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Date: Mon Nov 17 23:48:26 CST 2008
From: Rusty Russell <rusty@...tcorp.com.au>
To: linux-kernel@...r.kernel.org
Cc: Christoph Lameter <cl@...ux-foundation.org>
Subject: [PATCH 3/7] Improve alloc_percpu: expose percpu_modalloc and percpu_modfree
This simply moves the percpu allocator functions from the module code
to mm/allocpercpu.c. percpu_modinit is renamed percpu_alloc_init and
called from init/main.c.
(Note: this allocator will need to be weaned off krealloc for use in
the slab allocator itself as Christoph does in one of his patches).
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Cc: Christoph Lameter <cl@...ux-foundation.org>
---
include/linux/percpu.h | 11 +++
kernel/module.c | 145 -------------------------------------------------
mm/allocpercpu.c | 134 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 146 insertions(+), 144 deletions(-)
diff -r 81ce6015186e include/linux/percpu.h
--- a/include/linux/percpu.h Mon Nov 17 23:19:14 2008 +1030
+++ b/include/linux/percpu.h Mon Nov 17 23:40:12 2008 +1030
@@ -78,6 +78,8 @@
extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
extern void percpu_free(void *__pdata);
+void *percpu_modalloc(unsigned long size, unsigned long align);
+void percpu_modfree(void *pcpuptr);
#else /* CONFIG_SMP */
#define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
@@ -92,6 +94,15 @@
kfree(__pdata);
}
+static inline void *percpu_modalloc(unsigned long size, unsigned long align)
+{
+ return kzalloc(size);
+}
+
+static inline void percpu_modfree(void *pcpuptr)
+{
+ kfree(pcpuptr);
+}
#endif /* CONFIG_SMP */
#define percpu_alloc_mask(size, gfp, mask) \
@@ -108,4 +119,6 @@
#define free_percpu(ptr) percpu_free((ptr))
#define per_cpu_ptr(ptr, cpu) percpu_ptr((ptr), (cpu))
+void percpu_alloc_init(void);
+
#endif /* __LINUX_PERCPU_H */
diff -r 81ce6015186e init/main.c
--- a/init/main.c Mon Nov 17 23:19:14 2008 +1030
+++ b/init/main.c Mon Nov 17 23:40:12 2008 +1030
@@ -655,6 +655,7 @@
enable_debug_pagealloc();
cpu_hotplug_init();
kmem_cache_init();
+ percpu_alloc_init();
debug_objects_mem_init();
idr_init_cache();
setup_per_cpu_pageset();
diff -r 81ce6015186e kernel/module.c
--- a/kernel/module.c Mon Nov 17 23:19:14 2008 +1030
+++ b/kernel/module.c Mon Nov 17 23:40:12 2008 +1030
@@ -51,6 +51,7 @@
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
+#include <linux/percpu.h>
#if 0
#define DEBUGP printk
@@ -366,123 +367,6 @@
}
#ifdef CONFIG_SMP
-/* Number of blocks used and allocated. */
-static unsigned int pcpu_num_used, pcpu_num_allocated;
-/* Size of each block. -ve means used. */
-static int *pcpu_size;
-
-static int split_block(unsigned int i, unsigned short size)
-{
- /* Reallocation required? */
- if (pcpu_num_used + 1 > pcpu_num_allocated) {
- int *new;
-
- new = krealloc(pcpu_size, sizeof(new[0])*pcpu_num_allocated*2,
- GFP_KERNEL);
- if (!new)
- return 0;
-
- pcpu_num_allocated *= 2;
- pcpu_size = new;
- }
-
- /* Insert a new subblock */
- memmove(&pcpu_size[i+1], &pcpu_size[i],
- sizeof(pcpu_size[0]) * (pcpu_num_used - i));
- pcpu_num_used++;
-
- pcpu_size[i+1] -= size;
- pcpu_size[i] = size;
- return 1;
-}
-
-static inline unsigned int block_size(int val)
-{
- if (val < 0)
- return -val;
