On Mon, Jun 15, 2015 at 05:52:56PM +0200, Jesper Dangaard Brouer wrote:
> This implements SLUB specific kmem_cache_free_bulk(). SLUB allocator
> now both have bulk alloc and free implemented.
>
> Play nice and reenable local IRQs while calling slowpath.
>
> Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
> ---
> mm/slub.c | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 98d0e6f73ec1..cc4f870677bb 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2752,7 +2752,37 @@ EXPORT_SYMBOL(kmem_cache_free);
>
> void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
> {
> - __kmem_cache_free_bulk(s, size, p);
> + struct kmem_cache_cpu *c;
> + struct page *page;
> + int i;
> +
> + local_irq_disable();
> + c = this_cpu_ptr(s->cpu_slab);
> +
> + for (i = 0; i < size; i++) {
> + void *object = p[i];
> +
> + if (unlikely(!object))
> + continue; // HOW ABOUT BUG_ON()???
> +
> + page = virt_to_head_page(object);
> + BUG_ON(s != page->slab_cache); /* Check if valid slab page */
> +
> + if (c->page == page) {
> + /* Fastpath: local CPU free */
> + set_freepointer(s, object, c->freelist);
> + c->freelist = object;
> + } else {
> + c->tid = next_tid(c->tid);
> + local_irq_enable();
> + /* Slowpath: overhead locked cmpxchg_double_slab */
> + __slab_free(s, page, object, _RET_IP_);
> + local_irq_disable();
> + c = this_cpu_ptr(s->cpu_slab);
SLUB free path doesn't need to irq management in many cases although
it uses cmpxchg_doule_slab. Is this really better than just calling
__kmem_cache_free_bulk()?
Thanks.
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