On Fri, 10 Jul 2015 12:07:13 -0000
Thomas Gleixner <[email protected]> wrote:
> /*
> * Slab allocation and freeing
> */
> @@ -1336,6 +1347,8 @@ static struct page *allocate_slab(struct
> struct page *page;
> struct kmem_cache_order_objects oo = s->oo;
> gfp_t alloc_gfp;
> + void *start, *p;
> + int idx, order;
>
> flags &= gfp_allowed_mask;
>
> @@ -1364,8 +1377,11 @@ static struct page *allocate_slab(struct
> stat(s, ORDER_FALLBACK);
> }
>
> - if (kmemcheck_enabled && page
> - && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
> + if (!page)
> + goto out;
Since the above now looks like this:
page = alloc_slab_page(s, alloc_gfp, node, oo);
if (unlikely(!page)) {
oo = s->min;
alloc_gfp = flags;
/*
* Allocation may have failed due to fragmentation.
* Try a lower order alloc if possible
*/
page = alloc_slab_page(s, alloc_gfp, node, oo);
if (page)
stat(s, ORDER_FALLBACK);
}
if (!page)
goto out;
Why not have it do this:
page = alloc_slab_page(s, alloc_gfp, node, oo);
if (unlikely(!page)) {
oo = s->min;
alloc_gfp = flags;
/*
* Allocation may have failed due to fragmentation.
* Try a lower order alloc if possible
*/
page = alloc_slab_page(s, alloc_gfp, node, oo);
if (unlikely(!page))
goto out;
stat(s, ORDER_FALLBACK);
}
And get rid of the double check for !page in the fast path.
-- Steve
> +
> + if (kmemcheck_enabled &&
> + !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
> int pages = 1 << oo_order(oo);
>
> kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
> @@ -1380,51 +1396,12 @@ static struct page *allocate_slab(struct
> kmemcheck_mark_unallocated_pages(page, pages);
> }
>
> - if (flags & __GFP_WAIT)
> - local_irq_disable();
> if (!page)
> - return NULL;
> + goto out;
>
> page->objects = oo_objects(oo);
--
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