/*
* Copyright (c) Red Hat Inc.
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sub license,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors: Dave Airlie <airlied@redhat.com>
* Jerome Glisse <jglisse@redhat.com>
* Pauli Nieminen <suokkos@gmail.com>
*/
/* simple list based uncached page pool
* - Pool collects resently freed pages for reuse
* - Use page->lru to keep a free list
* - doesn't track currently in use pages
*/
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/highmem.h>
#include <linux/mm_types.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/seq_file.h> /* for seq_printf */
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <asm/atomic.h>
#include "ttm/ttm_bo_driver.h"
#include "ttm/ttm_page_alloc.h"
#ifdef TTM_HAS_AGP
#include <asm/agp.h>
#endif
#define NUM_PAGES_TO_ALLOC (PAGE_SIZE/sizeof(struct page *))
#define SMALL_ALLOCATION 16
#define FREE_ALL_PAGES (~0U)
/* times are in msecs */
#define PAGE_FREE_INTERVAL 1000
/**
* struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
*
* @lock: Protects the shared pool from concurrnet access. Must be used with
* irqsave/irqrestore variants because pool allocator maybe called from
* delayed work.
* @fill_lock: Prevent concurrent calls to fill.
* @list: Pool of free uc/wc pages for fast reuse.
* @gfp_flags: Flags to pass for alloc_page.
* @npages: Number of pages in pool.
*/
struct ttm_page_pool {
spinlock_t lock;
bool fill_lock;
struct list_head list;
gfp_t gfp_flags;
unsigned npages;
char *name;
unsigned long nfrees;
unsigned long nrefills;
};
/**
* Limits for the pool. They are handled without locks because only place where
* they may change is in sysfs store. They won't have immediate effect anyway
* so forcing serialization to access them is pointless.
*/
struct ttm_pool_opts {
unsigned alloc_size;
unsigned max_size;
unsigned small;
};
#define NUM_POOLS 4
/**
* struct ttm_pool_manager - Holds memory pools for fst allocation
*
* Manager is read only object for pool code so it doesn't need locking.
*
* @free_interval: minimum number of jiffies between freeing pages from pool.
* @page_alloc_inited: reference counting for pool allocation.
* @work: Work that is used to shrink the pool. Work is only run when there is
* some pages to free.
* @small_allocation: Limit in number of pages what is small allocation.
*
* @pools: All pool objects in use.
**/
struct ttm_pool_manager {
struct kobject kobj;
struct shrinker mm_shrink;
struct ttm_pool_opts options;
union {
struct ttm_page_pool pools[NUM_POOLS];
struct {
struct ttm_page_pool wc_pool;
struct ttm_page_pool uc_pool;
struct ttm_page_pool wc_pool_dma32;
struct ttm_page_pool uc_pool_dma32;
} ;
};
};
static struct attribute ttm_page_pool_max = {
.name = "pool_max_size",
.mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_page_pool_small = {
.name = "pool_small_allocation",
.mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_page_pool_alloc_size = {
.name = "pool_allocation_size",
.mode = S_IRUGO | S_IWUSR
};
static struct attribute *ttm_pool_attrs[] = {
&ttm_page_pool_max,
&ttm_page_pool_small,
&ttm_page_pool_alloc_size,
NULL
};
static void ttm_pool_kobj_release(struct kobject *kobj)
{
struct ttm_pool_manager *m =
container_of(kobj, struct ttm_pool_manager, kobj);
kfree(m);
}
static ssize_t ttm_pool_store(struct kobject *kobj,
struct attribute *attr, const char *buffer, size_t size)
{
struct ttm_pool_manager *m =
container_of(kobj, struct ttm_pool_manager, kobj);
int chars;
unsigned val;
chars = sscanf(buffer, "%u", &val);
if (chars == 0)
return size;
/* Convert kb to number of pages */
val = val / (PAGE_SIZE >> 10);
if (attr == &ttm_page_pool_max)
m->options.max_size = val;
else if (attr == &ttm_page_pool_small)
m->options.small = val;
