smp_load_acquire(&ssp->srcu_size_state) != SRCU_SIZE_SMALL) {
- spin_unlock_irqrestore_rcu_node(ssp, flags);
+ spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
+ if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL) {
+ spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
return;
}
__srcu_transition_to_big(ssp);
- spin_unlock_irqrestore_rcu_node(ssp, flags);
+ spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
}
/*
@@ -337,14 +346,14 @@ static void spin_lock_irqsave_check_contention(struct srcu_struct *ssp)
{
unsigned long j;
- if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_size_state)
+ if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_sup->srcu_size_state)
return;
j = jiffies;
- if (ssp->srcu_size_jiffies != j) {
- ssp->srcu_size_jiffies = j;
- ssp->srcu_n_lock_retries = 0;
+ if (ssp->srcu_sup->srcu_size_jiffies != j) {
+ ssp->srcu_sup->srcu_size_jiffies = j;
+ ssp->srcu_sup->srcu_n_lock_retries = 0;
}
- if (++ssp->srcu_n_lock_retries <= small_contention_lim)
+ if (++ssp->srcu_sup->srcu_n_lock_retries <= small_contention_lim)
return;
__srcu_transition_to_big(ssp);
}
@@ -361,9 +370,9 @@ static void spin_lock_irqsave_sdp_contention(struct srcu_data *sdp, unsigned lon
if (spin_trylock_irqsave_rcu_node(sdp, *flags))
return;
- spin_lock_irqsave_rcu_node(ssp, *flags);
+ spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags);
spin_lock_irqsave_check_contention(ssp);
- spin_unlock_irqrestore_rcu_node(ssp, *flags);
+ spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, *flags);
spin_lock_irqsave_rcu_node(sdp, *flags);
}
@@ -375,9 +384,9 @@ static void spin_lock_irqsave_sdp_contention(struct srcu_data *sdp, unsigned lon
*/
static void spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
{
- if (spin_trylock_irqsave_rcu_node(ssp, *flags))
+ if (spin_trylock_irqsave_rcu_node(ssp->srcu_sup, *flags))
return;
- spin_lock_irqsave_rcu_node(ssp, *flags);
+ spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags);
spin_lock_irqsave_check_contention(ssp);
}
@@ -394,15 +403,15 @@ static void check_init_srcu_struct(struct srcu_struct *ssp)
unsigned long flags;
/* The smp_load_acquire() pairs with the smp_store_release(). */
- if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq_needed))) /*^^^*/
+ if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed))) /*^^^*/
return; /* Already initialized. */
- spin_lock_irqsave_rcu_node(ssp, flags);
- if (!rcu_seq_state(ssp->srcu_gp_seq_needed)) {
- spin_unlock_irqrestore_rcu_node(ssp, flags);
+ spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags);
+ if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq_needed)) {
+ spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
return;
}
init_srcu_struct_fields(ssp, true);
- spin_unlock_irqrestore_rcu_node(ssp, flags);
+ spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
}
/*
@@ -607,17 +616,18 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp)
unsigned long gpstart;
unsigned long j;
unsigned long jbase = SRCU_INTERVAL;
+ struct srcu_usage *sup = ssp->srcu_sup;
- if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
+ if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp)))
jbase = 0;
- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) {
+ if (rcu_seq_state(READ_ONCE(sup->srcu_gp_seq))) {
j = jiffies - 1;
- gpstart = READ_ONCE(ssp->srcu_gp_start);
+ gpstart = READ_ONCE(sup->srcu_gp_start);
if (time_after(j, gpstart))
jbase += j - gpstart;
if (!jbase) {
- WRITE_ONCE(ssp->srcu_n_exp_nodelay, READ_ONCE(ssp->srcu_n_exp_nodelay) + 1);
- if (READ_ONCE(ssp->srcu_n_exp_nodelay) > srcu_max_nodelay_phase)
+ WRITE_ONCE(sup->srcu_n_exp_nodelay, READ_ONCE(sup->srcu_n_exp_nodelay) + 1);
+ if (READ_ONCE(sup->srcu_n_exp_nodelay) > srcu_max_nodelay_phase)
jbase = 1;
}
}
@@ -634,12 +644,13 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp)
void cleanup_srcu_struct(struct srcu_struct *ssp)
{
int cpu;
+ struct srcu_usage *sup = ssp->srcu_sup;
if (WARN_ON(!srcu_get_delay(ssp)))
return; /* Just leak it! */
if (WARN_ON(srcu_readers_active(ssp)))
return; /* Just leak it! */
- flush_delayed_work(&ssp->work);
+ flush_delayed_work(&sup->work);
for_each_possible_cpu(cpu) {
struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu);
@@ -648,21 +659,23 @@ void cleanup_srcu_struct(struct srcu_struct *ssp)
if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist)))
return; /* Forgot srcu_barrier(), so just leak it! */
}
