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Groups > linux.kernel > #1695250
| From | Dennis Zhou <dennisz@fb.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v2 02/23] percpu: introduce start_offset to pcpu_chunk |
| Date | 2017-07-25 01:10 +0200 |
| Message-ID | <u6UEb-3ig-47@gated-at.bofh.it> (permalink) |
| References | <u6UE9-3ig-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>
The reserved chunk arithmetic uses a global variable
pcpu_reserved_chunk_limit that is set in the first chunk init code to
hide a portion of the area map. The bitmap allocator to come will
eventually move the base_addr up and require both the reserved chunk
and static chunk to maintain this offset. pcpu_reserved_chunk_limit is
removed and start_offset is added.
The first chunk that is circulated and is pcpu_first_chunk serves the
dynamic region, the region following the reserved region. The reserved
chunk address check will temporarily use the first chunk to identify its
address range. A following patch will increase the base_addr and remove
this. If there is no reserved chunk, this will check the static region
and return false because those values should never be passed into the
allocator.
Lastly, when linking in the first chunk, make sure to count the right
free region for the number of empty populated pages.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
---
mm/percpu-internal.h | 3 +++
mm/percpu.c | 21 ++++++++++-----------
2 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h
index c9158a4..92fc012 100644
--- a/mm/percpu-internal.h
+++ b/mm/percpu-internal.h
@@ -28,6 +28,9 @@ struct pcpu_chunk {
contain reservation for static chunk.
Dynamic chunk will contain reservation
for static and reserved chunks. */
+ int start_offset; /* the overlap with the previous
+ region to have a page aligned
+ base_addr */
int nr_populated; /* # of populated pages */
unsigned long populated[]; /* populated bitmap */
};
diff --git a/mm/percpu.c b/mm/percpu.c
index 3602d41..e94f0d1 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -145,13 +145,10 @@ struct pcpu_chunk *pcpu_first_chunk __ro_after_init;
/*
* Optional reserved chunk. This chunk reserves part of the first
- * chunk and serves it for reserved allocations. The amount of
- * reserved offset is in pcpu_reserved_chunk_limit. When reserved
- * area doesn't exist, the following variables contain NULL and 0
- * respectively.
+ * chunk and serves it for reserved allocations. When the reserved
+ * region doesn't exist, the following variable is NULL.
*/
struct pcpu_chunk *pcpu_reserved_chunk __ro_after_init;
-static int pcpu_reserved_chunk_limit __ro_after_init;
DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop, map ext */
@@ -196,7 +193,7 @@ static bool pcpu_addr_in_reserved_chunk(void *addr)
void *first_start = pcpu_first_chunk->base_addr;
return addr >= first_start &&
- addr < first_start + pcpu_reserved_chunk_limit;
+ addr < first_start + pcpu_first_chunk->start_offset;
}
static int __pcpu_size_to_slot(int size)
@@ -1687,6 +1684,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
INIT_LIST_HEAD(&schunk->list);
INIT_LIST_HEAD(&schunk->map_extend_list);
schunk->base_addr = base_addr;
+ schunk->start_offset = ai->static_size;
schunk->map = smap;
schunk->map_alloc = ARRAY_SIZE(smap);
schunk->immutable = true;
@@ -1696,7 +1694,6 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
if (ai->reserved_size) {
schunk->free_size = ai->reserved_size;
pcpu_reserved_chunk = schunk;
- pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
} else {
schunk->free_size = dyn_size;
dyn_size = 0; /* dynamic area covered */
@@ -1704,7 +1701,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
schunk->contig_hint = schunk->free_size;
schunk->map[0] = 1;
- schunk->map[1] = ai->static_size;
+ schunk->map[1] = schunk->start_offset;
schunk->map[2] = (ai->static_size + schunk->free_size) | 1;
schunk->map_used = 2;
schunk->has_reserved = true;
@@ -1715,6 +1712,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
INIT_LIST_HEAD(&dchunk->list);
INIT_LIST_HEAD(&dchunk->map_extend_list);
dchunk->base_addr = base_addr;
+ dchunk->start_offset = ai->static_size + ai->reserved_size;
dchunk->map = dmap;
dchunk->map_alloc = ARRAY_SIZE(dmap);
dchunk->immutable = true;
@@ -1723,16 +1721,17 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
dchunk->contig_hint = dchunk->free_size = dyn_size;
dchunk->map[0] = 1;
- dchunk->map[1] = pcpu_reserved_chunk_limit;
- dchunk->map[2] = (pcpu_reserved_chunk_limit + dchunk->free_size) | 1;
+ dchunk->map[1] = dchunk->start_offset;
+ dchunk->map[2] = (dchunk->start_offset + dchunk->free_size) | 1;
dchunk->map_used = 2;
dchunk->has_reserved = true;
}
/* link the first chunk in */
pcpu_first_chunk = dchunk ?: schunk;
+ i = (pcpu_first_chunk->start_offset) ? 1 : 0;
pcpu_nr_empty_pop_pages +=
- pcpu_count_occupied_pages(pcpu_first_chunk, 1);
+ pcpu_count_occupied_pages(pcpu_first_chunk, i);
pcpu_chunk_relocate(pcpu_first_chunk, -1);
pcpu_stats_chunk_alloc();
--
2.9.3
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[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
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