else if (attr == &ttm_page_pool_alloc_size) {
if (val > NUM_PAGES_TO_ALLOC*8) {
printk(KERN_ERR TTM_PFX
"Setting allocation size to %lu "
"is not allowed. Recommended size is "
"%lu\n",
NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
return size;
} else if (val > NUM_PAGES_TO_ALLOC) {
printk(KERN_WARNING TTM_PFX
"Setting allocation size to "
"larger than %lu is not recommended.\n",
NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
}
m->options.alloc_size = val;
}
return size;
}
static ssize_t ttm_pool_show(struct kobject *kobj,
struct attribute *attr, char *buffer)
{
struct ttm_pool_manager *m =
container_of(kobj, struct ttm_pool_manager, kobj);
unsigned val = 0;
if (attr == &ttm_page_pool_max)
val = m->options.max_size;
else if (attr == &ttm_page_pool_small)
val = m->options.small;
else if (attr == &ttm_page_pool_alloc_size)
val = m->options.alloc_size;
val = val * (PAGE_SIZE >> 10);
return snprintf(buffer, PAGE_SIZE, "%u\n", val);
}
static const struct sysfs_ops ttm_pool_sysfs_ops = {
.show = &ttm_pool_show,
.store = &ttm_pool_store,
};
static struct kobj_type ttm_pool_kobj_type = {
.release = &ttm_pool_kobj_release,
.sysfs_ops = &ttm_pool_sysfs_ops,
.default_attrs = ttm_pool_attrs,
};
static struct ttm_pool_manager *_manager;
#ifndef CONFIG_X86
static int set_pages_array_wb(struct page **pages, int addrinarray)
{
#ifdef TTM_HAS_AGP
int i;
for (i = 0; i < addrinarray; i++)
unmap_page_from_agp(pages[i]);
#endif
return 0;
}
static int set_pages_array_wc(struct page **pages, int addrinarray)
{
#ifdef TTM_HAS_AGP
int i;
for (i = 0; i < addrinarray; i++)
map_page_into_agp(pages[i]);
#endif
return 0;
}
static int set_pages_array_uc(struct page **pages, int addrinarray)
{
#ifdef TTM_HAS_AGP
int i;
for (i = 0; i < addrinarray; i++)
map_page_into_agp(pages[i]);
#endif
return 0;
}
#endif
/**
* Select the right pool or requested caching state and ttm flags. */
static struct ttm_page_pool *ttm_get_pool(int flags,
enum ttm_caching_state cstate)
{
int pool_index;
if (cstate == tt_cached)
return NULL;
if (cstate == tt_wc)
pool_index = 0x0;
else
pool_index = 0x1;
if (flags & TTM_PAGE_FLAG_DMA32)
pool_index |= 0x2;
return &_manager->pools[pool_index];
}
/* set memory back to wb and free the pages. */
static void ttm_pages_put(struct page *pages[], unsigned npages)
{
unsigned i;
if (set_pages_array_wb(pages, npages))
printk(KERN_ERR TTM_PFX "Failed to set %d pages to wb!\n",
npages);
for (i = 0; i < npages; ++i)
__free_page(pages[i]);
}
static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
unsigned freed_pages)
{
pool->npages -= freed_pages;
pool->nfrees += freed_pages;
}
/**
* Free pages from pool.
*
* To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
* number of pages in one go.
*
* @pool: to free the pages from
* @free_all: If set to true will free all pages in pool
**/
static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
{
unsigned long irq_flags;
struct page *p;
struct page **pages_to_free;
unsigned freed_pages = 0,
npages_to_free = nr_free;
if (NUM_PAGES_TO_ALLOC < nr_free)
npages_to_free = NUM_PAGES_TO_ALLOC;
pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
GFP_KERNEL);
if (!pages_to_free) {
printk(KERN_ERR TTM_PFX
"Failed to allocate memory for pool free operation.\n");
return 0;
}
restart:
spin_lock_irqsave(&pool->lock, irq_flags);
list_for_each_entry_reverse(p, &pool->list, lru) {
if (freed_pages >= npages_to_free)
break;
pages_to_free[freed_pages++] = p;
/* We can only remove NUM_PAGES_TO_ALLOC at a time. */
if (freed_pages >= NUM_PAGES_TO_ALLOC) {
/* remove range of pages from the pool */
__list_del(p->lru.prev, &pool->list);
ttm_pool_update_free_locked(pool, freed_pages);
/**
* Because changing page caching is costly
* we unlock the pool to prevent stalling.