- if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
- WARN_ON(rcu_seq_current(&ssp->srcu_gp_seq) != ssp->srcu_gp_seq_needed) ||
+ if (WARN_ON(rcu_seq_state(READ_ONCE(sup->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
+ WARN_ON(rcu_seq_current(&sup->srcu_gp_seq) != sup->srcu_gp_seq_needed) ||
WARN_ON(srcu_readers_active(ssp))) {
pr_info("%s: Active srcu_struct %p read state: %d gp state: %lu/%lu\n",
- __func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)),
- rcu_seq_current(&ssp->srcu_gp_seq), ssp->srcu_gp_seq_needed);
+ __func__, ssp, rcu_seq_state(READ_ONCE(sup->srcu_gp_seq)),
+ rcu_seq_current(&sup->srcu_gp_seq), sup->srcu_gp_seq_needed);
return; /* Caller forgot to stop doing call_srcu()? */
}
- if (!ssp->sda_is_static) {
+ kfree(sup->node);
+ sup->node = NULL;
+ sup->srcu_size_state = SRCU_SIZE_SMALL;
+ if (!sup->sda_is_static) {
free_percpu(ssp->sda);
ssp->sda = NULL;
+ kfree(sup);
+ ssp->srcu_sup = NULL;
}
- kfree(ssp->node);
- ssp->node = NULL;
- ssp->srcu_size_state = SRCU_SIZE_SMALL;
}
EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
@@ -760,23 +773,23 @@ static void srcu_gp_start(struct srcu_struct *ssp)
struct srcu_data *sdp;
int state;
- if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
+ if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id());
else
sdp = this_cpu_ptr(ssp->sda);
- lockdep_assert_held(&ACCESS_PRIVATE(ssp, lock));
- WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+ lockdep_assert_held(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
+ WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed));
spin_lock_rcu_node(sdp); /* Interrupts already disabled. */
rcu_segcblist_advance(&sdp->srcu_cblist,
- rcu_seq_current(&ssp->srcu_gp_seq));
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
- rcu_seq_snap(&ssp->srcu_gp_seq));
+ rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq));
spin_unlock_rcu_node(sdp); /* Interrupts remain disabled. */
- WRITE_ONCE(ssp->srcu_gp_start, jiffies);
- WRITE_ONCE(ssp->srcu_n_exp_nodelay, 0);
+ WRITE_ONCE(ssp->srcu_sup->srcu_gp_start, jiffies);
+ WRITE_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay, 0);
smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */
- rcu_seq_start(&ssp->srcu_gp_seq);
- state = rcu_seq_state(ssp->srcu_gp_seq);
+ rcu_seq_start(&ssp->srcu_sup->srcu_gp_seq);
+ state = rcu_seq_state(ssp->srcu_sup->srcu_gp_seq);
WARN_ON_ONCE(state != SRCU_STATE_SCAN1);
}
@@ -849,28 +862,29 @@ static void srcu_gp_end(struct srcu_struct *ssp)
unsigned long sgsne;
struct srcu_node *snp;
int ss_state;
+ struct srcu_usage *sup = ssp->srcu_sup;
/* Prevent more than one additional grace period. */
- mutex_lock(&ssp->srcu_cb_mutex);
+ mutex_lock(&sup->srcu_cb_mutex);
/* End the current grace period. */
- spin_lock_irq_rcu_node(ssp);
- idx = rcu_seq_state(ssp->srcu_gp_seq);
+ spin_lock_irq_rcu_node(sup);
+ idx = rcu_seq_state(sup->srcu_gp_seq);
WARN_ON_ONCE(idx != SRCU_STATE_SCAN2);
- if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
+ if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp)))
cbdelay = 0;
- WRITE_ONCE(ssp->srcu_last_gp_end, ktime_get_mono_fast_ns());
- rcu_seq_end(&ssp->srcu_gp_seq);
- gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
- if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, gpseq))
- WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, gpseq);
- spin_unlock_irq_rcu_node(ssp);
- mutex_unlock(&ssp->srcu_gp_mutex);
+ WRITE_ONCE(sup->srcu_last_gp_end, ktime_get_mono_fast_ns());
+ rcu_seq_end(&sup->srcu_gp_seq);
+ gpseq = rcu_seq_current(&sup->srcu_gp_seq);
+ if (ULONG_CMP_LT(sup->srcu_gp_seq_needed_exp, gpseq))
+ WRITE_ONCE(sup->srcu_gp_seq_needed_exp, gpseq);
+ spin_unlock_irq_rcu_node(sup);
+ mutex_unlock(&sup->srcu_gp_mutex);
/* A new grace period can start at this point. But only one. */
/* Initiate callback invocation as needed. */
- ss_state = smp_load_acquire(&ssp->srcu_size_state);
+ ss_state = smp_load_acquire(&sup->srcu_size_state);
if (ss_state < SRCU_SIZE_WAIT_BARRIER) {
srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, get_boot_cpu_id()),
cbdelay);
@@ -879,7 +893,7 @@ static void srcu_gp_end(struct srcu_struct *ssp)
srcu_for_each_node_breadth_first(ssp, snp) {
spin_lock_irq_rcu_node(snp);
cbs = false;
- last_lvl = snp >= ssp->level[rcu_num_lvls - 1];
+ last_lvl = snp >= sup->level[rcu_num_lvls - 1];
if (last_lvl)
cbs = ss_state < SRCU_SIZE_BIG || snp->srcu_have_cbs[idx] == gpseq;
snp->srcu_have_cbs[idx] = gpseq;
