| Message ID | 20231120-slab-remove-slab-v2-3-9c9c70177183@suse.cz (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | remove the SLAB allocator | expand |
On Tue, Nov 21, 2023 at 3:34 AM Vlastimil Babka <vbabka@suse.cz> wrote: > > With SLAB removed and SLUB the only remaining allocator, we can clean up > some code that was depending on the choice. > > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Marco Elver <elver@google.com> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > --- [...] > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > index ca4529156735..138c57b836f2 100644 > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > { > void *object = qlink_to_object(qlink, cache); > struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); > - unsigned long flags; > - > - if (IS_ENABLED(CONFIG_SLAB)) > - local_irq_save(flags); > > /* > * If init_on_free is enabled and KASAN's free metadata is stored in > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; > > ___cache_free(cache, object, _THIS_IP_); > - > - if (IS_ENABLED(CONFIG_SLAB)) > - local_irq_restore(flags); > } FYI there's a slight conflict (easy to resolve, though) when I tried to merge this on top of linux-next, due to a recent change in KASAN: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=0e8b630f3053f0ff84b7c3ab8ff98a7393863824 Thanks, Hyeonggon
On Mon, Nov 20, 2023 at 7:34 PM Vlastimil Babka <vbabka@suse.cz> wrote: > > With SLAB removed and SLUB the only remaining allocator, we can clean up > some code that was depending on the choice. > > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Marco Elver <elver@google.com> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/kasan/common.c | 13 ++----------- > mm/kasan/kasan.h | 3 +-- > mm/kasan/quarantine.c | 7 ------- > 3 files changed, 3 insertions(+), 20 deletions(-) > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 256930da578a..5d95219e69d7 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object) > * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be > * accessed after being freed. We preassign tags for objects in these > * caches as well. > - * 3. For SLAB allocator we can't preassign tags randomly since the freelist > - * is stored as an array of indexes instead of a linked list. Assign tags > - * based on objects indexes, so that objects that are next to each other > - * get different tags. > */ > static inline u8 assign_tag(struct kmem_cache *cache, > const void *object, bool init) > @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache, > if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) > return init ? KASAN_TAG_KERNEL : kasan_random_tag(); > > - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ > -#ifdef CONFIG_SLAB > - /* For SLAB assign tags based on the object index in the freelist. */ > - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object); > -#else > /* > - * For SLUB assign a random tag during slab creation, otherwise reuse > + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU, > + * assign a random tag during slab creation, otherwise reuse > * the already assigned tag. > */ > return init ? kasan_random_tag() : get_tag(object); > -#endif > } > > void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index 8b06bab5c406..eef50233640a 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags); > void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags); > void kasan_save_free_info(struct kmem_cache *cache, void *object); > > -#if defined(CONFIG_KASAN_GENERIC) && \ > - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) > +#ifdef CONFIG_KASAN_GENERIC > bool kasan_quarantine_put(struct kmem_cache *cache, void *object); > void kasan_quarantine_reduce(void); > void kasan_quarantine_remove_cache(struct kmem_cache *cache); > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > index ca4529156735..138c57b836f2 100644 > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > { > void *object = qlink_to_object(qlink, cache); > struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); > - unsigned long flags; > - > - if (IS_ENABLED(CONFIG_SLAB)) > - local_irq_save(flags); > > /* > * If init_on_free is enabled and KASAN's free metadata is stored in > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; > > ___cache_free(cache, object, _THIS_IP_); > - > - if (IS_ENABLED(CONFIG_SLAB)) > - local_irq_restore(flags); > } > > static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) > > -- > 2.42.1 > Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Very nice to see SLAB-induced complexity being gone :) Thank you!
