path: root/include/linux/percpu.h
diff options
authorTejun Heo <>2009-08-14 15:00:51 +0900
committerTejun Heo <>2009-08-14 15:00:51 +0900
commitfd1e8a1fe2b54df6c185b4fa65f181f50b9c4d4e (patch)
treed4411507baacaa33c68be7813ad6f9e0d93a74e2 /include/linux/percpu.h
parent033e48fb82958053113178264ddb9d5038d5e38b (diff)
percpu: introduce pcpu_alloc_info and pcpu_group_info
Till now, non-linear cpu->unit map was expressed using an integer array which maps each cpu to a unit and used only by lpage allocator. Although how many units have been placed in a single contiguos area (group) is known while building unit_map, the information is lost when the result is recorded into the unit_map array. For lpage allocator, as all allocations are done by lpages and whether two adjacent lpages are in the same group or not is irrelevant, this didn't cause any problem. Non-linear cpu->unit mapping will be used for sparse embedding and this grouping information is necessary for that. This patch introduces pcpu_alloc_info which contains all the information necessary for initializing percpu allocator. pcpu_alloc_info contains array of pcpu_group_info which describes how units are grouped and mapped to cpus. pcpu_group_info also has base_offset field to specify its offset from the chunk's base address. pcpu_build_alloc_info() initializes this field as if all groups are allocated back-to-back as is currently done but this will be used to sparsely place groups. pcpu_alloc_info is a rather complex data structure which contains a flexible array which in turn points to nested cpu_map arrays. * pcpu_alloc_alloc_info() and pcpu_free_alloc_info() are provided to help dealing with pcpu_alloc_info. * pcpu_lpage_build_unit_map() is updated to build pcpu_alloc_info, generalized and renamed to pcpu_build_alloc_info(). @cpu_distance_fn may be NULL indicating that all cpus are of LOCAL_DISTANCE. * pcpul_lpage_dump_cfg() is updated to process pcpu_alloc_info, generalized and renamed to pcpu_dump_alloc_info(). It now also prints which group each alloc unit belongs to. * pcpu_setup_first_chunk() now takes pcpu_alloc_info instead of the separate parameters. All first chunk allocators are updated to use pcpu_build_alloc_info() to build alloc_info and call pcpu_setup_first_chunk() with it. This has the side effect of packing units for sparse possible cpus. ie. if cpus 0, 2 and 4 are possible, they'll be assigned unit 0, 1 and 2 instead of 0, 2 and 4. * x86 setup_pcpu_lpage() is updated to deal with alloc_info. * sparc64 setup_per_cpu_areas() is updated to build alloc_info. Although the changes made by this patch are pretty pervasive, it doesn't cause any behavior difference other than packing of sparse cpus. It mostly changes how information is passed among initialization functions and makes room for more flexibility. Signed-off-by: Tejun Heo <> Cc: Ingo Molnar <> Cc: David Miller <>
Diffstat (limited to 'include/linux/percpu.h')
1 files changed, 29 insertions, 13 deletions
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 570fb18de2ba..77b86be8ce4f 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -59,6 +59,25 @@
extern void *pcpu_base_addr;
extern const int *pcpu_unit_map;
+struct pcpu_group_info {
+ int nr_units; /* aligned # of units */
+ unsigned long base_offset; /* base address offset */
+ unsigned int *cpu_map; /* unit->cpu map, empty
+ * entries contain NR_CPUS */
+struct pcpu_alloc_info {
+ size_t static_size;
+ size_t reserved_size;
+ size_t dyn_size;
+ size_t unit_size;
+ size_t atom_size;
+ size_t alloc_size;
+ size_t __ai_size; /* internal, don't use */
+ int nr_groups; /* 0 if grouping unnecessary */
+ struct pcpu_group_info groups[];
enum pcpu_fc {
@@ -78,18 +97,17 @@ typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr);
-extern int __init pcpu_lpage_build_unit_map(
- size_t reserved_size, ssize_t *dyn_sizep,
- size_t *unit_sizep, size_t lpage_size,
- int *unit_map,
+extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
+ int nr_units);
+extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
+extern struct pcpu_alloc_info * __init pcpu_build_alloc_info(
+ size_t reserved_size, ssize_t dyn_size,
+ size_t atom_size,
pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
-extern size_t __init pcpu_setup_first_chunk(
- size_t static_size, size_t reserved_size,
- size_t dyn_size, size_t unit_size,
- void *base_addr, const int *unit_map);
+extern size_t __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
+ void *base_addr);
extern ssize_t __init pcpu_embed_first_chunk(
@@ -106,9 +124,7 @@ extern ssize_t __init pcpu_page_first_chunk(
extern ssize_t __init pcpu_lpage_first_chunk(
- size_t reserved_size, size_t dyn_size,
- size_t unit_size, size_t lpage_size,
- const int *unit_map, int nr_units,
+ const struct pcpu_alloc_info *ai,
pcpu_fc_alloc_fn_t alloc_fn,
pcpu_fc_free_fn_t free_fn,
pcpu_fc_map_fn_t map_fn);