1587 lines
45 KiB
C
1587 lines
45 KiB
C
/*
|
|
* linux/mm/percpu.c - percpu memory allocator
|
|
*
|
|
* Copyright (C) 2009 SUSE Linux Products GmbH
|
|
* Copyright (C) 2009 Tejun Heo <tj@kernel.org>
|
|
*
|
|
* This file is released under the GPLv2.
|
|
*
|
|
* This is percpu allocator which can handle both static and dynamic
|
|
* areas. Percpu areas are allocated in chunks in vmalloc area. Each
|
|
* chunk is consisted of num_possible_cpus() units and the first chunk
|
|
* is used for static percpu variables in the kernel image (special
|
|
* boot time alloc/init handling necessary as these areas need to be
|
|
* brought up before allocation services are running). Unit grows as
|
|
* necessary and all units grow or shrink in unison. When a chunk is
|
|
* filled up, another chunk is allocated. ie. in vmalloc area
|
|
*
|
|
* c0 c1 c2
|
|
* ------------------- ------------------- ------------
|
|
* | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
|
|
* ------------------- ...... ------------------- .... ------------
|
|
*
|
|
* Allocation is done in offset-size areas of single unit space. Ie,
|
|
* an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
|
|
* c1:u1, c1:u2 and c1:u3. Percpu access can be done by configuring
|
|
* percpu base registers pcpu_unit_size apart.
|
|
*
|
|
* There are usually many small percpu allocations many of them as
|
|
* small as 4 bytes. The allocator organizes chunks into lists
|
|
* according to free size and tries to allocate from the fullest one.
|
|
* Each chunk keeps the maximum contiguous area size hint which is
|
|
* guaranteed to be eqaul to or larger than the maximum contiguous
|
|
* area in the chunk. This helps the allocator not to iterate the
|
|
* chunk maps unnecessarily.
|
|
*
|
|
* Allocation state in each chunk is kept using an array of integers
|
|
* on chunk->map. A positive value in the map represents a free
|
|
* region and negative allocated. Allocation inside a chunk is done
|
|
* by scanning this map sequentially and serving the first matching
|
|
* entry. This is mostly copied from the percpu_modalloc() allocator.
|
|
* Chunks can be determined from the address using the index field
|
|
* in the page struct. The index field contains a pointer to the chunk.
|
|
*
|
|
* To use this allocator, arch code should do the followings.
|
|
*
|
|
* - drop CONFIG_HAVE_LEGACY_PER_CPU_AREA
|
|
*
|
|
* - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
|
|
* regular address to percpu pointer and back if they need to be
|
|
* different from the default
|
|
*
|
|
* - use pcpu_setup_first_chunk() during percpu area initialization to
|
|
* setup the first chunk containing the kernel static percpu area
|
|
*/
|
|
|
|
#include <linux/bitmap.h>
|
|
#include <linux/bootmem.h>
|
|
#include <linux/list.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/pfn.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/workqueue.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/sections.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
|
|
#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
|
|
|
|
/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
|
|
#ifndef __addr_to_pcpu_ptr
|
|
#define __addr_to_pcpu_ptr(addr) \
|
|
(void *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr \
|
|
+ (unsigned long)__per_cpu_start)
|
|
#endif
|
|
#ifndef __pcpu_ptr_to_addr
|
|
#define __pcpu_ptr_to_addr(ptr) \
|
|
(void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr \
|
|
- (unsigned long)__per_cpu_start)
|
|
#endif
|
|
|
|
struct pcpu_chunk {
|
|
struct list_head list; /* linked to pcpu_slot lists */
|
|
int free_size; /* free bytes in the chunk */
|
|
int contig_hint; /* max contiguous size hint */
|
|
struct vm_struct *vm; /* mapped vmalloc region */
|
|
int map_used; /* # of map entries used */
|
|
int map_alloc; /* # of map entries allocated */
|
|
int *map; /* allocation map */
|
|
bool immutable; /* no [de]population allowed */
|
|
struct page **page; /* points to page array */
|
|
struct page *page_ar[]; /* #cpus * UNIT_PAGES */
|
|
};
|
|
|
|
static int pcpu_unit_pages __read_mostly;
|
|
static int pcpu_unit_size __read_mostly;
|
|
static int pcpu_chunk_size __read_mostly;
|
|
static int pcpu_nr_slots __read_mostly;
|
|
static size_t pcpu_chunk_struct_size __read_mostly;
|
|
|
|
/* the address of the first chunk which starts with the kernel static area */
|
|
void *pcpu_base_addr __read_mostly;
|
|
EXPORT_SYMBOL_GPL(pcpu_base_addr);
|
|
|
|
/*
|
|
* 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;
|
|
static int pcpu_reserved_chunk_limit;
|
|
|
|
/*
|
|
* Synchronization rules.
|
|
*
|
|
* There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
|
|
* protects allocation/reclaim paths, chunks and chunk->page arrays.
|
|
* The latter is a spinlock and protects the index data structures -
|
|
* chunk slots, chunks and area maps in chunks.
|
|
*
|
|
* During allocation, pcpu_alloc_mutex is kept locked all the time and
|
|
* pcpu_lock is grabbed and released as necessary. All actual memory
|
|
* allocations are done using GFP_KERNEL with pcpu_lock released.
|
|
*
|
|
* Free path accesses and alters only the index data structures, so it
|
|
* can be safely called from atomic context. When memory needs to be
|
|
* returned to the system, free path schedules reclaim_work which
|
|
* grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
|
|
* reclaimed, release both locks and frees the chunks. Note that it's
|
|
* necessary to grab both locks to remove a chunk from circulation as
|
|
* allocation path might be referencing the chunk with only
|
|
* pcpu_alloc_mutex locked.
