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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 /mm/percpu-km.c
parent6abad5acac09921f4944af77d3860f82d49f528d (diff)
downloadvexpress-lsk-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 'mm/percpu-km.c')
-rw-r--r--mm/percpu-km.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index df680855540..7037bc73bfa 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -27,7 +27,7 @@
* chunk size is not aligned. percpu-km code will whine about it.
*/
-#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+#if defined(CONFIG_SMP) && defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
#error "contiguous percpu allocation is incompatible with paged first chunk"
#endif