@@ -911,18 +925,18 @@ static void srcu_gp_end(struct srcu_struct *ssp)
}
/* Callback initiation done, allow grace periods after next. */
- mutex_unlock(&ssp->srcu_cb_mutex);
+ mutex_unlock(&sup->srcu_cb_mutex);
/* Start a new grace period if needed. */
- spin_lock_irq_rcu_node(ssp);
- gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
+ spin_lock_irq_rcu_node(sup);
+ gpseq = rcu_seq_current(&sup->srcu_gp_seq);
if (!rcu_seq_state(gpseq) &&
- ULONG_CMP_LT(gpseq, ssp->srcu_gp_seq_needed)) {
+ ULONG_CMP_LT(gpseq, sup->srcu_gp_seq_needed)) {
srcu_gp_start(ssp);
- spin_unlock_irq_rcu_node(ssp);
+ spin_unlock_irq_rcu_node(sup);
srcu_reschedule(ssp, 0);
} else {
- spin_unlock_irq_rcu_node(ssp);
+ spin_unlock_irq_rcu_node(sup);
}
/* Transition to big if needed. */
@@ -930,7 +944,7 @@ static void srcu_gp_end(struct srcu_struct *ssp)
if (ss_state == SRCU_SIZE_ALLOC)
init_srcu_struct_nodes(ssp, GFP_KERNEL);
else
- smp_store_release(&ssp->srcu_size_state, ss_state + 1);
+ smp_store_release(&sup->srcu_size_state, ss_state + 1);
}
}
@@ -950,7 +964,7 @@ static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp
if (snp)
for (; snp != NULL; snp = snp->srcu_parent) {
sgsne = READ_ONCE(snp->srcu_gp_seq_needed_exp);
- if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_gp_seq, s)) ||
+ if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, s)) ||
(!srcu_invl_snp_seq(sgsne) && ULONG_CMP_GE(sgsne, s)))
return;
spin_lock_irqsave_rcu_node(snp, flags);
@@ -963,9 +977,9 @@ static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp
spin_unlock_irqrestore_rcu_node(snp, flags);
}
spin_lock_irqsave_ssp_contention(ssp, &flags);
- if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
- WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, s);
- spin_unlock_irqrestore_rcu_node(ssp, flags);
+ if (ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed_exp, s))
+ WRITE_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp, s);
+ spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
}
/*
@@ -990,9 +1004,10 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
struct srcu_node *snp;
struct srcu_node *snp_leaf;
unsigned long snp_seq;
+ struct srcu_usage *sup = ssp->srcu_sup;
/* Ensure that snp node tree is fully initialized before traversing it */
- if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
+ if (smp_load_acquire(&sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
snp_leaf = NULL;
else
snp_leaf = sdp->mynode;
@@ -1000,7 +1015,7 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
if (snp_leaf)
/* Each pass through the loop does one level of the srcu_node tree. */
for (snp = snp_leaf; snp != NULL; snp = snp->srcu_parent) {
- if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_gp_seq, s)) && snp != snp_leaf)
+ if (WARN_ON_ONCE(rcu_seq_done(&sup->srcu_gp_seq, s)) && snp != snp_leaf)
return; /* GP already done and CBs recorded. */
spin_lock_irqsave_rcu_node(snp, flags);
snp_seq = snp->srcu_have_cbs[idx];
@@ -1027,20 +1042,20 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
/* Top of tree, must ensure the grace period will be started. */
spin_lock_irqsave_ssp_contention(ssp, &flags);
- if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed, s)) {
+ if (ULONG_CMP_LT(sup->srcu_gp_seq_needed, s)) {
/*
* Record need for grace period s. Pair with load
* acquire setting up for initialization.
*/
- smp_store_release(&ssp->srcu_gp_seq_needed, s); /*^^^*/
+ smp_store_release(&sup->srcu_gp_seq_needed, s); /*^^^*/
}
- if (!do_norm && ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
- WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, s);
+ if (!do_norm && ULONG_CMP_LT(sup->srcu_gp_seq_needed_exp, s))
+ WRITE_ONCE(sup->srcu_gp_seq_needed_exp, s);
/* If grace period not already in progress, start it. */
- if (!WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_gp_seq, s)) &&
- rcu_seq_state(ssp->srcu_gp_seq) == SRCU_STATE_IDLE) {
- WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+ if (!WARN_ON_ONCE(rcu_seq_done(&sup->srcu_gp_seq, s)) &&
+ rcu_seq_state(sup->srcu_gp_seq) == SRCU_STATE_IDLE) {
+ WARN_ON_ONCE(ULONG_CMP_GE(sup->srcu_gp_seq, sup->srcu_gp_seq_needed));
srcu_gp_start(ssp);
// And how can that list_add() in the "else" clause
@@ -1049,12 +1064,12 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
// can only be executed during early boot when there is only
// the one boot CPU running with interrupts still disabled.
