[PATCH 15/20] percpu: use group information to allocate vmap areas sparsely

Tejun Heo
2009-07-21T10:27:59Z

ai->groups[] contains which units need to be put consecutively and at
what offset from the chunk base address. Compile this information
into pcpu_group_offsets[] and pcpu_group_sizes[] in
pcpu_setup_first_chunk() and use them to allocate sparse vm areas
using pcpu_get_vm_areas().

This will be used to allow directly using sparse NUMA memories as
percpu areas.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <npiggin@suse.de>
---
mm/percpu.c | 35 ++++++++++++++++++++++++++---------
1 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index 7b5e194..cc9c4c6 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -98,7 +98,7 @@ struct pcpu_chunk {
int map_used; /* # of map entries used */
int map_alloc; /* # of map entries allocated */
int *map; /* allocation map */
- struct vm_struct *vm; /* mapped vmalloc region */
+ struct vm_struct **vms; /* mapped vmalloc regions */
bool immutable; /* no [de]population allowed */
unsigned long populated[]; /* populated bitmap */
};
@@ -106,7 +106,7 @@ struct pcpu_chunk {
static int pcpu_unit_pages __read_mostly;
static int pcpu_unit_size __read_mostly;
static int pcpu_nr_units __read_mostly;
-static int pcpu_chunk_size __read_mostly;
+static int pcpu_atom_size __read_mostly;
static int pcpu_nr_slots __read_mostly;
static size_t pcpu_chunk_struct_size __read_mostly;

@@ -121,6 +121,11 @@ EXPORT_SYMBOL_GPL(pcpu_base_addr);
static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */

+/* group information, used for vm allocation */
+static int pcpu_nr_groups __read_mostly;
+static const unsigned long *pcpu_group_offsets __read_mostly;
+static const size_t *pcpu_group_sizes __read_mostly;
+
/*
* The first chunk which always exists. Note that unlike other
* chunks, this one can be allocated and mapped in several different
@@ -988,8 +993,8 @@ static void free_pcpu_chunk(struct pcpu_chunk *chunk)
{
if (!chunk)
return;
- if (chunk->vm)
- free_vm_area(chunk->vm);
+ if (chunk->vms)
+ pcpu_free_vm_areas(chunk->vms, pcpu_nr_groups);
pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
kfree(chunk);
}
@@ -1006,8 +1011,10 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
chunk->map[chunk->map_used++] = pcpu_unit_size;

- chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL);
- if (!chunk->vm) {
+ chunk->vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
+ pcpu_nr_groups, pcpu_atom_size,
+ GFP_KERNEL);
+ if (!chunk->vms) {
free_pcpu_chunk(chunk);
return NULL;
}
@@ -1015,7 +1022,7 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
INIT_LIST_HEAD(&chunk->list);
chunk->free_size = pcpu_unit_size;
chunk->contig_hint = pcpu_unit_size;
- chunk->base_addr = chunk->vm->addr;
+ chunk->base_addr = chunk->vms[0]->addr - pcpu_group_offsets[0];

return chunk;
}
@@ -1571,6 +1578,8 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
size_t dyn_size = ai->dyn_size;
size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
struct pcpu_chunk *schunk, *dchunk = NULL;
+ unsigned long *group_offsets;
+ size_t *group_sizes;
unsigned long *unit_off;
unsigned int cpu;
int *unit_map;
@@ -1588,7 +1597,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,

pcpu_dump_alloc_info(KERN_DEBUG, ai);

- /* determine number of units and initialize unit_map and base */
+ /* process group information and build config tables accordingly */
+ group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
+ group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0]));
unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));

@@ -1599,6 +1610,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
const struct pcpu_group_info *gi = &ai->groups[group];

+ group_offsets[group] = gi->base_offset;
+ group_sizes[group] = gi->nr_units * ai->unit_size;
+
for (i = 0; i < gi->nr_units; i++) {
cpu = gi->cpu_map[i];
if (cpu == NR_CPUS)
@@ -1620,13 +1634,16 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
for_each_possible_cpu(cpu)
BUG_ON(unit_map[cpu] == NR_CPUS);

+ pcpu_nr_groups = ai->nr_groups;
+ pcpu_group_offsets = group_offsets;
+ pcpu_group_sizes = group_sizes;
pcpu_unit_map = unit_map;
pcpu_unit_offsets = unit_off;

/* determine basic parameters */
pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
- pcpu_chunk_size = pcpu_nr_units * pcpu_unit_size;
+ pcpu_atom_size = ai->atom_size;
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);

--
1.6.0.2