*/
spin_unlock_irqrestore(&pool->lock, irq_flags);
ttm_pages_put(pages_to_free, freed_pages);
if (likely(nr_free != FREE_ALL_PAGES))
nr_free -= freed_pages;
if (NUM_PAGES_TO_ALLOC >= nr_free)
npages_to_free = nr_free;
else
npages_to_free = NUM_PAGES_TO_ALLOC;
freed_pages = 0;
/* free all so restart the processing */
if (nr_free)
goto restart;
/* Not allowed to fall tough or break because
* following context is inside spinlock while we are
* outside here.
*/
goto out;
}
}
/* remove range of pages from the pool */
if (freed_pages) {
__list_del(&p->lru, &pool->list);
ttm_pool_update_free_locked(pool, freed_pages);
nr_free -= freed_pages;
}
spin_unlock_irqrestore(&pool->lock, irq_flags);
if (freed_pages)
ttm_pages_put(pages_to_free, freed_pages);
out:
kfree(pages_to_free);
return nr_free;
}
/* Get good estimation how many pages are free in pools */
static int ttm_pool_get_num_unused_pages(void)
{
unsigned i;
int total = 0;
for (i = 0; i < NUM_POOLS; ++i)
total += _manager->pools[i].npages;
return total;
}
/**
* Callback for mm to request pool to reduce number of page held.
*/
static int ttm_pool_mm_shrink(struct shrinker *shrink, int shrink_pages, gfp_t gfp_mask)
{
static atomic_t start_pool = ATOMIC_INIT(0);
unsigned i;
unsigned pool_offset = atomic_add_return(1, &start_pool);
struct ttm_page_pool *pool;
pool_offset = pool_offset % NUM_POOLS;
/* select start pool in round robin fashion */
for (i = 0; i < NUM_POOLS; ++i) {
unsigned nr_free = shrink_pages;
if (shrink_pages == 0)
break;
pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
shrink_pages = ttm_page_pool_free(pool, nr_free);
}
/* return estimated number of unused pages in pool */
return ttm_pool_get_num_unused_pages();
}
static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
{
manager->mm_shrink.shrink = &ttm_pool_mm_shrink;
manager->mm_shrink.seeks = 1;
register_shrinker(&manager->mm_shrink);
}
static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
{
unregister_shrinker(&manager->mm_shrink);
}
static int ttm_set_pages_caching(struct page **pages,
enum ttm_caching_state cstate, unsigned cpages)
{
int r = 0;
/* Set page caching */
switch (cstate) {
case tt_uncached:
r = set_pages_array_uc(pages, cpages);
if (r)
printk(KERN_ERR TTM_PFX
"Failed to set %d pages to uc!\n",
cpages);
break;
case tt_wc:
r = set_pages_array_wc(pages, cpages);
if (r)
printk(KERN_ERR TTM_PFX
"Failed to set %d pages to wc!\n",
cpages);
break;
default:
break;
}
return r;
}
/**
* Free pages the pages that failed to change the caching state. If there is
* any pages that have changed their caching state already put them to the
* pool.
*/
static void ttm_handle_caching_state_failure(struct list_head *pages,
int ttm_flags, enum ttm_caching_state cstate,
struct page **failed_pages, unsigned cpages)
{
unsigned i;
/* Failed pages have to be freed */
for (i = 0; i < cpages; ++i) {
list_del(&failed_pages[i]->lru);
__free_page(failed_pages[i]);
}
}
/**
* Allocate new pages with correct caching.
*
* This function is reentrant if caller updates count depending on number of
* pages returned in pages array.
