[PATCH 12/20] percpu: add chunk->base_addr

Tejun Heo
2009-07-21T10:28:04Z

The only thing percpu allocator wants to know about a vmalloc area is
the base address. Instead of requiring chunk->vm, add
chunk->base_addr which contains the necessary value. This simplifies
the code a bit and makes the dummy first_vm unnecessary. This change
will ease allowing a chunk to be mapped by multiple vms.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
mm/percpu.c | 25 +++++++++++--------------
1 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index 8167fb8..7b5e194 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -94,10 +94,11 @@ struct pcpu_chunk {
struct list_head list; /* linked to pcpu_slot lists */
int free_size; /* free bytes in the chunk */
int contig_hint; /* max contiguous size hint */
- struct vm_struct *vm; /* mapped vmalloc region */
+ void *base_addr; /* base address of this 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 */
bool immutable; /* no [de]population allowed */
unsigned long populated[]; /* populated bitmap */
};
@@ -196,7 +197,7 @@ static int pcpu_page_idx(unsigned int cpu, int page_idx)
static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
unsigned int cpu, int page_idx)
{
- return (unsigned long)chunk->vm->addr + pcpu_unit_offsets[cpu] +
+ return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
(page_idx << PAGE_SHIFT);
}

@@ -324,7 +325,7 @@ static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
*/
static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
{
- void *first_start = pcpu_first_chunk->vm->addr;
+ void *first_start = pcpu_first_chunk->base_addr;

/* is it in the first chunk? */
if (addr >= first_start && addr < first_start + pcpu_unit_size) {
@@ -1014,6 +1015,7 @@ 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;

return chunk;
}
@@ -1103,8 +1105,8 @@ area_found:

mutex_unlock(&pcpu_alloc_mutex);

- /* return address relative to unit0 */
- return __addr_to_pcpu_ptr(chunk->vm->addr + off);
+ /* return address relative to base address */
+ return __addr_to_pcpu_ptr(chunk->base_addr + off);

fail_unlock:
spin_unlock_irq(&pcpu_lock);
@@ -1213,7 +1215,7 @@ void free_percpu(void *ptr)
spin_lock_irqsave(&pcpu_lock, flags);

chunk = pcpu_chunk_addr_search(addr);
- off = addr - chunk->vm->addr;
+ off = addr - chunk->base_addr;

pcpu_free_area(chunk, off);

@@ -1565,7 +1567,6 @@ static void pcpu_dump_alloc_info(const char *lvl,
int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
void *base_addr)
{
- static struct vm_struct first_vm;
static int smap[2], dmap[2];
size_t dyn_size = ai->dyn_size;
size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
@@ -1629,10 +1630,6 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);

- first_vm.flags = VM_ALLOC;
- first_vm.size = pcpu_chunk_size;
- first_vm.addr = base_addr;
-
/*
* Allocate chunk slots. The additional last slot is for
* empty chunks.
@@ -1651,7 +1648,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
*/
schunk = alloc_bootmem(pcpu_chunk_struct_size);
INIT_LIST_HEAD(&schunk->list);
- schunk->vm = &first_vm;
+ schunk->base_addr = base_addr;
schunk->map = smap;
schunk->map_alloc = ARRAY_SIZE(smap);
schunk->immutable = true;
@@ -1675,7 +1672,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
if (dyn_size) {
dchunk = alloc_bootmem(pcpu_chunk_struct_size);
INIT_LIST_HEAD(&dchunk->list);
- dchunk->vm = &first_vm;
+ dchunk->base_addr = base_addr;
dchunk->map = dmap;
dchunk->map_alloc = ARRAY_SIZE(dmap);
dchunk->immutable = true;
@@ -1691,7 +1688,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
pcpu_chunk_relocate(pcpu_first_chunk, -1);

/* we're done */
- pcpu_base_addr = schunk->vm->addr;
+ pcpu_base_addr = base_addr;
return 0;
}

--
1.6.0.2