if (likely(srcu_init_done))
- queue_delayed_work(rcu_gp_wq, &ssp->work,
+ queue_delayed_work(rcu_gp_wq, &sup->work,
!!srcu_get_delay(ssp));
- else if (list_empty(&ssp->work.work.entry))
- list_add(&ssp->work.work.entry, &srcu_boot_list);
+ else if (list_empty(&sup->work.work.entry))
+ list_add(&sup->work.work.entry, &srcu_boot_list);
}
- spin_unlock_irqrestore_rcu_node(ssp, flags);
+ spin_unlock_irqrestore_rcu_node(sup, flags);
}
/*
@@ -1174,18 +1189,18 @@ static bool srcu_might_be_idle(struct srcu_struct *ssp)
/* First, see if enough time has passed since the last GP. */
t = ktime_get_mono_fast_ns();
- tlast = READ_ONCE(ssp->srcu_last_gp_end);
+ tlast = READ_ONCE(ssp->srcu_sup->srcu_last_gp_end);
if (exp_holdoff == 0 ||
time_in_range_open(t, tlast, tlast + exp_holdoff))
return false; /* Too soon after last GP. */
/* Next, check for probable idleness. */
- curseq = rcu_seq_current(&ssp->srcu_gp_seq);
+ curseq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq);
smp_mb(); /* Order ->srcu_gp_seq with ->srcu_gp_seq_needed. */
- if (ULONG_CMP_LT(curseq, READ_ONCE(ssp->srcu_gp_seq_needed)))
+ if (ULONG_CMP_LT(curseq, READ_ONCE(ssp->srcu_sup->srcu_gp_seq_needed)))
return false; /* Grace period in progress, so not idle. */
smp_mb(); /* Order ->srcu_gp_seq with prior access. */
- if (curseq != rcu_seq_current(&ssp->srcu_gp_seq))
+ if (curseq != rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq))
return false; /* GP # changed, so not idle. */
return true; /* With reasonable probability, idle! */
}
@@ -1219,7 +1234,7 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
* sequence number cannot wrap around in the meantime.
*/
idx = __srcu_read_lock_nmisafe(ssp);
- ss_state = smp_load_acquire(&ssp->srcu_size_state);
+ ss_state = smp_load_acquire(&ssp->srcu_sup->srcu_size_state);
if (ss_state < SRCU_SIZE_WAIT_CALL)
sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id());
else
@@ -1228,8 +1243,8 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
if (rhp)
rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp);
rcu_segcblist_advance(&sdp->srcu_cblist,
- rcu_seq_current(&ssp->srcu_gp_seq));
- s = rcu_seq_snap(&ssp->srcu_gp_seq);
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
+ s = rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq);
(void)rcu_segcblist_accelerate(&sdp->srcu_cblist, s);
if (ULONG_CMP_LT(sdp->srcu_gp_seq_needed, s)) {
sdp->srcu_gp_seq_needed = s;
@@ -1327,6 +1342,8 @@ static void __synchronize_srcu(struct srcu_struct *ssp, bool do_norm)
{
struct rcu_synchronize rcu;
+ srcu_lock_sync(&ssp->dep_map);
+
RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) ||
@@ -1440,7 +1457,7 @@ unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp)
// Any prior manipulation of SRCU-protected data must happen
// before the load from ->srcu_gp_seq.
smp_mb();
- return rcu_seq_snap(&ssp->srcu_gp_seq);
+ return rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq);
}
EXPORT_SYMBOL_GPL(get_state_synchronize_srcu);
@@ -1487,7 +1504,7 @@ EXPORT_SYMBOL_GPL(start_poll_synchronize_srcu);
*/
bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie)
{
- if (!rcu_seq_done(&ssp->srcu_gp_seq, cookie))
+ if (!rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, cookie))
return false;
// Ensure that the end of the SRCU grace period happens before
// any subsequent code that the caller might execute.
@@ -1506,8 +1523,8 @@ static void srcu_barrier_cb(struct rcu_head *rhp)
sdp = container_of(rhp, struct srcu_data, srcu_barrier_head);
ssp = sdp->ssp;
- if (atomic_dec_and_test(&ssp->srcu_barrier_cpu_cnt))
- complete(&ssp->srcu_barrier_completion);
+ if (atomic_dec_and_test(&ssp->srcu_sup->srcu_barrier_cpu_cnt))
+ complete(&ssp->srcu_sup->srcu_barrier_completion);
}
/*
@@ -1521,13 +1538,13 @@ static void srcu_barrier_cb(struct rcu_head *rhp)
static void srcu_barrier_one_cpu(struct srcu_struct *ssp, struct srcu_data *sdp)
{
spin_lock_irq_rcu_node(sdp);
- atomic_inc(&ssp->srcu_barrier_cpu_cnt);
+ atomic_inc(&ssp->srcu_sup->srcu_barrier_cpu_cnt);
sdp->srcu_barrier_head.func = srcu_barrier_cb;
debug_rcu_head_queue(&sdp->srcu_barrier_head);
if (!rcu_segcblist_entrain(&sdp->srcu_cblist,
&sdp->srcu_barrier_head)) {
debug_rcu_head_unqueue(&sdp->srcu_barrier_head);
- atomic_dec(&ssp->srcu_barrier_cpu_cnt);
+ atomic_dec(&ssp->srcu_sup->srcu_barrier_cpu_cnt);
