Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1695260

[PATCH v2 06/23] percpu: end chunk area maps page aligned for the populated bitmap

From Dennis Zhou <dennisz@fb.com>
Newsgroups linux.kernel
Subject [PATCH v2 06/23] percpu: end chunk area maps page aligned for the populated bitmap
Date 2017-07-25 01:20 +0200
Message-ID <u6UNR-3md-11@gated-at.bofh.it> (permalink)
References <u6UE9-3ig-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>

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>
---
 mm/percpu-internal.h | 3 +++
 mm/percpu-stats.c    | 5 +++--
 mm/percpu.c          | 9 +++++++++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h
index c876b5b..f02f31c 100644
--- a/mm/percpu-internal.h
+++ b/mm/percpu-internal.h
@@ -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 */
 };
diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c
index 32f3550..ffbdb96 100644
--- a/mm/percpu-stats.c
+++ b/mm/percpu-stats.c
@@ -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;
diff --git a/mm/percpu.c b/mm/percpu.c
index 2e785a7..1d2c980 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -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;
 }
 
-- 
2.9.3

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH v2 00/23] percpu: replace percpu area map allocator with bitmap allocator Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
  [PATCH v2 22/23] percpu: update pcpu_find_block_fit to use an iterator Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 22/23] percpu: update pcpu_find_block_fit to use an  iterator Josef Bacik <josef@toxicpanda.com> - 2017-07-25 21:50 +0200
  [PATCH v2 09/23] percpu: combine percpu address checks Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 09/23] percpu: combine percpu address checks Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:30 +0200
  [PATCH v2 02/23] percpu: introduce start_offset to pcpu_chunk Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 02/23] percpu: introduce start_offset to pcpu_chunk Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:10 +0200
  [PATCH v2 13/23] percpu: generalize bitmap (un)populated iterators Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 13/23] percpu: generalize bitmap (un)populated  iterators Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:40 +0200
    Re: [PATCH v2 13/23] percpu: generalize bitmap (un)populated  iterators Tejun Heo <tj@kernel.org> - 2017-07-26 16:10 +0200
  [PATCH v2 08/23] percpu: modify base_addr to be region specific Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 08/23] percpu: modify base_addr to be region specific Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:30 +0200
  [PATCH v2 17/23] percpu: skip chunks if the alloc does not fit in the contig hint Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 17/23] percpu: skip chunks if the alloc does not fit  in the contig hint Josef Bacik <josef@toxicpanda.com> - 2017-07-25 21:50 +0200
  [PATCH v2 19/23] percpu: update alloc path to only scan if contig hints are broken Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 19/23] percpu: update alloc path to only scan if  contig hints are broken Josef Bacik <josef@toxicpanda.com> - 2017-07-25 21:40 +0200
  [PATCH v2 12/23] percpu: increase minimum percpu allocation size and align first regions Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:10 +0200
    Re: [PATCH v2 12/23] percpu: increase minimum percpu allocation size  and align first regions Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:40 +0200
  [PATCH v2 01/23] percpu: setup_first_chunk enforce dynamic region must exist Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:20 +0200
    Re: [PATCH v2 01/23] percpu: setup_first_chunk enforce dynamic  region must exist Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:10 +0200
  [PATCH v2 06/23] percpu: end chunk area maps page aligned for the populated bitmap Dennis Zhou <dennisz@fb.com> - 2017-07-25 01:20 +0200
    Re: [PATCH v2 06/23] percpu: end chunk area maps page aligned for  the populated bitmap Josef Bacik <josef@toxicpanda.com> - 2017-07-25 20:20 +0200
  Re: [PATCH v2 14/23] percpu: replace area map allocator with bitmap  allocator Josef Bacik <josef@toxicpanda.com> - 2017-07-25 21:20 +0200

csiph-web