|
|
*/
|
|
static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
|
|
static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
|
|
|
|
static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
|
|
|
|
/* reclaim work to release fully free chunks, scheduled from free path */
|
|
static void pcpu_reclaim(struct work_struct *work);
|
|
static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
|
|
|
|
static int __pcpu_size_to_slot(int size)
|
|
{
|
|
int highbit = fls(size); /* size is in bytes */
|
|
return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
|
|
}
|
|
|
|
static int pcpu_size_to_slot(int size)
|
|
{
|
|
if (size == pcpu_unit_size)
|
|
return pcpu_nr_slots - 1;
|
|
return __pcpu_size_to_slot(size);
|
|
}
|
|
|
|
static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
|
|
{
|
|
if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
|
|
return 0;
|
|
|
|
return pcpu_size_to_slot(chunk->free_size);
|
|
}
|
|
|
|
static int pcpu_page_idx(unsigned int cpu, int page_idx)
|
|
{
|
|
return cpu * pcpu_unit_pages + page_idx;
|
|
}
|
|
|
|
static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
|
|
unsigned int cpu, int page_idx)
|
|
{
|
|
return (unsigned long)chunk->vm->addr +
|
|
(pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT);
|
|
}
|
|
|
|
static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk,
|
|
unsigned int cpu, int page_idx)
|
|
{
|
|
return &chunk->page[pcpu_page_idx(cpu, page_idx)];
|
|
}
|
|
|
|
static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
|
|
int page_idx)
|
|
{
|
|
return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
|
|
}
|
|
|
|
/* set the pointer to a chunk in a page struct */
|
|
static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
|
|
{
|
|
page->index = (unsigned long)pcpu;
|
|
}
|
|
|
|
/* obtain pointer to a chunk from a page struct */
|
|
static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
|
|
{
|
|
return (struct pcpu_chunk *)page->index;
|
|
}
|
|
|
|
/**
|
|
* pcpu_mem_alloc - allocate memory
|
|
* @size: bytes to allocate
|
|
*
|
|
* Allocate @size bytes. If @size is smaller than PAGE_SIZE,
|
|
* kzalloc() is used; otherwise, vmalloc() is used. The returned
|
|
* memory is always zeroed.
|
|
*
|
|
* CONTEXT:
|
|
* Does GFP_KERNEL allocation.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
static void *pcpu_mem_alloc(size_t size)
|
|
{
|
|
if (size <= PAGE_SIZE)
|
|
return kzalloc(size, GFP_KERNEL);
|
|
else {
|
|
void *ptr = vmalloc(size);
|
|
if (ptr)
|
|
memset(ptr, 0, size);
|
|
return ptr;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pcpu_mem_free - free memory
|
|
* @ptr: memory to free
|
|
* @size: size of the area
|
|
*
|
|
* Free @ptr. @ptr should have been allocated using pcpu_mem_alloc().
|
|
*/
|
|
static void pcpu_mem_free(void *ptr, size_t size)
|
|
{
|
|
if (size <= PAGE_SIZE)
|
|
kfree(ptr);
|
|
else
|
|
vfree(ptr);
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_relocate - put chunk in the appropriate chunk slot
|
|
* @chunk: chunk of interest
|
|
* @oslot: the previous slot it was on
|
|
*
|
|
* This function is called after an allocation or free changed @chunk.
|
|
* New slot according to the changed state is determined and @chunk is
|
|
* moved to the slot. Note that the reserved chunk is never put on
|
|
* chunk slots.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*/
|
|
static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
|
|
{
|
|
int nslot = pcpu_chunk_slot(chunk);
|
|
|
|
if (chunk != pcpu_reserved_chunk && oslot != nslot) {
|
|
if (oslot < nslot)
|
|
list_move(&chunk->list, &pcpu_slot[nslot]);
|
|
else
|
|
list_move_tail(&chunk->list, &pcpu_slot[nslot]);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_addr_search - determine chunk containing specified address
|
|
* @addr: address for which the chunk needs to be determined.
|
|
*
|
|
* RETURNS:
|
|
* The address of the found chunk.
|
|
*/
|
|
static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
|
|
{
|
|
void *first_start = pcpu_first_chunk->vm->addr;
|
|
|
|
/* is it in the first chunk? */
|
|
if (addr >= first_start && addr < first_start + pcpu_unit_size) {
|
|
/* is it in the reserved area? */
|
|
if (addr < first_start + pcpu_reserved_chunk_limit)
|
|
return pcpu_reserved_chunk;
|
|
return pcpu_first_chunk;
|
|
}
|
|
|
|
return pcpu_get_page_chunk(vmalloc_to_page(addr));
|
|
}
|
|
|
|
/**
|
|
* pcpu_extend_area_map - extend area map for allocation
|
|
* @chunk: target chunk
|
|
*
|
|
* Extend area map of @chunk so that it can accomodate an allocation.
|
|
* A single allocation can split an area into three areas, so this
|
|
* function makes sure that @chunk->map has at least two extra slots.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired
|
|
* if area map is extended.
|
|
*
|
|
* RETURNS:
|
|
* 0 if noop, 1 if successfully extended, -errno on failure.
|
|
*/
|
|
static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
|
|
{
|
|
int new_alloc;
|
|
int *new;
|
|
size_t size;
|
|
|
|
/* has enough? */
|
|
if (chunk->map_alloc >= chunk->map_used + 2)
|
|
return 0;
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
|
|
new_alloc = PCPU_DFL_MAP_ALLOC;
|
|
while (new_alloc < chunk->map_used + 2)
|
|
new_alloc *= 2;
|
|
|
|
new = pcpu_mem_alloc(new_alloc * sizeof(new[0]));
|
|
if (!new) {
|
|
spin_lock_irq(&pcpu_lock);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Acquire pcpu_lock and switch to new area map. Only free
|
|
* could have happened inbetween, so map_used couldn't have
|
|
* grown.
|
|
*/
|
|
spin_lock_irq(&pcpu_lock);
|
|
BUG_ON(new_alloc < chunk->map_used + 2);
|
|
|
|
size = chunk->map_alloc * sizeof(chunk->map[0]);
|
|
memcpy(new, chunk->map, size);
|
|
|
|
/*
|
|
* map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is
|
|
* one of the first chunks and still using static map.
|
|
*/
|
|
if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC)
|
|
pcpu_mem_free(chunk->map, size);
|
|
|
|
chunk->map_alloc = new_alloc;
|
|
chunk->map = new;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* pcpu_split_block - split a map block
|
|
* @chunk: chunk of interest
|
|
* @i: index of map block to split
|
|
* @head: head size in bytes (can be 0)
|
|
* @tail: tail size in bytes (can be 0)
|
|
*
|
|
* Split the @i'th map block into two or three blocks. If @head is
|
|
* non-zero, @head bytes block is inserted before block @i moving it
|
|
* to @i+1 and reducing its size by @head bytes.
|
|
*
|
|
* If @tail is non-zero, the target block, which can be @i or @i+1
|
|
* depending on @head, is reduced by @tail bytes and @tail byte block
|
|
* is inserted after the target block.
|
|
*
|
|
* @chunk->map must have enough free slots to accomodate the split.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*/
|
|
static void pcpu_split_block(struct pcpu_chunk *chunk, int i,
|
|
int head, int tail)
|
|
{
|
|
int nr_extra = !!head + !!tail;
|
|
|
|
BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra);
|
|
|
|
/* insert new subblocks */
|
|
memmove(&chunk->map[i + nr_extra], &chunk->map[i],
|
|
sizeof(chunk->map[0]) * (chunk->map_used - i));
|
|
chunk->map_used += nr_extra;
|
|
|
|
if (head) {
|
|
chunk->map[i + 1] = chunk->map[i] - head;
|
|
chunk->map[i++] = head;
|
|
}
|
|
if (tail) {
|
|
chunk->map[i++] -= tail;
|
|
chunk->map[i] = tail;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc_area - allocate area from a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @size: wanted size in bytes
|
|
* @align: wanted align
|
|
*
|
|
* Try to allocate @size bytes area aligned at @align from @chunk.