}
spin_unlock_irq_rcu_node(sdp);
}
@@ -1540,23 +1557,23 @@ void srcu_barrier(struct srcu_struct *ssp)
{
int cpu;
int idx;
- unsigned long s = rcu_seq_snap(&ssp->srcu_barrier_seq);
+ unsigned long s = rcu_seq_snap(&ssp->srcu_sup->srcu_barrier_seq);
check_init_srcu_struct(ssp);
- mutex_lock(&ssp->srcu_barrier_mutex);
- if (rcu_seq_done(&ssp->srcu_barrier_seq, s)) {
+ mutex_lock(&ssp->srcu_sup->srcu_barrier_mutex);
+ if (rcu_seq_done(&ssp->srcu_sup->srcu_barrier_seq, s)) {
smp_mb(); /* Force ordering following return. */
- mutex_unlock(&ssp->srcu_barrier_mutex);
+ mutex_unlock(&ssp->srcu_sup->srcu_barrier_mutex);
return; /* Someone else did our work for us. */
}
- rcu_seq_start(&ssp->srcu_barrier_seq);
- init_completion(&ssp->srcu_barrier_completion);
+ rcu_seq_start(&ssp->srcu_sup->srcu_barrier_seq);
+ init_completion(&ssp->srcu_sup->srcu_barrier_completion);
/* Initial count prevents reaching zero until all CBs are posted. */
- atomic_set(&ssp->srcu_barrier_cpu_cnt, 1);
+ atomic_set(&ssp->srcu_sup->srcu_barrier_cpu_cnt, 1);
idx = __srcu_read_lock_nmisafe(ssp);
- if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
+ if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, get_boot_cpu_id()));
else
for_each_possible_cpu(cpu)
@@ -1564,12 +1581,12 @@ void srcu_barrier(struct srcu_struct *ssp)
__srcu_read_unlock_nmisafe(ssp, idx);
/* Remove the initial count, at which point reaching zero can happen. */
- if (atomic_dec_and_test(&ssp->srcu_barrier_cpu_cnt))
- complete(&ssp->srcu_barrier_completion);
- wait_for_completion(&ssp->srcu_barrier_completion);
+ if (atomic_dec_and_test(&ssp->srcu_sup->srcu_barrier_cpu_cnt))
+ complete(&ssp->srcu_sup->srcu_barrier_completion);
+ wait_for_completion(&ssp->srcu_sup->srcu_barrier_completion);
- rcu_seq_end(&ssp->srcu_barrier_seq);
- mutex_unlock(&ssp->srcu_barrier_mutex);
+ rcu_seq_end(&ssp->srcu_sup->srcu_barrier_seq);
+ mutex_unlock(&ssp->srcu_sup->srcu_barrier_mutex);
}
EXPORT_SYMBOL_GPL(srcu_barrier);
@@ -1595,7 +1612,7 @@ static void srcu_advance_state(struct srcu_struct *ssp)
{
int idx;
- mutex_lock(&ssp->srcu_gp_mutex);
+ mutex_lock(&ssp->srcu_sup->srcu_gp_mutex);
/*
* Because readers might be delayed for an extended period after
@@ -1607,39 +1624,39 @@ static void srcu_advance_state(struct srcu_struct *ssp)
* The load-acquire ensures that we see the accesses performed
* by the prior grace period.
*/
- idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq)); /* ^^^ */
+ idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq)); /* ^^^ */
if (idx == SRCU_STATE_IDLE) {
- spin_lock_irq_rcu_node(ssp);
- if (ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed)) {
- WARN_ON_ONCE(rcu_seq_state(ssp->srcu_gp_seq));
- spin_unlock_irq_rcu_node(ssp);
- mutex_unlock(&ssp->srcu_gp_mutex);
+ spin_lock_irq_rcu_node(ssp->srcu_sup);
+ if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) {
+ WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq));
+ spin_unlock_irq_rcu_node(ssp->srcu_sup);
+ mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
return;
}
- idx = rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq));
+ idx = rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq));
if (idx == SRCU_STATE_IDLE)
srcu_gp_start(ssp);
- spin_unlock_irq_rcu_node(ssp);
+ spin_unlock_irq_rcu_node(ssp->srcu_sup);
if (idx != SRCU_STATE_IDLE) {
- mutex_unlock(&ssp->srcu_gp_mutex);
+ mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
return; /* Someone else started the grace period. */
}
}
- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) == SRCU_STATE_SCAN1) {
+ if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN1) {
idx = 1 ^ (ssp->srcu_idx & 1);
if (!try_check_zero(ssp, idx, 1)) {
- mutex_unlock(&ssp->srcu_gp_mutex);
+ mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
return; /* readers present, retry later. */
}
srcu_flip(ssp);
- spin_lock_irq_rcu_node(ssp);
- rcu_seq_set_state(&ssp->srcu_gp_seq, SRCU_STATE_SCAN2);
- ssp->srcu_n_exp_nodelay = 0;
- spin_unlock_irq_rcu_node(ssp);
+ spin_lock_irq_rcu_node(ssp->srcu_sup);
+ rcu_seq_set_state(&ssp->srcu_sup->srcu_gp_seq, SRCU_STATE_SCAN2);
+ ssp->srcu_sup->srcu_n_exp_nodelay = 0;
+ spin_unlock_irq_rcu_node(ssp->srcu_sup);
}
- if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) == SRCU_STATE_SCAN2) {
