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Commit 9e9089e5 authored by Phil Sutter's avatar Phil Sutter Committed by David S. Miller
Browse files

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: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarPhil Sutter <phil@nwl.cc>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cd5b318d

lib/test_rhashtable.c

+29 −24
Original line number Diff line number Diff line
@@ -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) {