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percpu: end chunk area maps page aligned for the populated bitmap 

The area map allocator manages the first chunk area by hiding all but
the region it is responsible for serving in the area map. To align this
with the populated page bitmap, end_offset is introduced to keep track
of the delta to end page aligned. The area map is appended with the
page aligned end when necessary to be in line with how the bitmap
allocator requires the ending to be aligned with the LCM of PAGE_SIZE
and the size of each bitmap block. percpu_stats is updated to ignore
this region when present.

Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Dennis Zhou (Facebook) 2017-07-24 19:02:03 -04:00 committed by Tejun Heo
parent 10edf5b0b6
commit 6b9d7c8e8e
3 changed files with 15 additions and 2 deletions
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3
mm/percpu-internal.h
View File

@ -26,6 +26,9 @@ struct pcpu_chunk {
int start_offset; /* the overlap with the previous
region to have a page aligned
base_addr */
int end_offset; /* additional area required to
have the region end page
aligned */
int nr_populated; /* # of populated pages */
unsigned long populated[]; /* populated bitmap */
};

5
mm/percpu-stats.c
View File

@ -51,7 +51,7 @@ static int find_max_map_used(void)
static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk,
int *buffer)
{
int i, s_index, last_alloc, alloc_sign, as_len;
int i, s_index, e_index, last_alloc, alloc_sign, as_len;
int *alloc_sizes, *p;
/* statistics */
int sum_frag = 0, max_frag = 0;
@ -59,10 +59,11 @@ static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk,
alloc_sizes = buffer;
s_index = (chunk->start_offset) ? 1 : 0;
e_index = chunk->map_used - ((chunk->end_offset) ? 1 : 0);
/* find last allocation */
last_alloc = -1;
for (i = chunk->map_used - 1; i >= s_index; i--) {
for (i = e_index - 1; i >= s_index; i--) {
if (chunk->map[i] & 1) {
last_alloc = i;
break;

9
mm/percpu.c
View File

@ -715,12 +715,16 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(void *base_addr,
int init_map_size)
{
struct pcpu_chunk *chunk;
int region_size;
region_size = PFN_ALIGN(start_offset + map_size);
chunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
INIT_LIST_HEAD(&chunk->list);
INIT_LIST_HEAD(&chunk->map_extend_list);
chunk->base_addr = base_addr;
chunk->start_offset = start_offset;
chunk->end_offset = region_size - chunk->start_offset - map_size;
chunk->map = map;
chunk->map_alloc = init_map_size;
@ -735,6 +739,11 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(void *base_addr,
chunk->map[2] = (chunk->start_offset + chunk->free_size) | 1;
chunk->map_used = 2;
if (chunk->end_offset) {
/* hide the end of the bitmap */
chunk->map[++chunk->map_used] = region_size | 1;
}
return chunk;
}