- return val;
-}
-
-static void *percpu_modalloc(unsigned long size, unsigned long align)
-{
- unsigned long extra;
- unsigned int i;
- void *ptr;
-
- if (WARN_ON(align > PAGE_SIZE))
- align = PAGE_SIZE;
-
- ptr = __per_cpu_start;
- for (i = 0; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
- /* Extra for alignment requirement. */
- extra = ALIGN((unsigned long)ptr, align) - (unsigned long)ptr;
- BUG_ON(i == 0 && extra != 0);
-
- if (pcpu_size[i] < 0 || pcpu_size[i] < extra + size)
- continue;
-
- /* Transfer extra to previous block. */
- if (pcpu_size[i-1] < 0)
- pcpu_size[i-1] -= extra;
- else
- pcpu_size[i-1] += extra;
- pcpu_size[i] -= extra;
- ptr += extra;
-
- /* Split block if warranted */
- if (pcpu_size[i] - size > sizeof(unsigned long))
- if (!split_block(i, size))
- return NULL;
-
- /* Mark allocated */
- pcpu_size[i] = -pcpu_size[i];
-
- /* Zero since most callers want it and it's a PITA to do. */
- for_each_possible_cpu(i)
- memset(ptr + per_cpu_offset(i), 0, size);
- return ptr;
- }
-
- printk(KERN_WARNING "Could not allocate %lu bytes percpu data\n",
- size);
- return NULL;
-}
-
-static void percpu_modfree(void *freeme)
-{
- unsigned int i;
- void *ptr = __per_cpu_start + block_size(pcpu_size[0]);
-
- if (!freeme)
- return;
-
- /* First entry is core kernel percpu data. */
- for (i = 1; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
- if (ptr == freeme) {
- pcpu_size[i] = -pcpu_size[i];
- goto free;
- }
- }
- BUG();
-
- free:
- /* Merge with previous? */
- if (pcpu_size[i-1] >= 0) {
- pcpu_size[i-1] += pcpu_size[i];
- pcpu_num_used--;
- memmove(&pcpu_size[i], &pcpu_size[i+1],
- (pcpu_num_used - i) * sizeof(pcpu_size[0]));
- i--;
- }
- /* Merge with next? */
- if (i+1 < pcpu_num_used && pcpu_size[i+1] >= 0) {
- pcpu_size[i] += pcpu_size[i+1];
- pcpu_num_used--;
- memmove(&pcpu_size[i+1], &pcpu_size[i+2],
- (pcpu_num_used - (i+1)) * sizeof(pcpu_size[0]));
- }
-}
-
static unsigned int find_pcpusec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings)
@@ -497,34 +381,7 @@
for_each_possible_cpu(cpu)
memcpy(pcpudest + per_cpu_offset(cpu), from, size);
}
-
-static int percpu_modinit(void)
-{
- pcpu_num_used = 2;
- pcpu_num_allocated = 2;
- pcpu_size = kmalloc(sizeof(pcpu_size[0]) * pcpu_num_allocated,
- GFP_KERNEL);
- /* Static in-kernel percpu data (used). */
- pcpu_size[0] = -(__per_cpu_end-__per_cpu_start);
- /* Free room. */
- pcpu_size[1] = PERCPU_ENOUGH_ROOM + pcpu_size[0];
- if (pcpu_size[1] < 0) {
- printk(KERN_ERR "No per-cpu room for modules.\n");
- pcpu_num_used = 1;
- }
-
- return 0;
-}
-__initcall(percpu_modinit);
#else /* ... !CONFIG_SMP */
-static inline void *percpu_modalloc(unsigned long size, unsigned long align)
-{
- return kzalloc(size);
-}
-static inline void percpu_modfree(void *pcpuptr)
-{
- kfree(pcpuptr);
-}
static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
const char *secstrings)
diff -r 81ce6015186e mm/allocpercpu.c
--- a/mm/allocpercpu.c Mon Nov 17 23:19:14 2008 +1030
+++ b/mm/allocpercpu.c Mon Nov 17 23:40:12 2008 +1030
@@ -5,6 +5,7 @@
*/
#include <linux/mm.h>
#include <linux/module.h>
+#include <asm/sections.h>
#ifndef cache_line_size
#define cache_line_size() L1_CACHE_BYTES
@@ -142,6 +143,136 @@
}
