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rhashtable-test: retry insert operations 

After adding cond_resched() calls to threadfunc(), a surprisingly high
rate of insert failures occurred probably due to table resizes getting a
better chance to run in background. To not soften up the remaining
tests, retry inserts until they either succeed or fail permanently.

Also change the non-threaded test to retry insert operations, too.

Suggested-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Phil Sutter 2015-11-20 18:17:18 +01:00 committed by David S. Miller
parent cd5b318daf
commit 9e9089e5a2
1 changed files with 29 additions and 24 deletions
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53
lib/test_rhashtable.c
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@ -76,6 +76,20 @@ static struct rhashtable_params test_rht_params = {
static struct semaphore prestart_sem;
static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);
static int insert_retry(struct rhashtable *ht, struct rhash_head *obj,
const struct rhashtable_params params)
{
int err, retries = -1;
do {
retries++;
cond_resched();
err = rhashtable_insert_fast(ht, obj, params);
} while (err == -EBUSY);
return err ? : retries;
}
static int __init test_rht_lookup(struct rhashtable *ht)
{
unsigned int i;
@ -157,7 +171,7 @@ static s64 __init test_rhashtable(struct rhashtable *ht)
{
struct test_obj *obj;
int err;
unsigned int i, insert_fails = 0;
unsigned int i, insert_retries = 0;
s64 start, end;
/*
@ -170,22 +184,16 @@ static s64 __init test_rhashtable(struct rhashtable *ht)
struct test_obj *obj = &array[i];
obj->value = i * 2;
err = rhashtable_insert_fast(ht, &obj->node, test_rht_params);
if (err == -ENOMEM || err == -EBUSY) {
/* Mark failed inserts but continue */
obj->value = TEST_INSERT_FAIL;
insert_fails++;
} else if (err) {
err = insert_retry(ht, &obj->node, test_rht_params);
if (err > 0)
insert_retries += err;
else if (err)
return err;
}
cond_resched();
}
if (insert_fails)
pr_info(" %u insertions failed due to memory pressure\n",
insert_fails);
if (insert_retries)
pr_info(" %u insertions retried due to memory pressure\n",
insert_retries);
test_bucket_stats(ht);
rcu_read_lock();
@ -244,7 +252,7 @@ static int thread_lookup_test(struct thread_data *tdata)
static int threadfunc(void *data)
{
int i, step, err = 0, insert_fails = 0;
int i, step, err = 0, insert_retries = 0;
struct thread_data *tdata = data;
up(&prestart_sem);
@ -253,21 +261,18 @@ static int threadfunc(void *data)
for (i = 0; i < entries; i++) {
tdata->objs[i].value = (tdata->id << 16) | i;
cond_resched();
err = rhashtable_insert_fast(&ht, &tdata->objs[i].node,
test_rht_params);
if (err == -ENOMEM || err == -EBUSY) {
tdata->objs[i].value = TEST_INSERT_FAIL;
insert_fails++;
err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
if (err > 0) {
insert_retries += err;
} else if (err) {
pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
tdata->id);
goto out;
}
}
if (insert_fails)
pr_info(" thread[%d]: %d insert failures\n",
tdata->id, insert_fails);
if (insert_retries)
pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
tdata->id, insert_retries);
err = thread_lookup_test(tdata);
if (err) {