|
|
* Note that this function only allocates the offset. It doesn't
|
|
* populate or map the area.
|
|
*
|
|
* @chunk->map must have at least two free slots.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*
|
|
* RETURNS:
|
|
* Allocated offset in @chunk on success, -1 if no matching area is
|
|
* found.
|
|
*/
|
|
static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
|
|
{
|
|
int oslot = pcpu_chunk_slot(chunk);
|
|
int max_contig = 0;
|
|
int i, off;
|
|
|
|
for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
|
|
bool is_last = i + 1 == chunk->map_used;
|
|
int head, tail;
|
|
|
|
/* extra for alignment requirement */
|
|
head = ALIGN(off, align) - off;
|
|
BUG_ON(i == 0 && head != 0);
|
|
|
|
if (chunk->map[i] < 0)
|
|
continue;
|
|
if (chunk->map[i] < head + size) {
|
|
max_contig = max(chunk->map[i], max_contig);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If head is small or the previous block is free,
|
|
* merge'em. Note that 'small' is defined as smaller
|
|
* than sizeof(int), which is very small but isn't too
|
|
* uncommon for percpu allocations.
|
|
*/
|
|
if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
|
|
if (chunk->map[i - 1] > 0)
|
|
chunk->map[i - 1] += head;
|
|
else {
|
|
chunk->map[i - 1] -= head;
|
|
chunk->free_size -= head;
|
|
}
|
|
chunk->map[i] -= head;
|
|
off += head;
|
|
head = 0;
|
|
}
|
|
|
|
/* if tail is small, just keep it around */
|
|
tail = chunk->map[i] - head - size;
|
|
if (tail < sizeof(int))
|
|
tail = 0;
|
|
|
|
/* split if warranted */
|
|
if (head || tail) {
|
|
pcpu_split_block(chunk, i, head, tail);
|
|
if (head) {
|
|
i++;
|
|
off += head;
|
|
max_contig = max(chunk->map[i - 1], max_contig);
|
|
}
|
|
if (tail)
|
|
max_contig = max(chunk->map[i + 1], max_contig);
|
|
}
|
|
|
|
/* update hint and mark allocated */
|
|
if (is_last)
|
|
chunk->contig_hint = max_contig; /* fully scanned */
|
|
else
|
|
chunk->contig_hint = max(chunk->contig_hint,
|
|
max_contig);
|
|
|
|
chunk->free_size -= chunk->map[i];
|
|
chunk->map[i] = -chunk->map[i];
|
|
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
return off;
|
|
}
|
|
|
|
chunk->contig_hint = max_contig; /* fully scanned */
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
|
|
/* tell the upper layer that this chunk has no matching area */
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* pcpu_free_area - free area to a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @freeme: offset of area to free
|
|
*
|
|
* Free area starting from @freeme to @chunk. Note that this function
|
|
* only modifies the allocation map. It doesn't depopulate or unmap
|
|
* the area.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*/
|
|
static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
|
|
{
|
|
int oslot = pcpu_chunk_slot(chunk);
|
|
int i, off;
|
|
|
|
for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
|
|
if (off == freeme)
|
|
break;
|
|
BUG_ON(off != freeme);
|
|
BUG_ON(chunk->map[i] > 0);
|
|
|
|
chunk->map[i] = -chunk->map[i];
|
|
chunk->free_size += chunk->map[i];
|
|
|
|
/* merge with previous? */
|
|
if (i > 0 && chunk->map[i - 1] >= 0) {
|
|
chunk->map[i - 1] += chunk->map[i];
|
|
chunk->map_used--;
|
|
memmove(&chunk->map[i], &chunk->map[i + 1],
|
|
(chunk->map_used - i) * sizeof(chunk->map[0]));
|
|
i--;
|
|
}
|
|
/* merge with next? */
|
|
if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
|
|
chunk->map[i] += chunk->map[i + 1];
|
|
chunk->map_used--;
|
|
memmove(&chunk->map[i + 1], &chunk->map[i + 2],
|
|
(chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
|
|
}
|
|
|
|
chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
}
|
|
|
|
/**
|
|
* pcpu_unmap - unmap pages out of a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @page_start: page index of the first page to unmap
|
|
* @page_end: page index of the last page to unmap + 1
|
|
* @flush_tlb: whether to flush tlb or not
|
|
*
|
|
* For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
|
|
* If @flush is true, vcache is flushed before unmapping and tlb
|
|
* after.
|
|
*/
|
|
static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
|
|
bool flush_tlb)
|
|
{
|
|
unsigned int last = num_possible_cpus() - 1;
|
|
unsigned int cpu;
|
|
|
|
/* unmap must not be done on immutable chunk */
|
|
WARN_ON(chunk->immutable);
|
|
|
|
/*
|
|
* Each flushing trial can be very expensive, issue flush on
|
|
* the whole region at once rather than doing it for each cpu.
|
|
* This could be an overkill but is more scalable.
|
|
*/
|
|
flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
|
|
pcpu_chunk_addr(chunk, last, page_end));
|
|
|
|
for_each_possible_cpu(cpu)
|
|
unmap_kernel_range_noflush(
|
|
pcpu_chunk_addr(chunk, cpu, page_start),
|
|
(page_end - page_start) << PAGE_SHIFT);
|
|
|
|
/* ditto as flush_cache_vunmap() */
|
|
if (flush_tlb)
|
|
flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
|
|
pcpu_chunk_addr(chunk, last, page_end));
|
|
}
|
|
|
|
static int __pcpu_map_pages(unsigned long addr, struct page **pages,
|
|
int nr_pages)
|
|
{
|
|
return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
|
|
PAGE_KERNEL, pages);
|
|
}
|
|
|
|
/**
|
|
* pcpu_map - map pages into a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @page_start: page index of the first page to map
|
|
* @page_end: page index of the last page to map + 1
|
|
*
|
|
* For each cpu, map pages [@page_start,@page_end) into @chunk.
|
|
* vcache is flushed afterwards.
|
|
*/
|
|
static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
|
|
{
|
|
unsigned int last = num_possible_cpus() - 1;
|
|
unsigned int cpu;
|
|
int err;
|
|
|
|
/* map must not be done on immutable chunk */
|
|
WARN_ON(chunk->immutable);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
|
|
pcpu_chunk_pagep(chunk, cpu, page_start),
|
|
page_end - page_start);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
/* flush at once, please read comments in pcpu_unmap() */
|
|
flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start),
|
|
pcpu_chunk_addr(chunk, last, page_end));
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
|
|
* @chunk: chunk to depopulate
|
|
* @off: offset to the area to depopulate
|
|
* @size: size of the area to depopulate in bytes
|
|
* @flush: whether to flush cache and tlb or not
|
|
*
|
|
* For each cpu, depopulate and unmap pages [@page_start,@page_end)
|
|
* from @chunk. If @flush is true, vcache is flushed before unmapping
|
|
* and tlb after.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_alloc_mutex.
