On Sun, Apr 07, 2024 at 09:08:48PM +0800, Yunsheng Lin wrote:
> Basing on the lib/objpool.c, change it to something like a
> ptrpool, so that we can utilize that to test the correctness
> and performance of the page_frag.
>
> The testing is done by ensuring that the fragments allocated
> from a frag_frag_cache instance is pushed into a ptrpool
> instance in a kthread binded to the first cpu, and a kthread
> binded to the current node will pop the fragmemt from the
> ptrpool and call page_frag_alloc_va() to free the fragmemt.
>
> We may refactor out the common part between objpool and ptrpool
> if this ptrpool thing turns out to be helpful for other place.
>
> Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
...
> diff --git a/mm/page_frag_test.c b/mm/page_frag_test.c
...
> +/* allocate and initialize percpu slots */
> +static int objpool_init_percpu_slots(struct objpool_head *pool,
> + int nr_objs, gfp_t gfp)
> +{
> + int i;
> +
> + for (i = 0; i < pool->nr_cpus; i++) {
> + struct objpool_slot *slot;
> + int size;
> +
> + /* skip the cpu node which could never be present */
> + if (!cpu_possible(i))
> + continue;
> +
> + size = struct_size(slot, entries, pool->capacity);
> +
> + /*
> + * here we allocate percpu-slot & objs together in a single
> + * allocation to make it more compact, taking advantage of
> + * warm caches and TLB hits. in default vmalloc is used to
> + * reduce the pressure of kernel slab system. as we know,
> + * mimimal size of vmalloc is one page since vmalloc would
nit: minimal
> + * always align the requested size to page size
> + */
> + if (gfp & GFP_ATOMIC)
> + slot = kmalloc_node(size, gfp, cpu_to_node(i));
> + else
> + slot = __vmalloc_node(size, sizeof(void *), gfp,
> + cpu_to_node(i),
> + __builtin_return_address(0));
> + if (!slot)
> + return -ENOMEM;
> +
> + memset(slot, 0, size);
> + pool->cpu_slots[i] = slot;
> +
> + objpool_init_percpu_slot(pool, slot);
> + }
> +
> + return 0;
> +}
...
> +static struct objpool_head ptr_pool;
> +static int nr_objs = 512;
> +static int nr_test = 5120000;
> +static atomic_t nthreads;
> +static struct completion wait;
> +struct page_frag_cache test_frag;
nit: Is test_frag used outside of this file?
If not, should it be static?
...
