2019-11-07 19:15:53

by Laura Abbott

Subject: [PATCH] lib/test_meminit.c: Add bulk alloc/free tests

kmem_cache_alloc_bulk/kmem_cache_free_bulk are used to
make multiple allocations of the same size to avoid the
overhead of multiple kmalloc/kfree calls. Extend the kmem_cache
tests to make some calls to these APIs.

Signed-off-by: Laura Abbott <[email protected]>
---
lib/test_meminit.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/test_meminit.c b/lib/test_meminit.c
index 9729f271d150..20f330948b92 100644
--- a/lib/test_meminit.c
+++ b/lib/test_meminit.c
@@ -183,6 +183,9 @@ static bool __init check_buf(void *buf, int size, bool want_ctor,
return fail;
}

+#define BULK_SIZE 100
+static void *bulk_array[BULK_SIZE];
+
/*
* Test kmem_cache with given parameters:
* want_ctor - use a constructor;
@@ -203,9 +206,24 @@ static int __init do_kmem_cache_size(size_t size, bool want_ctor,
want_rcu ? SLAB_TYPESAFE_BY_RCU : 0,
want_ctor ? test_ctor : NULL);
for (iter = 0; iter < 10; iter++) {
+ /* Do a test of bulk allocations */
+ if (!want_rcu && !want_ctor) {
+ int ret;
+
+ ret = kmem_cache_alloc_bulk(c, alloc_mask, BULK_SIZE, bulk_array);
+ if (!ret) {
+ fail = true;
+ } else {
+ int i;
+ for (i = 0; i < ret; i++)
+ fail |= check_buf(bulk_array[i], size, want_ctor, want_rcu, want_zero);
+ kmem_cache_free_bulk(c, ret, bulk_array);
+ }
+ }
+
buf = kmem_cache_alloc(c, alloc_mask);
/* Check that buf is zeroed, if it must be. */
- fail = check_buf(buf, size, want_ctor, want_rcu, want_zero);
+ fail |= check_buf(buf, size, want_ctor, want_rcu, want_zero);
fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0);

if (!want_rcu) {
--
2.21.0

2019-11-07 21:20:54

by Kees Cook

Subject: Re: [PATCH] lib/test_meminit.c: Add bulk alloc/free tests

On Thu, Nov 07, 2019 at 02:14:47PM -0500, Laura Abbott wrote:
>
> kmem_cache_alloc_bulk/kmem_cache_free_bulk are used to
> make multiple allocations of the same size to avoid the
> overhead of multiple kmalloc/kfree calls. Extend the kmem_cache
> tests to make some calls to these APIs.
>
> Signed-off-by: Laura Abbott <[email protected]>

Thanks! Andrew, can you add this to -mm please?

Reviewed-by: Kees Cook <[email protected]>

-Kees

> ---
> lib/test_meminit.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/lib/test_meminit.c b/lib/test_meminit.c
> index 9729f271d150..20f330948b92 100644
> --- a/lib/test_meminit.c
> +++ b/lib/test_meminit.c
> @@ -183,6 +183,9 @@ static bool __init check_buf(void *buf, int size, bool want_ctor,
> return fail;
> }
>
> +#define BULK_SIZE 100
> +static void *bulk_array[BULK_SIZE];
> +
> /*
> * Test kmem_cache with given parameters:
> * want_ctor - use a constructor;
> @@ -203,9 +206,24 @@ static int __init do_kmem_cache_size(size_t size, bool want_ctor,
> want_rcu ? SLAB_TYPESAFE_BY_RCU : 0,
> want_ctor ? test_ctor : NULL);
> for (iter = 0; iter < 10; iter++) {
> + /* Do a test of bulk allocations */
> + if (!want_rcu && !want_ctor) {
> + int ret;
> +
> + ret = kmem_cache_alloc_bulk(c, alloc_mask, BULK_SIZE, bulk_array);
> + if (!ret) {
> + fail = true;
> + } else {
> + int i;
> + for (i = 0; i < ret; i++)
> + fail |= check_buf(bulk_array[i], size, want_ctor, want_rcu, want_zero);
> + kmem_cache_free_bulk(c, ret, bulk_array);
> + }
> + }
> +
> buf = kmem_cache_alloc(c, alloc_mask);
> /* Check that buf is zeroed, if it must be. */
> - fail = check_buf(buf, size, want_ctor, want_rcu, want_zero);
> + fail |= check_buf(buf, size, want_ctor, want_rcu, want_zero);
> fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0);
>
> if (!want_rcu) {
> --
> 2.21.0
>

--
Kees Cook