|
|
*/
|
|
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
|
|
bool flush)
|
|
{
|
|
int page_start = PFN_DOWN(off);
|
|
int page_end = PFN_UP(off + size);
|
|
int unmap_start = -1;
|
|
int uninitialized_var(unmap_end);
|
|
unsigned int cpu;
|
|
int i;
|
|
|
|
for (i = page_start; i < page_end; i++) {
|
|
for_each_possible_cpu(cpu) {
|
|
struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
|
|
|
|
if (!*pagep)
|
|
continue;
|
|
|
|
__free_page(*pagep);
|
|
|
|
/*
|
|
* If it's partial depopulation, it might get
|
|
* populated or depopulated again. Mark the
|
|
* page gone.
|
|
*/
|
|
*pagep = NULL;
|
|
|
|
unmap_start = unmap_start < 0 ? i : unmap_start;
|
|
unmap_end = i + 1;
|
|
}
|
|
}
|
|
|
|
if (unmap_start >= 0)
|
|
pcpu_unmap(chunk, unmap_start, unmap_end, flush);
|
|
}
|
|
|
|
/**
|
|
* pcpu_populate_chunk - populate and map an area of a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @off: offset to the area to populate
|
|
* @size: size of the area to populate in bytes
|
|
*
|
|
* For each cpu, populate and map pages [@page_start,@page_end) into
|
|
* @chunk. The area is cleared on return.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_alloc_mutex, does GFP_KERNEL allocation.
|
|
*/
|
|
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
|
|
{
|
|
const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
|
|
int page_start = PFN_DOWN(off);
|
|
int page_end = PFN_UP(off + size);
|
|
int map_start = -1;
|
|
int uninitialized_var(map_end);
|
|
unsigned int cpu;
|
|
int i;
|
|
|
|
for (i = page_start; i < page_end; i++) {
|
|
if (pcpu_chunk_page_occupied(chunk, i)) {
|
|
if (map_start >= 0) {
|
|
if (pcpu_map(chunk, map_start, map_end))
|
|
goto err;
|
|
map_start = -1;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
map_start = map_start < 0 ? i : map_start;
|
|
map_end = i + 1;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
|
|
|
|
*pagep = alloc_pages_node(cpu_to_node(cpu),
|
|
alloc_mask, 0);
|
|
if (!*pagep)
|
|
goto err;
|
|
pcpu_set_page_chunk(*pagep, chunk);
|
|
}
|
|
}
|
|
|
|
if (map_start >= 0 && pcpu_map(chunk, map_start, map_end))
|
|
goto err;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0,
|
|
size);
|
|
|
|
return 0;
|
|
err:
|
|
/* likely under heavy memory pressure, give memory back */
|
|
pcpu_depopulate_chunk(chunk, off, size, true);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void free_pcpu_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
if (!chunk)
|
|
return;
|
|
if (chunk->vm)
|
|
free_vm_area(chunk->vm);
|
|
pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
|
|
kfree(chunk);
|
|
}
|
|
|
|
static struct pcpu_chunk *alloc_pcpu_chunk(void)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
|
|
chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
|
|
if (!chunk)
|
|
return NULL;
|
|
|
|
chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
|
|
chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
|
|
chunk->map[chunk->map_used++] = pcpu_unit_size;
|
|
chunk->page = chunk->page_ar;
|
|
|
|
chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL);
|
|
if (!chunk->vm) {
|
|
free_pcpu_chunk(chunk);
|
|
return NULL;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&chunk->list);
|
|
chunk->free_size = pcpu_unit_size;
|
|
chunk->contig_hint = pcpu_unit_size;
|
|
|
|
return chunk;
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc - the percpu allocator
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
* @reserved: allocate from the reserved chunk if available
|
|
*
|
|
* Allocate percpu area of @size bytes aligned at @align.
|
|
*
|
|
* CONTEXT:
|
|
* Does GFP_KERNEL allocation.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
static void *pcpu_alloc(size_t size, size_t align, bool reserved)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
int slot, off;
|
|
|
|
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
|
|
WARN(true, "illegal size (%zu) or align (%zu) for "
|
|
"percpu allocation\n", size, align);
|
|
return NULL;
|
|
}
|
|
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
spin_lock_irq(&pcpu_lock);
|
|
|
|
/* serve reserved allocations from the reserved chunk if available */
|
|
if (reserved && pcpu_reserved_chunk) {
|
|
chunk = pcpu_reserved_chunk;
|
|
if (size > chunk->contig_hint ||
|
|
pcpu_extend_area_map(chunk) < 0)
|
|
goto fail_unlock;
|
|
off = pcpu_alloc_area(chunk, size, align);
|
|
if (off >= 0)
|
|
goto area_found;
|
|
goto fail_unlock;
|
|
}
|
|
|
|
restart:
|
|
/* search through normal chunks */
|
|
for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
|
|
list_for_each_entry(chunk, &pcpu_slot[slot], list) {
|
|
if (size > chunk->contig_hint)
|
|
continue;
|
|
|
|
switch (pcpu_extend_area_map(chunk)) {
|
|
case 0:
|
|
break;
|
|
case 1:
|
|
goto restart; /* pcpu_lock dropped, restart */
|
|
default:
|
|
goto fail_unlock;
|
|
}
|
|
|
|
off = pcpu_alloc_area(chunk, size, align);
|
|
if (off >= 0)
|
|
goto area_found;
|
|
}
|
|
}
|
|
|
|
/* hmmm... no space left, create a new chunk */
|
|
spin_unlock_irq(&pcpu_lock);
|
|
|
|
chunk = alloc_pcpu_chunk();
|
|
if (!chunk)
|
|
goto fail_unlock_mutex;
|
|
|
|
spin_lock_irq(&pcpu_lock);
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
goto restart;
|
|
|
|
area_found:
|
|
spin_unlock_irq(&pcpu_lock);
|
|
|
|
/* populate, map and clear the area */
|
|
if (pcpu_populate_chunk(chunk, off, size)) {
|
|
spin_lock_irq(&pcpu_lock);
|
|
pcpu_free_area(chunk, off);
|
|
goto fail_unlock;
|
|
}
|
|
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
|
|
return __addr_to_pcpu_ptr(chunk->vm->addr + off);
|
|
|
|
fail_unlock:
|
|
spin_unlock_irq(&pcpu_lock);
|
|
fail_unlock_mutex:
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* __alloc_percpu - allocate dynamic percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Allocate percpu area of @size bytes aligned at @align. Might
|
|
* sleep. Might trigger writeouts.