+ if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN2) {
/*
* SRCU read-side critical sections are normally short,
@@ -1647,10 +1664,10 @@ static void srcu_advance_state(struct srcu_struct *ssp)
*/
idx = 1 ^ (ssp->srcu_idx & 1);
if (!try_check_zero(ssp, idx, 2)) {
- mutex_unlock(&ssp->srcu_gp_mutex);
+ mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex);
return; /* readers present, retry later. */
}
- ssp->srcu_n_exp_nodelay = 0;
+ ssp->srcu_sup->srcu_n_exp_nodelay = 0;
srcu_gp_end(ssp); /* Releases ->srcu_gp_mutex. */
}
}
@@ -1676,7 +1693,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
rcu_cblist_init(&ready_cbs);
spin_lock_irq_rcu_node(sdp);
rcu_segcblist_advance(&sdp->srcu_cblist,
- rcu_seq_current(&ssp->srcu_gp_seq));
+ rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
if (sdp->srcu_cblist_invoking ||
!rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) {
spin_unlock_irq_rcu_node(sdp);
@@ -1704,7 +1721,7 @@ static void srcu_invoke_callbacks(struct work_struct *work)
spin_lock_irq_rcu_node(sdp);
rcu_segcblist_add_len(&sdp->srcu_cblist, -len);
(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
- rcu_seq_snap(&ssp->srcu_gp_seq));
+ rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq));
sdp->srcu_cblist_invoking = false;
more = rcu_segcblist_ready_cbs(&sdp->srcu_cblist);
spin_unlock_irq_rcu_node(sdp);
@@ -1720,20 +1737,20 @@ static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay)
{
bool pushgp = true;
- spin_lock_irq_rcu_node(ssp);
- if (ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed)) {
- if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_gp_seq))) {
+ spin_lock_irq_rcu_node(ssp->srcu_sup);
+ if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) {
+ if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq))) {
/* All requests fulfilled, time to go idle. */
pushgp = false;
}
- } else if (!rcu_seq_state(ssp->srcu_gp_seq)) {
+ } else if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq)) {
/* Outstanding request and no GP. Start one. */
srcu_gp_start(ssp);
}
- spin_unlock_irq_rcu_node(ssp);
+ spin_unlock_irq_rcu_node(ssp->srcu_sup);
if (pushgp)
- queue_delayed_work(rcu_gp_wq, &ssp->work, delay);
+ queue_delayed_work(rcu_gp_wq, &ssp->srcu_sup->work, delay);
}
/*
@@ -1744,22 +1761,24 @@ static void process_srcu(struct work_struct *work)
unsigned long curdelay;
unsigned long j;
struct srcu_struct *ssp;
+ struct srcu_usage *sup;
- ssp = container_of(work, struct srcu_struct, work.work);
+ sup = container_of(work, struct srcu_usage, work.work);
+ ssp = sup->srcu_ssp;
srcu_advance_state(ssp);
curdelay = srcu_get_delay(ssp);
if (curdelay) {
- WRITE_ONCE(ssp->reschedule_count, 0);
+ WRITE_ONCE(sup->reschedule_count, 0);
} else {
j = jiffies;
- if (READ_ONCE(ssp->reschedule_jiffies) == j) {
- WRITE_ONCE(ssp->reschedule_count, READ_ONCE(ssp->reschedule_count) + 1);
- if (READ_ONCE(ssp->reschedule_count) > srcu_max_nodelay)
+ if (READ_ONCE(sup->reschedule_jiffies) == j) {
+ WRITE_ONCE(sup->reschedule_count, READ_ONCE(sup->reschedule_count) + 1);
+ if (READ_ONCE(sup->reschedule_count) > srcu_max_nodelay)
curdelay = 1;
} else {
- WRITE_ONCE(ssp->reschedule_count, 1);
- WRITE_ONCE(ssp->reschedule_jiffies, j);
+ WRITE_ONCE(sup->reschedule_count, 1);
+ WRITE_ONCE(sup->reschedule_jiffies, j);
}
}
srcu_reschedule(ssp, curdelay);
@@ -1772,7 +1791,7 @@ void srcutorture_get_gp_data(enum rcutorture_type test_type,
if (test_type != SRCU_FLAVOR)
return;
*flags = 0;
- *gp_seq = rcu_seq_current(&ssp->srcu_gp_seq);
+ *gp_seq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq);
}
EXPORT_SYMBOL_GPL(srcutorture_get_gp_data);
@@ -1794,14 +1813,14 @@ void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf)
int cpu;
int idx;
unsigned long s0 = 0, s1 = 0;
- int ss_state = READ_ONCE(ssp->srcu_size_state);
+ int ss_state = READ_ONCE(ssp->srcu_sup->srcu_size_state);
int ss_state_idx = ss_state;
idx = ssp->srcu_idx & 0x1;
if (ss_state < 0 || ss_state >= ARRAY_SIZE(srcu_size_state_name))
ss_state_idx = ARRAY_SIZE(srcu_size_state_name) - 1;
pr_alert("%s%s Tree SRCU g%ld state %d (%s)",
- tt, tf, rcu_seq_current(&ssp->srcu_gp_seq), ss_state,
+ tt, tf, rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq), ss_state,
srcu_size_state_name[ss_state_idx]);
if (!ssp->sda) {
// Called after cleanup_srcu_struct(), perhaps.