*/
static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
int ttm_flags, enum ttm_caching_state cstate, unsigned count)
{
struct page **caching_array;
struct page *p;
int r = 0;
unsigned i, cpages;
unsigned max_cpages = min(count,
(unsigned)(PAGE_SIZE/sizeof(struct page *)));
/* allocate array for page caching change */
caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
if (!caching_array) {
printk(KERN_ERR TTM_PFX
"Unable to allocate table for new pages.");
return -ENOMEM;
}
for (i = 0, cpages = 0; i < count; ++i) {
p = alloc_page(gfp_flags);
if (!p) {
printk(KERN_ERR TTM_PFX "Unable to get page %u.\n", i);
/* store already allocated pages in the pool after
* setting the caching state */
if (cpages) {
r = ttm_set_pages_caching(caching_array,
cstate, cpages);
if (r)
ttm_handle_caching_state_failure(pages,
ttm_flags, cstate,
caching_array, cpages);
}
r = -ENOMEM;
goto out;
}
#ifdef CONFIG_HIGHMEM
/* gfp flags of highmem page should never be dma32 so we
* we should be fine in such case
*/
if (!PageHighMem(p))
#endif
{
caching_array[cpages++] = p;
if (cpages == max_cpages) {
r = ttm_set_pages_caching(caching_array,
cstate, cpages);
if (r) {
ttm_handle_caching_state_failure(pages,
ttm_flags, cstate,
caching_array, cpages);
goto out;
}
cpages = 0;
}
}
list_add(&p->lru, pages);
}
if (cpages) {
r = ttm_set_pages_caching(caching_array, cstate, cpages);
if (r)
ttm_handle_caching_state_failure(pages,
ttm_flags, cstate,
caching_array, cpages);
}
out:
kfree(caching_array);
return r;
}
/**
* Fill the given pool if there isn't enough pages and requested number of
* pages is small.
*/
static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
int ttm_flags, enum ttm_caching_state cstate, unsigned count,
unsigned long *irq_flags)
{
struct page *p;
int r;
unsigned cpages = 0;
/**
* Only allow one pool fill operation at a time.
* If pool doesn't have enough pages for the allocation new pages are
* allocated from outside of pool.
*/
if (pool->fill_lock)
return;
pool->fill_lock = true;
/* If allocation request is small and there is not enough
* pages in pool we fill the pool first */
if (count < _manager->options.small
&& count > pool->npages) {
struct list_head new_pages;
unsigned alloc_size = _manager->options.alloc_size;
/**
* Can't change page caching if in irqsave context. We have to
* drop the pool->lock.
*/
spin_unlock_irqrestore(&pool->lock, *irq_flags);
INIT_LIST_HEAD(&new_pages);
r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
cstate, alloc_size);
spin_lock_irqsave(&pool->lock, *irq_flags);
if (!r) {
list_splice(&new_pages, &pool->list);
++pool->nrefills;
pool->npages += alloc_size;
} else {
printk(KERN_ERR TTM_PFX
"Failed to fill pool (%p).", pool);
/* If we have any pages left put them to the pool. */
list_for_each_entry(p, &pool->list, lru) {
++cpages;
}
list_splice(&new_pages, &pool->list);
pool->npages += cpages;
}
}
pool->fill_lock = false;
}
/**
* Cut count nubmer of pages from the pool and put them to return list
*
* @return count of pages still to allocate to fill the request.
*/
static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
struct list_head *pages, int ttm_flags,
enum ttm_caching_state cstate, unsigned count)
{
unsigned long irq_flags;
struct list_head *p;
unsigned i;
spin_lock_irqsave(&pool->lock, irq_flags);
ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
if (count >= pool->npages) {
/* take all pages from the pool */
list_splice_init(&pool->list, pages);
count -= pool->npages;
pool->npages = 0;
goto out;
}
/* find the last pages to include for requested number of pages. Split
* pool to begin and halves to reduce search space. */
if (count <= pool->npages/2) {
i = 0;
list_for_each(p, &pool->list) {
if (++i == count)
break;
}
} else {
i = pool->npages + 1;
list_for_each_prev(p, &pool->list) {
if (--i == count)
break;
}
}
/* Cut count number of pages from pool */
list_cut_position(pages, &pool->list, p);
pool->npages -= count;
count = 0;
out:
spin_unlock_irqrestore(&pool->lock, irq_flags);
return count;
}
/*
* On success pages list will hold count number of correctly
* cached pages.