EXPORT_SYMBOL_GPL(percpu_free);
+/* Number of blocks used and allocated. */
+static unsigned int pcpu_num_used, pcpu_num_allocated;
+/* Size of each block. -ve means used. */
+static int *pcpu_size;
+
+static int split_block(unsigned int i, unsigned short size)
+{
+ /* Reallocation required? */
+ if (pcpu_num_used + 1 > pcpu_num_allocated) {
+ int *new;
+
+ new = krealloc(pcpu_size, sizeof(new[0])*pcpu_num_allocated*2,
+ GFP_KERNEL);
+ if (!new)
+ return 0;
+
+ pcpu_num_allocated *= 2;
+ pcpu_size = new;
+ }
+
+ /* Insert a new subblock */
+ memmove(&pcpu_size[i+1], &pcpu_size[i],
+ sizeof(pcpu_size[0]) * (pcpu_num_used - i));
+ pcpu_num_used++;
+
+ pcpu_size[i+1] -= size;
+ pcpu_size[i] = size;
+ return 1;
+}
+
+static inline unsigned int block_size(int val)
+{
+ if (val < 0)
+ return -val;
+ return val;
+}
+
+void *percpu_modalloc(unsigned long size, unsigned long align)
+{
+ unsigned long extra;
+ unsigned int i;
+ void *ptr;
+
+ if (WARN_ON(align > PAGE_SIZE))
+ align = PAGE_SIZE;
+
+ ptr = __per_cpu_start;
+ for (i = 0; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
+ /* Extra for alignment requirement. */
+ extra = ALIGN((unsigned long)ptr, align) - (unsigned long)ptr;
+ BUG_ON(i == 0 && extra != 0);
+
+ if (pcpu_size[i] < 0 || pcpu_size[i] < extra + size)
+ continue;
+
+ /* Transfer extra to previous block. */
+ if (pcpu_size[i-1] < 0)
+ pcpu_size[i-1] -= extra;
+ else
+ pcpu_size[i-1] += extra;
+ pcpu_size[i] -= extra;
+ ptr += extra;
+
+ /* Split block if warranted */
+ if (pcpu_size[i] - size > sizeof(unsigned long))
+ if (!split_block(i, size))
+ return NULL;
+
+ /* Mark allocated */
+ pcpu_size[i] = -pcpu_size[i];
+
+ /* Zero since most callers want it and it's a PITA to do. */
+ for_each_possible_cpu(i)
+ memset(ptr + per_cpu_offset(i), 0, size);
+ return ptr;
+ }
+
+ printk(KERN_WARNING "Could not allocate %lu bytes percpu data\n",
+ size);
+ return NULL;
+}
+
+void percpu_modfree(void *freeme)
+{
+ unsigned int i;
+ void *ptr = __per_cpu_start + block_size(pcpu_size[0]);
+
+ if (!freeme)
+ return;
+
+ /* First entry is core kernel percpu data. */
+ for (i = 1; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
+ if (ptr == freeme) {
+ pcpu_size[i] = -pcpu_size[i];
+ goto free;
+ }
+ }
+ BUG();
+
+ free:
+ /* Merge with previous? */
+ if (pcpu_size[i-1] >= 0) {
+ pcpu_size[i-1] += pcpu_size[i];
+ pcpu_num_used--;
+ memmove(&pcpu_size[i], &pcpu_size[i+1],
+ (pcpu_num_used - i) * sizeof(pcpu_size[0]));
+ i--;
+ }
+ /* Merge with next? */
+ if (i+1 < pcpu_num_used && pcpu_size[i+1] >= 0) {
+ pcpu_size[i] += pcpu_size[i+1];
+ pcpu_num_used--;
+ memmove(&pcpu_size[i+1], &pcpu_size[i+2],
+ (pcpu_num_used - (i+1)) * sizeof(pcpu_size[0]));
+ }
+}
+
+void __init percpu_alloc_init(void)
+{
+ pcpu_num_used = 2;
+ pcpu_num_allocated = 2;
+ pcpu_size = kmalloc(sizeof(pcpu_size[0]) * pcpu_num_allocated,
+ GFP_KERNEL);
+ /* Static in-kernel percpu data (used). */
+ pcpu_size[0] = -(__per_cpu_end-__per_cpu_start);
+ /* Free room. */
+ pcpu_size[1] = PERCPU_ENOUGH_ROOM + pcpu_size[0];
+ BUG_ON(pcpu_size[1] < 0);
+}
+
/* A heuristic based on observation. May need to increase. */
unsigned int percpu_reserve = (sizeof(unsigned long) * 2500);
--
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