@@ -1858,7 +1877,7 @@ early_initcall(srcu_bootup_announce);
void __init srcu_init(void)
{
- struct srcu_struct *ssp;
+ struct srcu_usage *sup;
/* Decide on srcu_struct-size strategy. */
if (SRCU_SIZING_IS(SRCU_SIZING_AUTO)) {
@@ -1878,12 +1897,13 @@ void __init srcu_init(void)
*/
srcu_init_done = true;
while (!list_empty(&srcu_boot_list)) {
- ssp = list_first_entry(&srcu_boot_list, struct srcu_struct,
+ sup = list_first_entry(&srcu_boot_list, struct srcu_usage,
work.work.entry);
- list_del_init(&ssp->work.work.entry);
- if (SRCU_SIZING_IS(SRCU_SIZING_INIT) && ssp->srcu_size_state == SRCU_SIZE_SMALL)
- ssp->srcu_size_state = SRCU_SIZE_ALLOC;
- queue_work(rcu_gp_wq, &ssp->work.work);
+ list_del_init(&sup->work.work.entry);
+ if (SRCU_SIZING_IS(SRCU_SIZING_INIT) &&
+ sup->srcu_size_state == SRCU_SIZE_SMALL)
+ sup->srcu_size_state = SRCU_SIZE_ALLOC;
+ queue_work(rcu_gp_wq, &sup->work.work);
}
}
@@ -1893,13 +1913,14 @@ void __init srcu_init(void)
static int srcu_module_coming(struct module *mod)
{
int i;
+ struct srcu_struct *ssp;
struct srcu_struct **sspp = mod->srcu_struct_ptrs;
- int ret;
for (i = 0; i < mod->num_srcu_structs; i++) {
- ret = init_srcu_struct(*(sspp++));
- if (WARN_ON_ONCE(ret))
- return ret;
+ ssp = *(sspp++);
+ ssp->sda = alloc_percpu(struct srcu_data);
+ if (WARN_ON_ONCE(!ssp->sda))
+ return -ENOMEM;
}
return 0;
}
@@ -1908,10 +1929,17 @@ static int srcu_module_coming(struct module *mod)
static void srcu_module_going(struct module *mod)
{
int i;
+ struct srcu_struct *ssp;
struct srcu_struct **sspp = mod->srcu_struct_ptrs;
- for (i = 0; i < mod->num_srcu_structs; i++)
- cleanup_srcu_struct(*(sspp++));
+ for (i = 0; i < mod->num_srcu_structs; i++) {
+ ssp = *(sspp++);
+ if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed)) &&
+ !WARN_ON_ONCE(!ssp->srcu_sup->sda_is_static))
+ cleanup_srcu_struct(ssp);
+ if (!WARN_ON(srcu_readers_active(ssp)))
+ free_percpu(ssp->sda);
+ }
}
/* Handle one module, either coming or going. */
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index bfb5e1549f2b..5f4fc8184dd0 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -136,8 +136,16 @@ static struct rcu_tasks rt_name = \
.kname = #rt_name, \
}
+#ifdef CONFIG_TASKS_RCU
/* Track exiting tasks in order to allow them to be waited for. */
DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu);
+#endif
+
+#ifdef CONFIG_TASKS_RCU
+/* Report delay in synchronize_srcu() completion in rcu_tasks_postscan(). */
+static void tasks_rcu_exit_srcu_stall(struct timer_list *unused);
+static DEFINE_TIMER(tasks_rcu_exit_srcu_stall_timer, tasks_rcu_exit_srcu_stall);
+#endif
/* Avoid IPIing CPUs early in the grace period. */
#define RCU_TASK_IPI_DELAY (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) ? HZ / 2 : 0)
@@ -830,6 +838,13 @@ static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop)
/* Processing between scanning taskslist and draining the holdout list. */
static void rcu_tasks_postscan(struct list_head *hop)
{
+ int rtsi = READ_ONCE(rcu_task_stall_info);
+
+ if (!IS_ENABLED(CONFIG_TINY_RCU)) {
+ tasks_rcu_exit_srcu_stall_timer.expires = jiffies + rtsi;
+ add_timer(&tasks_rcu_exit_srcu_stall_timer);
+ }
+
/*
* Exiting tasks may escape the tasklist scan. Those are vulnerable
* until their final schedule() with TASK_DEAD state. To cope with
@@ -848,6 +863,9 @@ static void rcu_tasks_postscan(struct list_head *hop)
* call to synchronize_rcu().
*/
synchronize_srcu(&tasks_rcu_exit_srcu);
+
+ if (!IS_ENABLED(CONFIG_TINY_RCU))
+ del_timer_sync(&tasks_rcu_exit_srcu_stall_timer);
}
/* See if tasks are still holding out, complain if so. */
@@ -923,6 +941,21 @@ static void rcu_tasks_postgp(struct rcu_tasks *rtp)
void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func);
DEFINE_RCU_TASKS(rcu_tasks, rcu_tasks_wait_gp, call_rcu_tasks, "RCU Tasks");
+static void tasks_rcu_exit_srcu_stall(struct timer_list *unused)
+{
+#ifndef CONFIG_TINY_RCU
+ int rtsi;
+
+ rtsi = READ_ONCE(rcu_task_stall_info);
+ pr_info("%s: %s grace period number %lu (since boot) gp_state: %s is %lu jiffies old.\n",
+ __func__, rcu_tasks.kname, rcu_tasks.tasks_gp_seq,
+ tasks_gp_state_getname(&rcu_tasks), jiffies - rcu_tasks.gp_jiffies);
+ pr_info("Please check any exiting tasks stuck between calls to exit_tasks_rcu_start() and exit_tasks_rcu_finish()\n");
+ tasks_rcu_exit_srcu_stall_timer.expires = jiffies + rtsi;
+ add_timer(&tasks_rcu_exit_srcu_stall_timer);
+#endif // #ifndef CONFIG_TINY_RCU
+}
+
/**
* call_rcu_tasks() - Queue an RCU for invocation task-based grace period
* @rhp: structure to be used for queueing the RCU updates.