|
|
*
|
|
* CONTEXT:
|
|
* Does GFP_KERNEL allocation.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void *__alloc_percpu(size_t size, size_t align)
|
|
{
|
|
return pcpu_alloc(size, align, false);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__alloc_percpu);
|
|
|
|
/**
|
|
* __alloc_reserved_percpu - allocate reserved percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Allocate percpu area of @size bytes aligned at @align from reserved
|
|
* percpu area if arch has set it up; otherwise, allocation is served
|
|
* from the same dynamic area. Might sleep. Might trigger writeouts.
|
|
*
|
|
* CONTEXT:
|
|
* Does GFP_KERNEL allocation.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void *__alloc_reserved_percpu(size_t size, size_t align)
|
|
{
|
|
return pcpu_alloc(size, align, true);
|
|
}
|
|
|
|
/**
|
|
* pcpu_reclaim - reclaim fully free chunks, workqueue function
|
|
* @work: unused
|
|
*
|
|
* Reclaim all fully free chunks except for the first one.
|
|
*
|
|
* CONTEXT:
|
|
* workqueue context.
|
|
*/
|
|
static void pcpu_reclaim(struct work_struct *work)
|
|
{
|
|
LIST_HEAD(todo);
|
|
struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
|
|
struct pcpu_chunk *chunk, *next;
|
|
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
spin_lock_irq(&pcpu_lock);
|
|
|
|
list_for_each_entry_safe(chunk, next, head, list) {
|
|
WARN_ON(chunk->immutable);
|
|
|
|
/* spare the first one */
|
|
if (chunk == list_first_entry(head, struct pcpu_chunk, list))
|
|
continue;
|
|
|
|
list_move(&chunk->list, &todo);
|
|
}
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
|
|
list_for_each_entry_safe(chunk, next, &todo, list) {
|
|
pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false);
|
|
free_pcpu_chunk(chunk);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* free_percpu - free percpu area
|
|
* @ptr: pointer to area to free
|
|
*
|
|
* Free percpu area @ptr.
|
|
*
|
|
* CONTEXT:
|
|
* Can be called from atomic context.
|
|
*/
|
|
void free_percpu(void *ptr)
|
|
{
|
|
void *addr = __pcpu_ptr_to_addr(ptr);
|
|
struct pcpu_chunk *chunk;
|
|
unsigned long flags;
|
|
int off;
|
|
|
|
if (!ptr)
|
|
return;
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
|
|
chunk = pcpu_chunk_addr_search(addr);
|
|
off = addr - chunk->vm->addr;
|
|
|
|
pcpu_free_area(chunk, off);
|
|
|
|
/* if there are more than one fully free chunks, wake up grim reaper */
|
|
if (chunk->free_size == pcpu_unit_size) {
|
|
struct pcpu_chunk *pos;
|
|
|
|
list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
|
|
if (pos != chunk) {
|
|
schedule_work(&pcpu_reclaim_work);
|
|
break;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(free_percpu);
|
|
|
|
/**
|
|
* pcpu_setup_first_chunk - initialize the first percpu chunk
|
|
* @get_page_fn: callback to fetch page pointer
|
|
* @static_size: the size of static percpu area in bytes
|
|
* @reserved_size: the size of reserved percpu area in bytes, 0 for none
|
|
* @dyn_size: free size for dynamic allocation in bytes, -1 for auto
|
|
* @unit_size: unit size in bytes, must be multiple of PAGE_SIZE
|
|
* @base_addr: mapped address
|
|
*
|
|
* Initialize the first percpu chunk which contains the kernel static
|
|
* perpcu area. This function is to be called from arch percpu area
|
|
* setup path.
|
|
*
|
|
* @get_page_fn() should return pointer to percpu page given cpu
|
|
* number and page number. It should at least return enough pages to
|
|
* cover the static area. The returned pages for static area should
|
|
* have been initialized with valid data. It can also return pages
|
|
* after the static area. NULL return indicates end of pages for the
|
|
* cpu. Note that @get_page_fn() must return the same number of pages
|
|
* for all cpus.
|
|
*
|
|
* @reserved_size, if non-zero, specifies the amount of bytes to
|
|
* reserve after the static area in the first chunk. This reserves
|
|
* the first chunk such that it's available only through reserved
|
|
* percpu allocation. This is primarily used to serve module percpu
|
|
* static areas on architectures where the addressing model has
|
|
* limited offset range for symbol relocations to guarantee module
|
|
* percpu symbols fall inside the relocatable range.
|
|
*
|
|
* @dyn_size, if non-negative, determines the number of bytes
|
|
* available for dynamic allocation in the first chunk. Specifying
|
|
* non-negative value makes percpu leave alone the area beyond
|
|
* @static_size + @reserved_size + @dyn_size.
|
|
*
|
|
* @unit_size specifies unit size and must be aligned to PAGE_SIZE and
|
|
* equal to or larger than @static_size + @reserved_size + if
|
|
* non-negative, @dyn_size.
|
|
*
|
|
* The caller should have mapped the first chunk at @base_addr and
|
|
* copied static data to each unit.
|
|
*
|
|
* If the first chunk ends up with both reserved and dynamic areas, it
|
|
* is served by two chunks - one to serve the core static and reserved
|
|
* areas and the other for the dynamic area. They share the same vm
|
|
* and page map but uses different area allocation map to stay away
|
|
* from each other. The latter chunk is circulated in the chunk slots
|
|
* and available for dynamic allocation like any other chunks.
|
|
*
|
|
* RETURNS:
|
|
* The determined pcpu_unit_size which can be used to initialize
|
|
* percpu access.
|
|
*/
|
|
size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
|
|
size_t static_size, size_t reserved_size,
|
|
ssize_t dyn_size, size_t unit_size,
|
|
void *base_addr)
|
|
{
|
|
static struct vm_struct first_vm;
|
|
static int smap[2], dmap[2];
|
|
size_t size_sum = static_size + reserved_size +
|
|
(dyn_size >= 0 ? dyn_size : 0);
|
|
struct pcpu_chunk *schunk, *dchunk = NULL;
|
|
unsigned int cpu;
|
|
int i, nr_pages;
|
|
|
|
/* santiy checks */
|
|
BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
|
|
ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
|
|
BUG_ON(!static_size);
|
|
BUG_ON(!base_addr);
|
|
BUG_ON(unit_size < size_sum);
|
|
BUG_ON(unit_size & ~PAGE_MASK);
|
|
BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE);
|
|
|
|
pcpu_unit_pages = unit_size >> PAGE_SHIFT;
|
|
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
|
|
pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
|
|
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
|
|
+ num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *);
|
|
|
|
if (dyn_size < 0)
|
|
dyn_size = pcpu_unit_size - static_size - reserved_size;
|
|
|
|
first_vm.flags = VM_ALLOC;
|
|
first_vm.size = pcpu_chunk_size;
|
|
first_vm.addr = base_addr;
|
|
|
|
/*
|
|
* Allocate chunk slots. The additional last slot is for
|
|
* empty chunks.
