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rhashtable-test: allow to retry even if -ENOMEM was returned
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This is rather a hack to expose the current issue with rhashtable to
under high pressure sometimes return -ENOMEM even though system memory
is not exhausted and a consecutive insert may succeed.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Phil Sutter authored and David S. Miller committed Nov 23, 2015
1 parent 95e435a commit d662e03
Showing 1 changed file with 13 additions and 1 deletion.
14 changes: 13 additions & 1 deletion lib/test_rhashtable.c
Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,10 @@ static int tcount = 10;
module_param(tcount, int, 0);
MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");

static bool enomem_retry = false;
module_param(enomem_retry, bool, 0);
MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");

struct test_obj {
int value;
struct rhash_head node;
Expand Down Expand Up @@ -79,14 +83,22 @@ 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;
int err, retries = -1, enomem_retries = 0;

do {
retries++;
cond_resched();
err = rhashtable_insert_fast(ht, obj, params);
if (err == -ENOMEM && enomem_retry) {
enomem_retries++;
err = -EBUSY;
}
} while (err == -EBUSY);

if (enomem_retries)
pr_info(" %u insertions retried after -ENOMEM\n",
enomem_retries);

return err ? : retries;
}

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