On Mon, Nov 20, 2023 at 07:34:14PM +0100, Vlastimil Babka wrote: > With SLAB removed and SLUB the only remaining allocator, we can clean up > some code that was depending on the choice. > > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Marco Elver <elver@google.com> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/kasan/common.c | 13 ++----------- > mm/kasan/kasan.h | 3 +-- > mm/kasan/quarantine.c | 7 ------- > 3 files changed, 3 insertions(+), 20 deletions(-) > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 256930da578a..5d95219e69d7 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object) > * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be > * accessed after being freed. We preassign tags for objects in these > * caches as well. > - * 3. For SLAB allocator we can't preassign tags randomly since the freelist > - * is stored as an array of indexes instead of a linked list. Assign tags > - * based on objects indexes, so that objects that are next to each other > - * get different tags. > */ > static inline u8 assign_tag(struct kmem_cache *cache, > const void *object, bool init) > @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache, > if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) > return init ? KASAN_TAG_KERNEL : kasan_random_tag(); > > - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ > -#ifdef CONFIG_SLAB > - /* For SLAB assign tags based on the object index in the freelist. */ > - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object); > -#else > /* > - * For SLUB assign a random tag during slab creation, otherwise reuse > + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU, > + * assign a random tag during slab creation, otherwise reuse > * the already assigned tag. > */ > return init ? kasan_random_tag() : get_tag(object); > -#endif > } > > void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index 8b06bab5c406..eef50233640a 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags); > void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags); > void kasan_save_free_info(struct kmem_cache *cache, void *object); > > -#if defined(CONFIG_KASAN_GENERIC) && \ > - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) > +#ifdef CONFIG_KASAN_GENERIC > bool kasan_quarantine_put(struct kmem_cache *cache, void *object); > void kasan_quarantine_reduce(void); > void kasan_quarantine_remove_cache(struct kmem_cache *cache); > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > index ca4529156735..138c57b836f2 100644 > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > { > void *object = qlink_to_object(qlink, cache); > struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); > - unsigned long flags; > - > - if (IS_ENABLED(CONFIG_SLAB)) > - local_irq_save(flags); > > /* > * If init_on_free is enabled and KASAN's free metadata is stored in > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; > > ___cache_free(cache, object, _THIS_IP_); > - > - if (IS_ENABLED(CONFIG_SLAB)) > - local_irq_restore(flags); > } > > static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) Looks good to me, Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > > -- > 2.42.1 > >
On Tue, Dec 5, 2023 at 1:27 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote: > > On Mon, Nov 20, 2023 at 07:34:14PM +0100, Vlastimil Babka wrote: > > With SLAB removed and SLUB the only remaining allocator, we can clean up > > some code that was depending on the choice. > > > > Reviewed-by: Kees Cook <keescook@chromium.org> > > Reviewed-by: Marco Elver <elver@google.com> > > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > > --- > > mm/kasan/common.c | 13 ++----------- > > mm/kasan/kasan.h | 3 +-- > > mm/kasan/quarantine.c | 7 ------- > > 3 files changed, 3 insertions(+), 20 deletions(-) > > > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > > index 256930da578a..5d95219e69d7 100644 > > --- a/mm/kasan/common.c > > +++ b/mm/kasan/common.c > > @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object) > > * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be > > * accessed after being freed. We preassign tags for objects in these > > * caches as well. > > - * 3. For SLAB allocator we can't preassign tags randomly since the freelist > > - * is stored as an array of indexes instead of a linked list. Assign tags > > - * based on objects indexes, so that objects that are next to each other > > - * get different tags. > > */ > > static inline u8 assign_tag(struct kmem_cache *cache, > > const void *object, bool init) > > @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache, > > if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) > > return init ? KASAN_TAG_KERNEL : kasan_random_tag(); > > > > - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ > > -#ifdef CONFIG_SLAB > > - /* For SLAB assign tags based on the object index in the freelist. */ > > - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object); > > -#else > > /* > > - * For SLUB assign a random tag during slab creation, otherwise reuse > > + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU, > > + * assign a random tag during slab creation, otherwise reuse > > * the already assigned tag. > > */ > > return init ? kasan_random_tag() : get_tag(object); > > -#endif > > } > > > > void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index 8b06bab5c406..eef50233640a 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags); > > void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags); > > void kasan_save_free_info(struct kmem_cache *cache, void *object); > > > > -#if defined(CONFIG_KASAN_GENERIC) && \ > > - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) > > +#ifdef CONFIG_KASAN_GENERIC > > bool kasan_quarantine_put(struct kmem_cache *cache, void *object); > > void kasan_quarantine_reduce(void); > > void kasan_quarantine_remove_cache(struct kmem_cache *cache); > > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > > index ca4529156735..138c57b836f2 100644 > > --- a/mm/kasan/quarantine.c > > +++ b/mm/kasan/quarantine.c > > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > > { > > void *object = qlink_to_object(qlink, cache); > > struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); > > - unsigned long flags; > > - > > - if (IS_ENABLED(CONFIG_SLAB)) > > - local_irq_save(flags); > > > > /* > > * If init_on_free is enabled and KASAN's free metadata is stored in > > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > > *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; > > > > ___cache_free(cache, object, _THIS_IP_); > > - > > - if (IS_ENABLED(CONFIG_SLAB)) > > - local_irq_restore(flags); > > } > > > > static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) > > Looks good to me, > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> nit: Some KASAN tests depends on SLUB, but as now it's the only allocator KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); in mm/kasan/kasan_test.c can be removed > > > > > -- > > 2.42.1 > > > >