|
|
*/
|
|
pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
|
|
pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
|
|
for (i = 0; i < pcpu_nr_slots; i++)
|
|
INIT_LIST_HEAD(&pcpu_slot[i]);
|
|
|
|
/*
|
|
* Initialize static chunk. If reserved_size is zero, the
|
|
* static chunk covers static area + dynamic allocation area
|
|
* in the first chunk. If reserved_size is not zero, it
|
|
* covers static area + reserved area (mostly used for module
|
|
* static percpu allocation).
|
|
*/
|
|
schunk = alloc_bootmem(pcpu_chunk_struct_size);
|
|
INIT_LIST_HEAD(&schunk->list);
|
|
schunk->vm = &first_vm;
|
|
schunk->map = smap;
|
|
schunk->map_alloc = ARRAY_SIZE(smap);
|
|
schunk->page = schunk->page_ar;
|
|
schunk->immutable = true;
|
|
|
|
if (reserved_size) {
|
|
schunk->free_size = reserved_size;
|
|
pcpu_reserved_chunk = schunk;
|
|
pcpu_reserved_chunk_limit = static_size + reserved_size;
|
|
} else {
|
|
schunk->free_size = dyn_size;
|
|
dyn_size = 0; /* dynamic area covered */
|
|
}
|
|
schunk->contig_hint = schunk->free_size;
|
|
|
|
schunk->map[schunk->map_used++] = -static_size;
|
|
if (schunk->free_size)
|
|
schunk->map[schunk->map_used++] = schunk->free_size;
|
|
|
|
/* init dynamic chunk if necessary */
|
|
if (dyn_size) {
|
|
dchunk = alloc_bootmem(sizeof(struct pcpu_chunk));
|
|
INIT_LIST_HEAD(&dchunk->list);
|
|
dchunk->vm = &first_vm;
|
|
dchunk->map = dmap;
|
|
dchunk->map_alloc = ARRAY_SIZE(dmap);
|
|
dchunk->page = schunk->page_ar; /* share page map with schunk */
|
|
dchunk->immutable = true;
|
|
|
|
dchunk->contig_hint = dchunk->free_size = dyn_size;
|
|
dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
|
|
dchunk->map[dchunk->map_used++] = dchunk->free_size;
|
|
}
|
|
|
|
/* assign pages */
|
|
nr_pages = -1;
|
|
for_each_possible_cpu(cpu) {
|
|
for (i = 0; i < pcpu_unit_pages; i++) {
|
|
struct page *page = get_page_fn(cpu, i);
|
|
|
|
if (!page)
|
|
break;
|
|
*pcpu_chunk_pagep(schunk, cpu, i) = page;
|
|
}
|
|
|
|
BUG_ON(i < PFN_UP(static_size));
|
|
|
|
if (nr_pages < 0)
|
|
nr_pages = i;
|
|
else
|
|
BUG_ON(nr_pages != i);
|
|
}
|
|
|
|
/* link the first chunk in */
|
|
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);
|
|
return pcpu_unit_size;
|
|
}
|
|
|
|
static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size,
|
|
ssize_t *dyn_sizep)
|
|
{
|
|
size_t size_sum;
|
|
|
|
size_sum = PFN_ALIGN(static_size + reserved_size +
|
|
(*dyn_sizep >= 0 ? *dyn_sizep : 0));
|
|
if (*dyn_sizep != 0)
|
|
*dyn_sizep = size_sum - static_size - reserved_size;
|
|
|
|
return size_sum;
|
|
}
|
|
|
|
/*
|
|
* Embedding first chunk setup helper.
|
|
*/
|
|
static void *pcpue_ptr __initdata;
|
|
static size_t pcpue_size __initdata;
|
|
static size_t pcpue_unit_size __initdata;
|
|
|
|
static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
|
|
{
|
|
size_t off = (size_t)pageno << PAGE_SHIFT;
|
|
|
|
if (off >= pcpue_size)
|
|
return NULL;
|
|
|
|
return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off);
|
|
}
|
|
|
|
/**
|
|
* pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
|
|
* @static_size: the size of static percpu area in bytes
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @dyn_size: free size for dynamic allocation in bytes, -1 for auto
|
|
*
|
|
* This is a helper to ease setting up embedded first percpu chunk and
|
|
* can be called where pcpu_setup_first_chunk() is expected.
|
|
*
|
|
* If this function is used to setup the first chunk, it is allocated
|
|
* as a contiguous area using bootmem allocator and used as-is without
|
|
* being mapped into vmalloc area. This enables the first chunk to
|
|
* piggy back on the linear physical mapping which often uses larger
|
|
* page size.
|
|
*
|
|
* When @dyn_size is positive, dynamic area might be larger than
|
|
* specified to fill page alignment. When @dyn_size is auto,
|
|
* @dyn_size is just big enough to fill page alignment after static
|
|
* and reserved areas.
|
|
*
|
|
* If the needed size is smaller than the minimum or specified unit
|
|
* size, the leftover is returned to the bootmem allocator.
|
|
*
|
|
* RETURNS:
|
|
* The determined pcpu_unit_size which can be used to initialize
|
|
* percpu access on success, -errno on failure.
|
|
*/
|
|
ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
|
|
ssize_t dyn_size)
|
|
{
|
|
size_t chunk_size;
|
|
unsigned int cpu;
|
|
|
|
/* determine parameters and allocate */
|
|
pcpue_size = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
|
|
|
|
pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
|
|
chunk_size = pcpue_unit_size * num_possible_cpus();
|
|
|
|
pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
|
|
__pa(MAX_DMA_ADDRESS));
|
|
if (!pcpue_ptr) {
|
|
pr_warning("PERCPU: failed to allocate %zu bytes for "
|
|
"embedding\n", chunk_size);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* return the leftover and copy */
|
|
for_each_possible_cpu(cpu) {
|
|
void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
|
|
|
|
free_bootmem(__pa(ptr + pcpue_size),
|
|
pcpue_unit_size - pcpue_size);
|
|
memcpy(ptr, __per_cpu_load, static_size);
|
|
}
|
|
|
|
/* we're ready, commit */
|
|
pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n",
|
|
pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size);
|
|
|
|
return pcpu_setup_first_chunk(pcpue_get_page, static_size,
|
|
reserved_size, dyn_size,
|
|
pcpue_unit_size, pcpue_ptr);
|
|
}
|
|
|
|
/*
|
|
* 4k page first chunk setup helper.
