On Mon, Nov 09, 2020 at 12:33:46PM +0100, Vlastimil Babka wrote:
> On 11/8/20 7:57 AM, Mike Rapoport wrote:
> > --- a/mm/slab.c
> > +++ b/mm/slab.c
> > @@ -1428,21 +1428,19 @@ static bool is_debug_pagealloc_cache(struct kmem_cache *cachep)
> > return false;
> > }
> > -#ifdef CONFIG_DEBUG_PAGEALLOC
> > static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map)
> > {
> > if (!is_debug_pagealloc_cache(cachep))
> > return;
>
> Hmm, I didn't notice earlier, sorry.
> The is_debug_pagealloc_cache() above includes a
> debug_pagealloc_enabled_static() check, so it should be fine to use
> __kernel_map_pages() directly below. Otherwise we generate two static key
> checks for the same key needlessly.
Ok, I'll revert slab changes.
> > - kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map);
> > + if (map)
> > + debug_pagealloc_map_pages(virt_to_page(objp),
> > + cachep->size / PAGE_SIZE);
> > + else
> > + debug_pagealloc_unmap_pages(virt_to_page(objp),
> > + cachep->size / PAGE_SIZE);
> > }
> > -#else
> > -static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp,
> > - int map) {}
> > -
> > -#endif
> > -
> > static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
> > {
> > int size = cachep->object_size;
> > @@ -2062,7 +2060,7 @@ int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags)
> > #if DEBUG
> > /*
> > - * If we're going to use the generic kernel_map_pages()
> > + * If we're going to use the generic debug_pagealloc_map_pages()
> > * poisoning, then it's going to smash the contents of
> > * the redzone and userword anyhow, so switch them off.
> > */
> >
>
--
Sincerely yours,
Mike.
