github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-04 20:46:48 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

rcutorture: Add writer-side tests of polling grace-period API

Browse Source 
This commit adds writer-side testing of the polling grace-period API.
One test verifies that the polling API sees a grace period caused by
some other mechanism.  Another test verifies that using the polling API
to wait for a grace period does not result in too-short grace periods.
A third test verifies that the polling API does not report
completion within a read-side critical section.  A fourth and final
test verifies that the polling API does report completion given an
intervening grace period.

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>
This commit is contained in:
Paul E. McKenney 2020-11-13 20:43:59 -08:00
parent fd56f64b4e
commit 0fd0548db1
1 changed files with 72 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
kernel/rcu/rcutorture.c
View File

@ -85,6 +85,7 @@ torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
torture_param(bool, gp_normal, false,
"Use normal (non-expedited) GP wait primitives");
torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
@ -183,9 +184,11 @@ static int rcu_torture_writer_state;
#define RTWS_EXP_SYNC 4
#define RTWS_COND_GET 5
#define RTWS_COND_SYNC 6
#define RTWS_SYNC 7
#define RTWS_STUTTER 8
#define RTWS_STOPPING 9
#define RTWS_POLL_GET 7
#define RTWS_POLL_WAIT 8
#define RTWS_SYNC 9
#define RTWS_STUTTER 10
#define RTWS_STOPPING 11
static const char * const rcu_torture_writer_state_names[] = {
"RTWS_FIXED_DELAY",
"RTWS_DELAY",
@ -194,6 +197,8 @@ static const char * const rcu_torture_writer_state_names[] = {
"RTWS_EXP_SYNC",
"RTWS_COND_GET",
"RTWS_COND_SYNC",
"RTWS_POLL_GET",
"RTWS_POLL_WAIT",
"RTWS_SYNC",
"RTWS_STUTTER",
"RTWS_STOPPING",
@ -312,6 +317,8 @@ struct rcu_torture_ops {
void (*sync)(void);
void (*exp_sync)(void);
unsigned long (*get_gp_state)(void);
unsigned long (*start_gp_poll)(void);
bool (*poll_gp_state)(unsigned long oldstate);
void (*cond_sync)(unsigned long oldstate);
call_rcu_func_t call;
void (*cb_barrier)(void);
@ -570,6 +577,21 @@ static void srcu_torture_synchronize(void)
synchronize_srcu(srcu_ctlp);
}
static unsigned long srcu_torture_get_gp_state(void)
{
return get_state_synchronize_srcu(srcu_ctlp);
}
static unsigned long srcu_torture_start_gp_poll(void)
{
return start_poll_synchronize_srcu(srcu_ctlp);
}
static bool srcu_torture_poll_gp_state(unsigned long oldstate)
{
return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
}
static void srcu_torture_call(struct rcu_head *head,
rcu_callback_t func)
{
@ -601,6 +623,9 @@ static struct rcu_torture_ops srcu_ops = {
.deferred_free = srcu_torture_deferred_free,
.sync = srcu_torture_synchronize,
.exp_sync = srcu_torture_synchronize_expedited,
.get_gp_state = srcu_torture_get_gp_state,
.start_gp_poll = srcu_torture_start_gp_poll,
.poll_gp_state = srcu_torture_poll_gp_state,
.call = srcu_torture_call,
.cb_barrier = srcu_torture_barrier,
.stats = srcu_torture_stats,
@ -1027,18 +1052,20 @@ static int
rcu_torture_writer(void *arg)
{
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_sync1 = gp_sync;
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_SYNC };
RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC };
int nsynctypes = 0;
VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
@ -1048,8 +1075,8 @@ rcu_torture_writer(void *arg)
torture_type, cur_ops->name);
/* Initialize synctype[] array. If none set, take default. */
if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1)
gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true;
if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
synctype[nsynctypes++] = RTWS_COND_GET;
pr_info("%s: Testing conditional GPs.\n", __func__);
@ -1068,6 +1095,12 @@ rcu_torture_writer(void *arg)
} else if (gp_normal && !cur_ops->deferred_free) {
pr_alert("%s: gp_normal without primitives.\n", __func__);
}
if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
synctype[nsynctypes++] = RTWS_POLL_GET;
pr_info("%s: Testing polling GPs.\n", __func__);
} else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
pr_alert("%s: gp_poll without primitives.\n", __func__);
}
if (gp_sync1 && cur_ops->sync) {
synctype[nsynctypes++] = RTWS_SYNC;
pr_info("%s: Testing normal GPs.\n", __func__);
@ -1107,6 +1140,18 @@ rcu_torture_writer(void *arg)
atomic_inc(&rcu_torture_wcount[i]);
WRITE_ONCE(old_rp->rtort_pipe_count,
old_rp->rtort_pipe_count + 1);
if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
idx = cur_ops->readlock();
cookie = cur_ops->get_gp_state();
WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE &&
cur_ops->poll_gp_state(cookie),
"%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
__func__,
rcu_torture_writer_state_getname(),
rcu_torture_writer_state,
cookie, cur_ops->get_gp_state());
cur_ops->readunlock(idx);
}
switch (synctype[torture_random(&rand) % nsynctypes]) {
case RTWS_DEF_FREE:
rcu_torture_writer_state = RTWS_DEF_FREE;
@ -1128,6 +1173,18 @@ rcu_torture_writer(void *arg)
cur_ops->cond_sync(gp_snap);
rcu_torture_pipe_update(old_rp);
break;
case RTWS_POLL_GET:
rcu_torture_writer_state = RTWS_POLL_GET;
gp_snap = cur_ops->start_gp_poll();
rcu_torture_writer_state = RTWS_POLL_WAIT;
while (!cur_ops->poll_gp_state(gp_snap)) {
i = torture_random(&rand) % 16;
if (i != 0)
schedule_timeout_interruptible(i);
udelay(torture_random(&rand) % 1000);
}
rcu_torture_pipe_update(old_rp);
break;
case RTWS_SYNC:
rcu_torture_writer_state = RTWS_SYNC;
cur_ops->sync();
@ -1137,6 +1194,14 @@ rcu_torture_writer(void *arg)
WARN_ON_ONCE(1);
break;
}
if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE &&
!cur_ops->poll_gp_state(cookie),
"%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
__func__,
rcu_torture_writer_state_getname(),
rcu_torture_writer_state,
cookie, cur_ops->get_gp_state());
}
WRITE_ONCE(rcu_torture_current_version,
rcu_torture_current_version + 1);