On 12/5/23 05:48, Hyeonggon Yoo wrote: > On Tue, Dec 5, 2023 at 1:27 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote: >> >> On Mon, Nov 20, 2023 at 07:34:14PM +0100, Vlastimil Babka wrote: >> > With SLAB removed and SLUB the only remaining allocator, we can clean up >> > some code that was depending on the choice. >> > >> > Reviewed-by: Kees Cook <keescook@chromium.org> >> > Reviewed-by: Marco Elver <elver@google.com> >> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> >> > --- >> > mm/kasan/common.c | 13 ++----------- >> > mm/kasan/kasan.h | 3 +-- >> > mm/kasan/quarantine.c | 7 ------- >> > 3 files changed, 3 insertions(+), 20 deletions(-) >> > >> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c >> > index 256930da578a..5d95219e69d7 100644 >> > --- a/mm/kasan/common.c >> > +++ b/mm/kasan/common.c >> > @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object) >> > * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be >> > * accessed after being freed. We preassign tags for objects in these >> > * caches as well. >> > - * 3. For SLAB allocator we can't preassign tags randomly since the freelist >> > - * is stored as an array of indexes instead of a linked list. Assign tags >> > - * based on objects indexes, so that objects that are next to each other >> > - * get different tags. >> > */ >> > static inline u8 assign_tag(struct kmem_cache *cache, >> > const void *object, bool init) >> > @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache, >> > if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) >> > return init ? KASAN_TAG_KERNEL : kasan_random_tag(); >> > >> > - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ >> > -#ifdef CONFIG_SLAB >> > - /* For SLAB assign tags based on the object index in the freelist. */ >> > - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object); >> > -#else >> > /* >> > - * For SLUB assign a random tag during slab creation, otherwise reuse >> > + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU, >> > + * assign a random tag during slab creation, otherwise reuse >> > * the already assigned tag. >> > */ >> > return init ? kasan_random_tag() : get_tag(object); >> > -#endif >> > } >> > >> > void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, >> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h >> > index 8b06bab5c406..eef50233640a 100644 >> > --- a/mm/kasan/kasan.h >> > +++ b/mm/kasan/kasan.h >> > @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags); >> > void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags); >> > void kasan_save_free_info(struct kmem_cache *cache, void *object); >> > >> > -#if defined(CONFIG_KASAN_GENERIC) && \ >> > - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) >> > +#ifdef CONFIG_KASAN_GENERIC >> > bool kasan_quarantine_put(struct kmem_cache *cache, void *object); >> > void kasan_quarantine_reduce(void); >> > void kasan_quarantine_remove_cache(struct kmem_cache *cache); >> > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c >> > index ca4529156735..138c57b836f2 100644 >> > --- a/mm/kasan/quarantine.c >> > +++ b/mm/kasan/quarantine.c >> > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) >> > { >> > void *object = qlink_to_object(qlink, cache); >> > struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); >> > - unsigned long flags; >> > - >> > - if (IS_ENABLED(CONFIG_SLAB)) >> > - local_irq_save(flags); >> > >> > /* >> > * If init_on_free is enabled and KASAN's free metadata is stored in >> > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) >> > *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; >> > >> > ___cache_free(cache, object, _THIS_IP_); >> > - >> > - if (IS_ENABLED(CONFIG_SLAB)) >> > - local_irq_restore(flags); >> > } >> > >> > static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) >> >> Looks good to me, >> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Thanks! > nit: Some KASAN tests depends on SLUB, but as now it's the only allocator > KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); in > mm/kasan/kasan_test.c can be removed Hmm I see, but will rather also leave it for later cleanup at this point, thanks! >> >> > >> > -- >> > 2.42.1 >> > >> >
diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 256930da578a..5d95219e69d7 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object) * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be * accessed after being freed. We preassign tags for objects in these * caches as well. - * 3. For SLAB allocator we can't preassign tags randomly since the freelist - * is stored as an array of indexes instead of a linked list. Assign tags - * based on objects indexes, so that objects that are next to each other - * get different tags. */ static inline u8 assign_tag(struct kmem_cache *cache, const void *object, bool init) @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache, if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) return init ? KASAN_TAG_KERNEL : kasan_random_tag(); - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ -#ifdef CONFIG_SLAB - /* For SLAB assign tags based on the object index in the freelist. */ - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object); -#else /* - * For SLUB assign a random tag during slab creation, otherwise reuse + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU, + * assign a random tag during slab creation, otherwise reuse * the already assigned tag. */ return init ? kasan_random_tag() : get_tag(object); -#endif } void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 8b06bab5c406..eef50233640a 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags); void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags); void kasan_save_free_info(struct kmem_cache *cache, void *object); -#if defined(CONFIG_KASAN_GENERIC) && \ - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) +#ifdef CONFIG_KASAN_GENERIC bool kasan_quarantine_put(struct kmem_cache *cache, void *object); void kasan_quarantine_reduce(void); void kasan_quarantine_remove_cache(struct kmem_cache *cache); diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index ca4529156735..138c57b836f2 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) { void *object = qlink_to_object(qlink, cache); struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); - unsigned long flags; - - if (IS_ENABLED(CONFIG_SLAB)) - local_irq_save(flags); /* * If init_on_free is enabled and KASAN's free metadata is stored in @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; ___cache_free(cache, object, _THIS_IP_); - - if (IS_ENABLED(CONFIG_SLAB)) - local_irq_restore(flags); } static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)