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authorTejun Heo <tj@kernel.org>2010-09-03 18:22:48 +0200
committerTejun Heo <tj@kernel.org>2010-09-08 11:11:23 +0200
commitbbddff0545878a8649c091a9dd7c43ce91516734 (patch)
tree667714de4398d1589605555650cf7431a27e1a13 /include/linux/percpu.h
parent6abad5acac09921f4944af77d3860f82d49f528d (diff)
downloadop-kernel-dev-bbddff0545878a8649c091a9dd7c43ce91516734.zip
op-kernel-dev-bbddff0545878a8649c091a9dd7c43ce91516734.tar.gz
percpu: use percpu allocator on UP too
On UP, percpu allocations were redirected to kmalloc. This has the following problems. * For certain amount of allocations (determined by PERCPU_DYNAMIC_EARLY_SLOTS and PERCPU_DYNAMIC_EARLY_SIZE), percpu allocator can be used before the usual kernel memory allocator is brought online. On SMP, this is used to initialize the kernel memory allocator. * percpu allocator honors alignment upto PAGE_SIZE but kmalloc() doesn't. For example, workqueue makes use of larger alignments for cpu_workqueues. Currently, users of percpu allocators need to handle UP differently, which is somewhat fragile and ugly. Other than small amount of memory, there isn't much to lose by enabling percpu allocator on UP. It can simply use kernel memory based chunk allocation which was added for SMP archs w/o MMUs. This patch removes mm/percpu_up.c, builds mm/percpu.c on UP too and makes UP build use percpu-km. As percpu addresses and kernel addresses are always identity mapped and static percpu variables don't need any special treatment, nothing is arch dependent and mm/percpu.c implements generic setup_per_cpu_areas() for UP. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Diffstat (limited to 'include/linux/percpu.h')
-rw-r--r--include/linux/percpu.h29
1 files changed, 5 insertions, 24 deletions
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index fc8130a..aeeeef1 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -39,8 +39,6 @@
preempt_enable(); \
} while (0)
-#ifdef CONFIG_SMP
-
/* minimum unit size, also is the maximum supported allocation size */
#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(32 << 10)
@@ -137,37 +135,20 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
* dynamically allocated. Non-atomic access to the current CPU's
* version should probably be combined with get_cpu()/put_cpu().
*/
+#ifdef CONFIG_SMP
#define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
+#else
+#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); VERIFY_PERCPU_PTR((ptr)); })
+#endif
extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
extern bool is_kernel_percpu_address(unsigned long addr);
-#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
+#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
extern void __init setup_per_cpu_areas(void);
#endif
extern void __init percpu_init_late(void);
-#else /* CONFIG_SMP */
-
-#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); VERIFY_PERCPU_PTR((ptr)); })
-
-/* can't distinguish from other static vars, always false */
-static inline bool is_kernel_percpu_address(unsigned long addr)
-{
- return false;
-}
-
-static inline void __init setup_per_cpu_areas(void) { }
-
-static inline void __init percpu_init_late(void) { }
-
-static inline void *pcpu_lpage_remapped(void *kaddr)
-{
- return NULL;
-}
-
-#endif /* CONFIG_SMP */
-
extern void __percpu *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void __percpu *__pdata);
extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
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