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 06cc6a6ad819..734c252c1e80 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -640,6 +640,7 @@ void __rcu_irq_enter_check_tick(void)
}
raw_spin_unlock_rcu_node(rdp->mynode);
}
+NOKPROBE_SYMBOL(__rcu_irq_enter_check_tick);
#endif /* CONFIG_NO_HZ_FULL */
/*
@@ -1955,7 +1956,6 @@ rcu_report_qs_rdp(struct rcu_data *rdp)
{
unsigned long flags;
unsigned long mask;
- bool needwake = false;
bool needacc = false;
struct rcu_node *rnp;
@@ -1987,7 +1987,12 @@ rcu_report_qs_rdp(struct rcu_data *rdp)
* NOCB kthreads have their own way to deal with that...
*/
if (!rcu_rdp_is_offloaded(rdp)) {
- needwake = rcu_accelerate_cbs(rnp, rdp);
+ /*
+ * The current GP has not yet ended, so it
+ * should not be possible for rcu_accelerate_cbs()
+ * to return true. So complain, but don't awaken.
+ */
+ WARN_ON_ONCE(rcu_accelerate_cbs(rnp, rdp));
} else if (!rcu_segcblist_completely_offloaded(&rdp->cblist)) {
/*
* ...but NOCB kthreads may miss or delay callbacks acceleration
@@ -1999,8 +2004,6 @@ rcu_report_qs_rdp(struct rcu_data *rdp)
rcu_disable_urgency_upon_qs(rdp);
rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
/* ^^^ Released rnp->lock */
- if (needwake)
- rcu_gp_kthread_wake();
if (needacc) {
rcu_nocb_lock_irqsave(rdp, flags);
@@ -4942,9 +4945,8 @@ void __init rcu_init(void)
else
qovld_calc = qovld;
- // Kick-start any polled grace periods that started early.
- if (!(per_cpu_ptr(&rcu_data, cpu)->mynode->exp_seq_poll_rq & 0x1))
- (void)start_poll_synchronize_rcu_expedited();
+ // Kick-start in case any polled grace periods started early.
+ (void)start_poll_synchronize_rcu_expedited();
rcu_test_sync_prims();
}
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 249c2967d9e6..3b7abb58157d 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -594,6 +594,7 @@ static void synchronize_rcu_expedited_wait(void)
struct rcu_data *rdp;
struct rcu_node *rnp;
struct rcu_node *rnp_root = rcu_get_root();
+ unsigned long flags;
trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("startwait"));
jiffies_stall = rcu_exp_jiffies_till_stall_check();
@@ -602,17 +603,17 @@ static void synchronize_rcu_expedited_wait(void)
if (synchronize_rcu_expedited_wait_once(1))
return;
rcu_for_each_leaf_node(rnp) {
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
mask = READ_ONCE(rnp->expmask);
for_each_leaf_node_cpu_mask(rnp, cpu, mask) {
rdp = per_cpu_ptr(&rcu_data, cpu);
if (rdp->rcu_forced_tick_exp)
continue;
rdp->rcu_forced_tick_exp = true;
- preempt_disable();
if (cpu_online(cpu))
tick_dep_set_cpu(cpu, TICK_DEP_BIT_RCU_EXP);
- preempt_enable();
}
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
j = READ_ONCE(jiffies_till_first_fqs);
if (synchronize_rcu_expedited_wait_once(j + HZ))
@@ -802,9 +803,11 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp)
int ndetected = 0;
struct task_struct *t;
- if (!READ_ONCE(rnp->exp_tasks))
- return 0;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ if (!rnp->exp_tasks) {
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ return 0;
+ }
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry);
list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
@@ -1065,9 +1068,10 @@ unsigned long start_poll_synchronize_rcu_expedited(void)
if (rcu_init_invoked())
raw_spin_lock_irqsave(&rnp->exp_poll_lock, flags);
if (!poll_state_synchronize_rcu(s)) {
- rnp->exp_seq_poll_rq = s;
- if (rcu_init_invoked())
+ if (rcu_init_invoked()) {
+ rnp->exp_seq_poll_rq = s;
queue_work(rcu_gp_wq, &rnp->exp_poll_wq);
+ }
}
if (rcu_init_invoked())
raw_spin_unlock_irqrestore(&rnp->exp_poll_lock, flags);
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 9e1c8caec5ce..f2280616f9d5 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -1312,6 +1312,7 @@ int rcu_nocb_cpu_offload(int cpu)
}
EXPORT_SYMBOL_GPL(rcu_nocb_cpu_offload);
+#ifdef CONFIG_RCU_LAZY
static unsigned long
lazy_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
{
@@ -1360,6 +1361,7 @@ static struct shrinker lazy_rcu_shrinker = {
.batch = 0,
.seeks = DEFAULT_SEEKS,
};
+#endif // #ifdef CONFIG_RCU_LAZY
void __init rcu_init_nohz(void)
{
@@ -1391,8 +1393,10 @@ void __init rcu_init_nohz(void)
if (!rcu_state.nocb_is_setup)
return;
+#ifdef CONFIG_RCU_LAZY
if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy"))
pr_err("Failed to register lazy_rcu shrinker!\n");
+#endif // #ifdef CONFIG_RCU_LAZY
if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 14:27:20 +0100