2020-03-06 01:17:24

by Joel Fernandes

Subject: [PATCH rcu-dev 1/2] rcuperf: Add ability to increase object allocation size

This allows us to increase memory pressure dynamically using a new
rcuperf boot command line parameter called 'rcumult'.

Signed-off-by: Joel Fernandes (Google) <[email protected]>

---
kernel/rcu/rcuperf.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
index a4a8d097d84d9..16dd1e6b7c09f 100644
--- a/kernel/rcu/rcuperf.c
+++ b/kernel/rcu/rcuperf.c
@@ -88,6 +88,7 @@ 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(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate.");

static char *perf_type = "rcu";
module_param(perf_type, charp, 0444);
@@ -635,7 +636,7 @@ kfree_perf_thread(void *arg)
}

for (i = 0; i < kfree_alloc_num; i++) {
- alloc_ptr = kmalloc(sizeof(struct kfree_obj), GFP_KERNEL);
+ alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
if (!alloc_ptr)
return -ENOMEM;

@@ -722,6 +723,8 @@ kfree_perf_init(void)
schedule_timeout_uninterruptible(1);
}

+ pr_alert("kfree object size=%lu\n", kfree_mult * sizeof(struct kfree_obj));
+
kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
GFP_KERNEL);
if (kfree_reader_tasks == NULL) {
--
2.25.0.265.gbab2e86ba0-goog

2020-03-06 01:37:42

by Paul E. McKenney

Subject: Re: [PATCH rcu-dev 1/2] rcuperf: Add ability to increase object allocation size

On Thu, Mar 05, 2020 at 08:16:25PM -0500, Joel Fernandes (Google) wrote:
> This allows us to increase memory pressure dynamically using a new
> rcuperf boot command line parameter called 'rcumult'.
>
> Signed-off-by: Joel Fernandes (Google) <[email protected]>

Looks plausible to me at a very quick first glance. Uladzislau, thoughts?

Thanx, Paul

> ---
> kernel/rcu/rcuperf.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
> index a4a8d097d84d9..16dd1e6b7c09f 100644
> --- a/kernel/rcu/rcuperf.c
> +++ b/kernel/rcu/rcuperf.c
> @@ -88,6 +88,7 @@ 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(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate.");
>
> static char *perf_type = "rcu";
> module_param(perf_type, charp, 0444);
> @@ -635,7 +636,7 @@ kfree_perf_thread(void *arg)
> }
>
> for (i = 0; i < kfree_alloc_num; i++) {
> - alloc_ptr = kmalloc(sizeof(struct kfree_obj), GFP_KERNEL);
> + alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
> if (!alloc_ptr)
> return -ENOMEM;
>
> @@ -722,6 +723,8 @@ kfree_perf_init(void)
> schedule_timeout_uninterruptible(1);
> }
>
> + pr_alert("kfree object size=%lu\n", kfree_mult * sizeof(struct kfree_obj));
> +
> kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
> GFP_KERNEL);
> if (kfree_reader_tasks == NULL) {
> --
> 2.25.0.265.gbab2e86ba0-goog
>