|
|
*/
|
|
static struct page **pcpu4k_pages __initdata;
|
|
static int pcpu4k_unit_pages __initdata;
|
|
|
|
static struct page * __init pcpu4k_get_page(unsigned int cpu, int pageno)
|
|
{
|
|
if (pageno < pcpu4k_unit_pages)
|
|
return pcpu4k_pages[cpu * pcpu4k_unit_pages + pageno];
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* pcpu_4k_first_chunk - map the first chunk using PAGE_SIZE pages
|
|
* @static_size: the size of static percpu area in bytes
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
|
|
* @free_fn: funtion to free percpu page, always called with PAGE_SIZE
|
|
* @populate_pte_fn: function to populate pte
|
|
*
|
|
* This is a helper to ease setting up embedded first percpu chunk and
|
|
* can be called where pcpu_setup_first_chunk() is expected.
|
|
*
|
|
* This is the basic allocator. Static percpu area is allocated
|
|
* page-by-page into vmalloc area.
|
|
*
|
|
* RETURNS:
|
|
* The determined pcpu_unit_size which can be used to initialize
|
|
* percpu access on success, -errno on failure.
|
|
*/
|
|
ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
|
|
pcpu_fc_alloc_fn_t alloc_fn,
|
|
pcpu_fc_free_fn_t free_fn,
|
|
pcpu_fc_populate_pte_fn_t populate_pte_fn)
|
|
{
|
|
static struct vm_struct vm;
|
|
size_t pages_size;
|
|
unsigned int cpu;
|
|
int i, j;
|
|
ssize_t ret;
|
|
|
|
pcpu4k_unit_pages = PFN_UP(max_t(size_t, static_size + reserved_size,
|
|
PCPU_MIN_UNIT_SIZE));
|
|
|
|
/* unaligned allocations can't be freed, round up to page size */
|
|
pages_size = PFN_ALIGN(pcpu4k_unit_pages * num_possible_cpus() *
|
|
sizeof(pcpu4k_pages[0]));
|
|
pcpu4k_pages = alloc_bootmem(pages_size);
|
|
|
|
/* allocate pages */
|
|
j = 0;
|
|
for_each_possible_cpu(cpu)
|
|
for (i = 0; i < pcpu4k_unit_pages; i++) {
|
|
void *ptr;
|
|
|
|
ptr = alloc_fn(cpu, PAGE_SIZE);
|
|
if (!ptr) {
|
|
pr_warning("PERCPU: failed to allocate "
|
|
"4k page for cpu%u\n", cpu);
|
|
goto enomem;
|
|
}
|
|
pcpu4k_pages[j++] = virt_to_page(ptr);
|
|
}
|
|
|
|
/* allocate vm area, map the pages and copy static data */
|
|
vm.flags = VM_ALLOC;
|
|
vm.size = num_possible_cpus() * pcpu4k_unit_pages << PAGE_SHIFT;
|
|
vm_area_register_early(&vm, PAGE_SIZE);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
unsigned long unit_addr = (unsigned long)vm.addr +
|
|
(cpu * pcpu4k_unit_pages << PAGE_SHIFT);
|
|
|
|
for (i = 0; i < pcpu4k_unit_pages; i++)
|
|
populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
|
|
|
|
/* pte already populated, the following shouldn't fail */
|
|
ret = __pcpu_map_pages(unit_addr,
|
|
&pcpu4k_pages[cpu * pcpu4k_unit_pages],
|
|
pcpu4k_unit_pages);
|
|
if (ret < 0)
|
|
panic("failed to map percpu area, err=%zd\n", ret);
|
|
|
|
/*
|
|
* FIXME: Archs with virtual cache should flush local
|
|
* cache for the linear mapping here - something
|
|
* equivalent to flush_cache_vmap() on the local cpu.
|
|
* flush_cache_vmap() can't be used as most supporting
|
|
* data structures are not set up yet.
|
|
*/
|
|
|
|
/* copy static data */
|
|
memcpy((void *)unit_addr, __per_cpu_load, static_size);
|
|
}
|
|
|
|
/* we're ready, commit */
|
|
pr_info("PERCPU: %d 4k pages per cpu, static data %zu bytes\n",
|
|
pcpu4k_unit_pages, static_size);
|
|
|
|
ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
|
|
reserved_size, -1,
|
|
pcpu4k_unit_pages << PAGE_SHIFT, vm.addr);
|
|
goto out_free_ar;
|
|
|
|
enomem:
|
|
while (--j >= 0)
|
|
free_fn(page_address(pcpu4k_pages[j]), PAGE_SIZE);
|
|
ret = -ENOMEM;
|
|
out_free_ar:
|
|
free_bootmem(__pa(pcpu4k_pages), pages_size);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Large page remapping first chunk setup helper
|
|
*/
|
|
#ifdef CONFIG_NEED_MULTIPLE_NODES
|
|
struct pcpul_ent {
|
|
unsigned int cpu;
|
|
void *ptr;
|
|
};
|
|
|
|
static size_t pcpul_size;
|
|
static size_t pcpul_unit_size;
|
|
static struct pcpul_ent *pcpul_map;
|
|
static struct vm_struct pcpul_vm;
|
|
|
|
static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
|
|
{
|
|
size_t off = (size_t)pageno << PAGE_SHIFT;
|
|
|
|
if (off >= pcpul_size)
|
|
return NULL;
|
|
|
|
return virt_to_page(pcpul_map[cpu].ptr + off);
|
|
}
|
|
|
|
/**
|
|
* pcpu_lpage_first_chunk - remap the first percpu chunk using large page
|
|
* @static_size: the size of static percpu area in bytes
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @dyn_size: free size for dynamic allocation in bytes, -1 for auto
|
|
* @lpage_size: the size of a large page
|
|
* @alloc_fn: function to allocate percpu lpage, always called with lpage_size
|
|
* @free_fn: function to free percpu memory, @size <= lpage_size
|
|
* @map_fn: function to map percpu lpage, always called with lpage_size
|
|
*
|
|
* This allocator uses large page as unit. A large page is allocated
|
|
* for each cpu and each is remapped into vmalloc area using large
|
|
* page mapping. As large page can be quite large, only part of it is
|
|
* used for the first chunk. Unused part is returned to the bootmem
|
|
* allocator.
|
|
*
|
|
* So, the large pages are mapped twice - once to the physical mapping
|
|
* and to the vmalloc area for the first percpu chunk. The double
|
|
* mapping does add one more large TLB entry pressure but still is
|
|
* much better than only using 4k mappings while still being NUMA
|
|
* friendly.
|
|
*
|
|
* RETURNS:
|
|
* The determined pcpu_unit_size which can be used to initialize
|
|
* percpu access on success, -errno on failure.