*/
int ttm_get_pages(struct list_head *pages, int flags,
enum ttm_caching_state cstate, unsigned count,
dma_addr_t *dma_address)
{
struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
struct page *p = NULL;
gfp_t gfp_flags = GFP_USER;
int r;
/* set zero flag for page allocation if required */
if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
gfp_flags |= __GFP_ZERO;
/* No pool for cached pages */
if (pool == NULL) {
if (flags & TTM_PAGE_FLAG_DMA32)
gfp_flags |= GFP_DMA32;
else
gfp_flags |= GFP_HIGHUSER;
for (r = 0; r < count; ++r) {
p = alloc_page(gfp_flags);
if (!p) {
printk(KERN_ERR TTM_PFX
"Unable to allocate page.");
return -ENOMEM;
}
list_add(&p->lru, pages);
}
return 0;
}
/* combine zero flag to pool flags */
gfp_flags |= pool->gfp_flags;
/* First we take pages from the pool */
count = ttm_page_pool_get_pages(pool, pages, flags, cstate, count);
/* clear the pages coming from the pool if requested */
if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
list_for_each_entry(p, pages, lru) {
clear_page(page_address(p));
}
}
/* If pool didn't have enough pages allocate new one. */
if (count > 0) {
/* ttm_alloc_new_pages doesn't reference pool so we can run
* multiple requests in parallel.
**/
r = ttm_alloc_new_pages(pages, gfp_flags, flags, cstate, count);
if (r) {
/* If there is any pages in the list put them back to
* the pool. */
printk(KERN_ERR TTM_PFX
"Failed to allocate extra pages "
"for large request.");
ttm_put_pages(pages, 0, flags, cstate, NULL);
return r;
}
}
return 0;
}
/* Put all pages in pages list to correct pool to wait for reuse */
void ttm_put_pages(struct list_head *pages, unsigned page_count, int flags,
enum ttm_caching_state cstate, dma_addr_t *dma_address)
{
unsigned long irq_flags;
struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
struct page *p, *tmp;
if (pool == NULL) {
/* No pool for this memory type so free the pages */
list_for_each_entry_safe(p, tmp, pages, lru) {
__free_page(p);
}
/* Make the pages list empty */
INIT_LIST_HEAD(pages);
return;
}
if (page_count == 0) {
list_for_each_entry_safe(p, tmp, pages, lru) {
++page_count;
}
}
spin_lock_irqsave(&pool->lock, irq_flags);
list_splice_init(pages, &pool->list);
pool->npages += page_count;
/* Check that we don't go over the pool limit */
page_count = 0;
if (pool->npages > _manager->options.max_size) {
page_count = pool->npages - _manager->options.max_size;
/* free at least NUM_PAGES_TO_ALLOC number of pages
* to reduce calls to set_memory_wb */
if (page_count < NUM_PAGES_TO_ALLOC)
page_count = NUM_PAGES_TO_ALLOC;
}
spin_unlock_irqrestore(&pool->lock, irq_flags);
if (page_count)
ttm_page_pool_free(pool, page_count);
}
static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
char *name)
{
spin_lock_init(&pool->lock);
pool->fill_lock = false;
INIT_LIST_HEAD(&pool->list);
pool->npages = pool->nfrees = 0;
pool->gfp_flags = flags;
pool->name = name;
}
int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
{
int ret;
WARN_ON(_manager);
printk(KERN_INFO TTM_PFX "Initializing pool allocator.\n");
_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");
ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
GFP_USER | GFP_DMA32, "wc dma");
ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
GFP_USER | GFP_DMA32, "uc dma");
_manager->options.max_size = max_pages;
_manager->options.small = SMALL_ALLOCATION;
_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
&glob->kobj, "pool");
if (unlikely(ret != 0)) {
kobject_put(&_manager->kobj);
_manager = NULL;
return ret;
}
ttm_pool_mm_shrink_init(_manager);
return 0;
}
void ttm_page_alloc_fini(void)
{
int i;
printk(KERN_INFO TTM_PFX "Finalizing pool allocator.\n");
ttm_pool_mm_shrink_fini(_manager);
for (i = 0; i < NUM_POOLS; ++i)
ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
kobject_put(&_manager->kobj);
_manager = NULL;
}
int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
{
struct ttm_page_pool *p;
unsigned i;
char *h[] = {"pool", "refills", "pages freed", "size"};
if (!_manager) {
seq_printf(m, "No pool allocator running.\n");
return 0;
}
seq_printf(m, "%6s %12s %13s %8s\n",
h[0], h[1], h[2], h[3]);
for (i = 0; i < NUM_POOLS; ++i) {
p = &_manager->pools[i];
seq_printf(m, "%6s %12ld %13ld %8d\n",
p->name, p->nrefills,
p->nfrees, p->npages);
}
return 0;
}
EXPORT_SYMBOL(ttm_page_alloc_debugfs);
