Hello, Joel.
> This patch varies the allocated size of objects to be more realistic in
> comparison to production workloads.
>
> Cc: urezki@xxxxxxxxx
> Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
>
> ---
> kernel/rcu/rcuperf.c | 48 +++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 41 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
> index da94b89cd531..1fd0cc72022e 100644
> --- a/kernel/rcu/rcuperf.c
> +++ b/kernel/rcu/rcuperf.c
> @@ -87,6 +87,7 @@ torture_param(bool, shutdown, RCUPERF_SHUTDOWN,
> torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
> torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
> torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() perf test?");
> +torture_param(bool, kfree_vary_obj_size, 0, "Vary the kfree_rcu object size");
>
> static char *perf_type = "rcu";
> module_param(perf_type, charp, 0444);
> @@ -599,17 +600,29 @@ static int kfree_nrealthreads;
> static atomic_t n_kfree_perf_thread_started;
> static atomic_t n_kfree_perf_thread_ended;
>
> -struct kfree_obj {
> - char kfree_obj[8];
> - struct rcu_head rh;
> -};
> +/*
> + * Define a kfree_obj with size as the @size parameter + the size of rcu_head
> + * (rcu_head is 16 bytes on 64-bit arch).
> + */
> +#define DEFINE_KFREE_OBJ(size) \
> +struct kfree_obj_ ## size { \
> + char kfree_obj[size]; \
> + struct rcu_head rh; \
> +}
> +
> +/* This should goto the right sized slabs on both 32-bit and 64-bit arch */
> +DEFINE_KFREE_OBJ(16); // goes on kmalloc-32 slab
> +DEFINE_KFREE_OBJ(32); // goes on kmalloc-64 slab
> +DEFINE_KFREE_OBJ(64); // goes on kmalloc-96 slab
> +DEFINE_KFREE_OBJ(96); // goes on kmalloc-128 slab
>
> static int
> kfree_perf_thread(void *arg)
> {
> int i, loop = 0;
> long me = (long)arg;
> - struct kfree_obj *alloc_ptr;
> + void *alloc_ptr;
> +
> u64 start_time, end_time;
>
> VERBOSE_PERFOUT_STRING("kfree_perf_thread task started");
> @@ -627,11 +640,32 @@ kfree_perf_thread(void *arg)
>
> do {
> for (i = 0; i < kfree_alloc_num; i++) {
> - alloc_ptr = kmalloc(sizeof(struct kfree_obj), GFP_KERNEL);
> + int kfree_type = i % 4;
> +
> + // Allocate only kfree_obj_16 if rcuperf.kfree_vary_obj_size not passed.
> + if (!kfree_vary_obj_size)
> + kfree_type = 0;
> +
> + if (kfree_type == 0)
> + alloc_ptr = kmalloc(sizeof(struct kfree_obj_16), GFP_KERNEL);
> + else if (kfree_type == 1)
> + alloc_ptr = kmalloc(sizeof(struct kfree_obj_32), GFP_KERNEL);
> + else if (kfree_type == 2)
> + alloc_ptr = kmalloc(sizeof(struct kfree_obj_64), GFP_KERNEL);
> + else
> + alloc_ptr = kmalloc(sizeof(struct kfree_obj_96), GFP_KERNEL);
> +
> if (!alloc_ptr)
> return -ENOMEM;
>
> - kfree_rcu(alloc_ptr, rh);
> + if (kfree_type == 0)
> + kfree_rcu((struct kfree_obj_16 *)alloc_ptr, rh);
> + else if (kfree_type == 1)
> + kfree_rcu((struct kfree_obj_32 *)alloc_ptr, rh);
> + else if (kfree_type == 2)
> + kfree_rcu((struct kfree_obj_64 *)alloc_ptr, rh);
> + else
> + kfree_rcu((struct kfree_obj_96 *)alloc_ptr, rh);
> }
>
> cond_resched();
> --
> 2.25.0.rc1.283.g88dfdc4193-goog
>
Good point and patch!
Tested-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
--
Vlad Rezki
