| Message ID | 1621938235-11947-2-git-send-email-yejunedeng@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] mm: slab/slub: use raw_spinlock_t to define list_lock | expand |
On 5/25/21 12:23 PM, Yejune Deng wrote: > Use DEFINE_RAW_SPINLOCK instead of DEFINE_SPINLOCK object_map_lock > that won't be preempted on mainline and PREEMPT_RT kernels. > > Signed-off-by: Yejune Deng <yejunedeng@gmail.com> RT tree also has such patch, with IMHO more thorough description: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tree/patches/0002-mm-slub-Make-object_map_lock-a-raw_spinlock_t.patch?h=linux-5.12.y-rt-patches I was planning to include that in the next version of my series as that will indeed be necessary. > --- > mm/slub.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > index c2f63c3..995f3d0 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -445,7 +445,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, > > #ifdef CONFIG_SLUB_DEBUG > static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; > -static DEFINE_SPINLOCK(object_map_lock); > +static DEFINE_RAW_SPINLOCK(object_map_lock); > > #if IS_ENABLED(CONFIG_KUNIT) > static bool slab_add_kunit_errors(void) > @@ -481,7 +481,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) > > VM_BUG_ON(!irqs_disabled()); > > - spin_lock(&object_map_lock); > + raw_spin_lock(&object_map_lock); > > bitmap_zero(object_map, page->objects); > > @@ -494,7 +494,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) > static void put_map(unsigned long *map) __releases(&object_map_lock) > { > VM_BUG_ON(map != object_map); > - spin_unlock(&object_map_lock); > + raw_spin_unlock(&object_map_lock); > } > > static inline unsigned int size_from_object(struct kmem_cache *s) >
On Tue, 25 May 2021 12:46:35 +0200 Vlastimil Babka <vbabka@suse.cz> wrote: > On 5/25/21 12:23 PM, Yejune Deng wrote: > > Use DEFINE_RAW_SPINLOCK instead of DEFINE_SPINLOCK object_map_lock > > that won't be preempted on mainline and PREEMPT_RT kernels. > > > > Signed-off-by: Yejune Deng <yejunedeng@gmail.com> > > RT tree also has such patch, with IMHO more thorough description: Yes please, a more thorough decription is needed. The description provided with this patch could be applied to every spinlock in the kernel!
diff --git a/mm/slub.c b/mm/slub.c index c2f63c3..995f3d0 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -445,7 +445,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, #ifdef CONFIG_SLUB_DEBUG static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; -static DEFINE_SPINLOCK(object_map_lock); +static DEFINE_RAW_SPINLOCK(object_map_lock); #if IS_ENABLED(CONFIG_KUNIT) static bool slab_add_kunit_errors(void) @@ -481,7 +481,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) VM_BUG_ON(!irqs_disabled()); - spin_lock(&object_map_lock); + raw_spin_lock(&object_map_lock); bitmap_zero(object_map, page->objects); @@ -494,7 +494,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) static void put_map(unsigned long *map) __releases(&object_map_lock) { VM_BUG_ON(map != object_map); - spin_unlock(&object_map_lock); + raw_spin_unlock(&object_map_lock); } static inline unsigned int size_from_object(struct kmem_cache *s)
Use DEFINE_RAW_SPINLOCK instead of DEFINE_SPINLOCK object_map_lock that won't be preempted on mainline and PREEMPT_RT kernels. Signed-off-by: Yejune Deng <yejunedeng@gmail.com> --- mm/slub.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)