percpu: don't put the first chunk in reverse-map rbtree
Impact: both first chunks don't use rbtree, no functional change
There can be two first chunks - reserved and dynamic with the former
one being optional. Dynamic first chunk was linked on reverse-mapping
rbtree while the reserved one was mapped manually using the start
address and reserved offset limit.
This patch makes both first chunks to be looked up manually without
using the rbtree. This is to help getting rid of the rbtree.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: rusty@rustcorp.com.au
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: rmk@arm.linux.org.uk
Cc: starvik@axis.com
Cc: ralf@linux-mips.org
Cc: davem@davemloft.net
Cc: cooloney@kernel.org
Cc: kyle@mcmartin.ca
Cc: matthew@wil.cx
Cc: grundler@parisc-linux.org
Cc: takata@linux-m32r.org
Cc: benh@kernel.crashing.org
Cc: rth@twiddle.net
Cc: ink@jurassic.park.msu.ru
Cc: heiko.carstens@de.ibm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux.com>
LKML-Reference: <49D43CEA.3040609@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/mm/percpu.c b/mm/percpu.c
index 1aa5d8f..bf1bf1f 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -110,9 +110,21 @@
void *pcpu_base_addr __read_mostly;
EXPORT_SYMBOL_GPL(pcpu_base_addr);
-/* optional reserved chunk, only accessible for reserved allocations */
+/*
+ * The first chunk which always exists. Note that unlike other
+ * chunks, this one can be allocated and mapped in several different
+ * ways and thus often doesn't live in the vmalloc area.
+ */
+static struct pcpu_chunk *pcpu_first_chunk;
+
+/*
+ * 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.
+ */
static struct pcpu_chunk *pcpu_reserved_chunk;
-/* offset limit of the reserved chunk */
static int pcpu_reserved_chunk_limit;
/*
@@ -297,15 +309,16 @@
*/
static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
{
+ void *first_start = pcpu_first_chunk->vm->addr;
struct rb_node *n, *parent;
struct pcpu_chunk *chunk;
- /* is it in the reserved chunk? */
- if (pcpu_reserved_chunk) {
- void *start = pcpu_reserved_chunk->vm->addr;
-
- if (addr >= start && addr < start + pcpu_reserved_chunk_limit)
+ /* is it in the first chunk? */
+ if (addr >= first_start && addr < first_start + pcpu_chunk_size) {
+ /* is it in the reserved area? */
+ if (addr < first_start + pcpu_reserved_chunk_limit)
return pcpu_reserved_chunk;
+ return pcpu_first_chunk;
}
/* nah... search the regular ones */
@@ -1147,7 +1160,8 @@
if (reserved_size) {
schunk->free_size = reserved_size;
- pcpu_reserved_chunk = schunk; /* not for dynamic alloc */
+ pcpu_reserved_chunk = schunk;
+ pcpu_reserved_chunk_limit = static_size + reserved_size;
} else {
schunk->free_size = dyn_size;
dyn_size = 0; /* dynamic area covered */
@@ -1158,8 +1172,6 @@
if (schunk->free_size)
schunk->map[schunk->map_used++] = schunk->free_size;
- pcpu_reserved_chunk_limit = static_size + schunk->free_size;
-
/* init dynamic chunk if necessary */
if (dyn_size) {
dchunk = alloc_bootmem(sizeof(struct pcpu_chunk));
@@ -1226,13 +1238,8 @@
}
/* link the first chunk in */
- if (!dchunk) {
- pcpu_chunk_relocate(schunk, -1);
- pcpu_chunk_addr_insert(schunk);
- } else {
- pcpu_chunk_relocate(dchunk, -1);
- pcpu_chunk_addr_insert(dchunk);
- }
+ pcpu_first_chunk = dchunk ?: schunk;
+ pcpu_chunk_relocate(pcpu_first_chunk, -1);
/* we're done */
pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0);