111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
|
/*
|
||
|
|
* mm/percpu-km.c - kernel memory based chunk allocation
|
||
|
|
*
|
||
|
|
* Copyright (C) 2010 SUSE Linux Products GmbH
|
||
|
|
* Copyright (C) 2010 Tejun Heo <tj@kernel.org>
|
||
|
|
*
|
||
|
|
* This file is released under the GPLv2.
|
||
|
|
*
|
||
|
|
* Chunks are allocated as a contiguous kernel memory using gfp
|
||
|
|
* allocation. This is to be used on nommu architectures.
|
||
|
|
*
|
||
|
|
* To use percpu-km,
|
||
|
|
*
|
||
|
|
* - define CONFIG_NEED_PER_CPU_KM from the arch Kconfig.
|
||
|
|
*
|
||
|
|
* - CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK must not be defined. It's
|
||
|
|
* not compatible with PER_CPU_KM. EMBED_FIRST_CHUNK should work
|
||
|
|
* fine.
|
||
|
|
*
|
||
|
|
* - NUMA is not supported. When setting up the first chunk,
|
||
|
|
* @cpu_distance_fn should be NULL or report all CPUs to be nearer
|
||
|
|
* than or at LOCAL_DISTANCE.
|
||
|
|
*
|
||
|
|
* - It's best if the chunk size is power of two multiple of
|
||
|
|
* PAGE_SIZE. Because each chunk is allocated as a contiguous
|
||
|
|
* kernel memory block using alloc_pages(), memory will be wasted if
|
||
|
|
* chunk size is not aligned. percpu-km code will whine about it.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#if defined(CONFIG_SMP) && defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
|
||
|
|
#error "contiguous percpu allocation is incompatible with paged first chunk"
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#include <linux/log2.h>
|
||
|
|
|
||
|
|
static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
|
||
|
|
int page_start, int page_end)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
|
||
|
|
int page_start, int page_end)
|
||
|
|
{
|
||
|
|
/* nada */
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct pcpu_chunk *pcpu_create_chunk(void)
|
||
|
|
{
|
||
|
|
const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
|
||
|
|
struct pcpu_chunk *chunk;
|
||
|
|
struct page *pages;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
chunk = pcpu_alloc_chunk();
|
||
|
|
if (!chunk)
|
||
|
|
return NULL;
|
||
|
|
|
||
|
|
pages = alloc_pages(GFP_KERNEL, order_base_2(nr_pages));
|
||
|
|
if (!pages) {
|
||
|
|
pcpu_free_chunk(chunk);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
for (i = 0; i < nr_pages; i++)
|
||
|
|
pcpu_set_page_chunk(nth_page(pages, i), chunk);
|
||
|
|
|
||
|
|
chunk->data = pages;
|
||
|
|
chunk->base_addr = page_address(pages) - pcpu_group_offsets[0];
|
||
|
|
|
||
|
|
spin_lock_irq(&pcpu_lock);
|
||
|
|
pcpu_chunk_populated(chunk, 0, nr_pages);
|
||
|
|
spin_unlock_irq(&pcpu_lock);
|
||
|
|
|
||
|
|
return chunk;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
|
||
|
|
{
|
||
|
|
const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
|
||
|
|
|
||
|
|
if (chunk && chunk->data)
|
||
|
|
__free_pages(chunk->data, order_base_2(nr_pages));
|
||
|
|
pcpu_free_chunk(chunk);
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct page *pcpu_addr_to_page(void *addr)
|
||
|
|
{
|
||
|
|
return virt_to_page(addr);
|
||
|
|
}
|
||
|
|
|
||
|
|
static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
|
||
|
|
{
|
||
|
|
size_t nr_pages, alloc_pages;
|
||
|
|
|
||
|
|
/* all units must be in a single group */
|
||
|
|
if (ai->nr_groups != 1) {
|
||
|
|
pr_crit("can't handle more than one group\n");
|
||
|
|
return -EINVAL;
|
||
|
|
}
|
||
|
|
|
||
|
|
nr_pages = (ai->groups[0].nr_units * ai->unit_size) >> PAGE_SHIFT;
|
||
|
|
alloc_pages = roundup_pow_of_two(nr_pages);
|
||
|
|
|
||
|
|
if (alloc_pages > nr_pages)
|
||
|
|
pr_warn("wasting %zu pages per chunk\n",
|
||
|
|
alloc_pages - nr_pages);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|