|
|
*/
|
|
ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size,
|
|
ssize_t dyn_size, size_t lpage_size,
|
|
pcpu_fc_alloc_fn_t alloc_fn,
|
|
pcpu_fc_free_fn_t free_fn,
|
|
pcpu_fc_map_fn_t map_fn)
|
|
{
|
|
size_t size_sum;
|
|
size_t map_size;
|
|
unsigned int cpu;
|
|
int i, j;
|
|
ssize_t ret;
|
|
|
|
/*
|
|
* Currently supports only single page. Supporting multiple
|
|
* pages won't be too difficult if it ever becomes necessary.
|
|
*/
|
|
size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
|
|
|
|
pcpul_unit_size = lpage_size;
|
|
pcpul_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
|
|
if (pcpul_size > pcpul_unit_size) {
|
|
pr_warning("PERCPU: static data is larger than large page, "
|
|
"can't use large page\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* allocate pointer array and alloc large pages */
|
|
map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0]));
|
|
pcpul_map = alloc_bootmem(map_size);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
void *ptr;
|
|
|
|
ptr = alloc_fn(cpu, lpage_size);
|
|
if (!ptr) {
|
|
pr_warning("PERCPU: failed to allocate large page "
|
|
"for cpu%u\n", cpu);
|
|
goto enomem;
|
|
}
|
|
|
|
/*
|
|
* Only use pcpul_size bytes and give back the rest.
|
|
*
|
|
* Ingo: The lpage_size up-rounding bootmem is needed
|
|
* to make sure the partial lpage is still fully RAM -
|
|
* it's not well-specified to have a incompatible area
|
|
* (unmapped RAM, device memory, etc.) in that hole.
|
|
*/
|
|
free_fn(ptr + pcpul_size, lpage_size - pcpul_size);
|
|
|
|
pcpul_map[cpu].cpu = cpu;
|
|
pcpul_map[cpu].ptr = ptr;
|
|
|
|
memcpy(ptr, __per_cpu_load, static_size);
|
|
}
|
|
|
|
/* allocate address and map */
|
|
pcpul_vm.flags = VM_ALLOC;
|
|
pcpul_vm.size = num_possible_cpus() * pcpul_unit_size;
|
|
vm_area_register_early(&pcpul_vm, pcpul_unit_size);
|
|
|
|
for_each_possible_cpu(cpu)
|
|
map_fn(pcpul_map[cpu].ptr, pcpul_unit_size,
|
|
pcpul_vm.addr + cpu * pcpul_unit_size);
|
|
|
|
/* we're ready, commit */
|
|
pr_info("PERCPU: Remapped at %p with large pages, static data "
|
|
"%zu bytes\n", pcpul_vm.addr, static_size);
|
|
|
|
ret = pcpu_setup_first_chunk(pcpul_get_page, static_size,
|
|
reserved_size, dyn_size, pcpul_unit_size,
|
|
pcpul_vm.addr);
|
|
|
|
/* sort pcpul_map array for pcpu_lpage_remapped() */
|
|
for (i = 0; i < num_possible_cpus() - 1; i++)
|
|
for (j = i + 1; j < num_possible_cpus(); j++)
|
|
if (pcpul_map[i].ptr > pcpul_map[j].ptr) {
|
|
struct pcpul_ent tmp = pcpul_map[i];
|
|
pcpul_map[i] = pcpul_map[j];
|
|
pcpul_map[j] = tmp;
|
|
}
|
|
|
|
return ret;
|
|
|
|
enomem:
|
|
for_each_possible_cpu(cpu)
|
|
if (pcpul_map[cpu].ptr)
|
|
free_fn(pcpul_map[cpu].ptr, pcpul_size);
|
|
free_bootmem(__pa(pcpul_map), map_size);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/**
|
|
* pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area
|
|
* @kaddr: the kernel address in question
|
|
*
|
|
* Determine whether @kaddr falls in the pcpul recycled area. This is
|
|
* used by pageattr to detect VM aliases and break up the pcpu large
|
|
* page mapping such that the same physical page is not mapped under
|
|
* different attributes.
|
|
*
|
|
* The recycled area is always at the tail of a partially used large
|
|
* page.
|
|
*
|
|
* RETURNS:
|
|
* Address of corresponding remapped pcpu address if match is found;
|
|
* otherwise, NULL.
|
|
*/
|
|
void *pcpu_lpage_remapped(void *kaddr)
|
|
{
|
|
unsigned long unit_mask = pcpul_unit_size - 1;
|
|
void *lpage_addr = (void *)((unsigned long)kaddr & ~unit_mask);
|
|
unsigned long offset = (unsigned long)kaddr & unit_mask;
|
|
int left = 0, right = num_possible_cpus() - 1;
|
|
int pos;
|
|
|
|
/* pcpul in use at all? */
|
|
if (!pcpul_map)
|
|
return NULL;
|
|
|
|
/* okay, perform binary search */
|
|
while (left <= right) {
|
|
pos = (left + right) / 2;
|
|
|
|
if (pcpul_map[pos].ptr < lpage_addr)
|
|
left = pos + 1;
|
|
else if (pcpul_map[pos].ptr > lpage_addr)
|
|
right = pos - 1;
|
|
else {
|
|
/* it shouldn't be in the area for the first chunk */
|
|
WARN_ON(offset < pcpul_size);
|
|
|
|
return pcpul_vm.addr +
|
|
pcpul_map[pos].cpu * pcpul_unit_size + offset;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Generic percpu area setup.
|
|
*
|
|
* The embedding helper is used because its behavior closely resembles
|
|
* the original non-dynamic generic percpu area setup. This is
|
|
* important because many archs have addressing restrictions and might
|
|
* fail if the percpu area is located far away from the previous
|
|
* location. As an added bonus, in non-NUMA cases, embedding is
|
|
* generally a good idea TLB-wise because percpu area can piggy back
|
|
* on the physical linear memory mapping which uses large page
|
|
* mappings on applicable archs.
|
|
*/
|
|
#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
|
|
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
|
|
EXPORT_SYMBOL(__per_cpu_offset);
|
|
|
|
void __init setup_per_cpu_areas(void)
|
|
{
|
|
size_t static_size = __per_cpu_end - __per_cpu_start;
|
|
ssize_t unit_size;
|
|
unsigned long delta;
|
|
unsigned int cpu;
|
|
|
|
/*
|
|
* Always reserve area for module percpu variables. That's
|
|
* what the legacy allocator did.
|
|
*/
|
|
unit_size = pcpu_embed_first_chunk(static_size, PERCPU_MODULE_RESERVE,
|
|
PERCPU_DYNAMIC_RESERVE);
|
|
if (unit_size < 0)
|
|
panic("Failed to initialized percpu areas.");
|
|
|
|
delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
|
|
for_each_possible_cpu(cpu)
|
|
__per_cpu_offset[cpu] = delta + cpu * unit_size;
|
|
}
|
|
#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
|