2 * Copyright (c) Red Hat Inc.
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sub license,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the
12 * next paragraph) shall be included in all copies or substantial portions
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
23 * Authors: Dave Airlie <airlied@redhat.com>
24 * Jerome Glisse <jglisse@redhat.com>
25 * Pauli Nieminen <suokkos@gmail.com>
28 /* simple list based uncached page pool
29 * - Pool collects resently freed pages for reuse
30 * - Use page->lru to keep a free list
31 * - doesn't track currently in use pages
33 #include <linux/list.h>
34 #include <linux/spinlock.h>
35 #include <linux/highmem.h>
36 #include <linux/mm_types.h>
37 #include <linux/module.h>
39 #include <linux/seq_file.h> /* for seq_printf */
40 #include <linux/slab.h>
42 #include <asm/atomic.h>
45 #include "ttm/ttm_bo_driver.h"
46 #include "ttm/ttm_page_alloc.h"
49 #define NUM_PAGES_TO_ALLOC (PAGE_SIZE/sizeof(struct page *))
50 #define SMALL_ALLOCATION 16
51 #define FREE_ALL_PAGES (~0U)
52 /* times are in msecs */
53 #define PAGE_FREE_INTERVAL 1000
56 * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
58 * @lock: Protects the shared pool from concurrnet access. Must be used with
59 * irqsave/irqrestore variants because pool allocator maybe called from
61 * @fill_lock: Prevent concurrent calls to fill.
62 * @list: Pool of free uc/wc pages for fast reuse.
63 * @gfp_flags: Flags to pass for alloc_page.
64 * @npages: Number of pages in pool.
66 struct ttm_page_pool {
69 struct list_head list;
74 unsigned long nrefills;
78 * Limits for the pool. They are handled without locks because only place where
79 * they may change is in sysfs store. They won't have immediate effect anyway
80 * so forcing serialiazation to access them is pointless.
83 struct ttm_pool_opts {
92 * struct ttm_pool_manager - Holds memory pools for fst allocation
94 * Manager is read only object for pool code so it doesn't need locking.
96 * @free_interval: minimum number of jiffies between freeing pages from pool.
97 * @page_alloc_inited: reference counting for pool allocation.
98 * @work: Work that is used to shrink the pool. Work is only run when there is
100 * @small_allocation: Limit in number of pages what is small allocation.
102 * @pools: All pool objects in use.
104 struct ttm_pool_manager {
106 struct shrinker mm_shrink;
107 atomic_t page_alloc_inited;
108 struct ttm_pool_opts options;
111 struct ttm_page_pool pools[NUM_POOLS];
113 struct ttm_page_pool wc_pool;
114 struct ttm_page_pool uc_pool;
115 struct ttm_page_pool wc_pool_dma32;
116 struct ttm_page_pool uc_pool_dma32;
121 static struct attribute ttm_page_pool_max = {
122 .name = "pool_max_size",
123 .mode = S_IRUGO | S_IWUSR
125 static struct attribute ttm_page_pool_small = {
126 .name = "pool_small_allocation",
127 .mode = S_IRUGO | S_IWUSR
129 static struct attribute ttm_page_pool_alloc_size = {
130 .name = "pool_allocation_size",
131 .mode = S_IRUGO | S_IWUSR
134 static struct attribute *ttm_pool_attrs[] = {
136 &ttm_page_pool_small,
137 &ttm_page_pool_alloc_size,
141 static void ttm_pool_kobj_release(struct kobject *kobj)
143 struct ttm_pool_manager *m =
144 container_of(kobj, struct ttm_pool_manager, kobj);
148 static ssize_t ttm_pool_store(struct kobject *kobj,
149 struct attribute *attr, const char *buffer, size_t size)
151 struct ttm_pool_manager *m =
152 container_of(kobj, struct ttm_pool_manager, kobj);
155 chars = sscanf(buffer, "%u", &val);
159 /* Convert kb to number of pages */
160 val = val / (PAGE_SIZE >> 10);
162 if (attr == &ttm_page_pool_max)
163 m->options.max_size = val;
164 else if (attr == &ttm_page_pool_small)
165 m->options.small = val;
166 else if (attr == &ttm_page_pool_alloc_size) {
167 if (val > NUM_PAGES_TO_ALLOC*8) {
168 printk(KERN_ERR "[ttm] Setting allocation size to %lu "
169 "is not allowed. Recomended size is "
171 NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
172 NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
174 } else if (val > NUM_PAGES_TO_ALLOC) {
175 printk(KERN_WARNING "[ttm] Setting allocation size to "
176 "larger than %lu is not recomended.\n",
177 NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
179 m->options.alloc_size = val;
185 static ssize_t ttm_pool_show(struct kobject *kobj,
186 struct attribute *attr, char *buffer)
188 struct ttm_pool_manager *m =
189 container_of(kobj, struct ttm_pool_manager, kobj);
192 if (attr == &ttm_page_pool_max)
193 val = m->options.max_size;
194 else if (attr == &ttm_page_pool_small)
195 val = m->options.small;
196 else if (attr == &ttm_page_pool_alloc_size)
197 val = m->options.alloc_size;
199 val = val * (PAGE_SIZE >> 10);
201 return snprintf(buffer, PAGE_SIZE, "%u\n", val);
204 static const struct sysfs_ops ttm_pool_sysfs_ops = {
205 .show = &ttm_pool_show,
206 .store = &ttm_pool_store,
209 static struct kobj_type ttm_pool_kobj_type = {
210 .release = &ttm_pool_kobj_release,
211 .sysfs_ops = &ttm_pool_sysfs_ops,
212 .default_attrs = ttm_pool_attrs,
215 static struct ttm_pool_manager _manager = {
216 .page_alloc_inited = ATOMIC_INIT(0)
220 static int set_pages_array_wb(struct page **pages, int addrinarray)
225 for (i = 0; i < addrinarray; i++)
226 unmap_page_from_agp(pages[i]);
231 static int set_pages_array_wc(struct page **pages, int addrinarray)
236 for (i = 0; i < addrinarray; i++)
237 map_page_into_agp(pages[i]);
242 static int set_pages_array_uc(struct page **pages, int addrinarray)
247 for (i = 0; i < addrinarray; i++)
248 map_page_into_agp(pages[i]);
255 * Select the right pool or requested caching state and ttm flags. */
256 static struct ttm_page_pool *ttm_get_pool(int flags,
257 enum ttm_caching_state cstate)
261 if (cstate == tt_cached)
269 if (flags & TTM_PAGE_FLAG_DMA32)
272 return &_manager.pools[pool_index];
275 /* set memory back to wb and free the pages. */
276 static void ttm_pages_put(struct page *pages[], unsigned npages)
279 if (set_pages_array_wb(pages, npages))
280 printk(KERN_ERR "[ttm] Failed to set %d pages to wb!\n",
282 for (i = 0; i < npages; ++i)
283 __free_page(pages[i]);
286 static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
287 unsigned freed_pages)
289 pool->npages -= freed_pages;
290 pool->nfrees += freed_pages;
294 * Free pages from pool.
296 * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
297 * number of pages in one go.
299 * @pool: to free the pages from
300 * @free_all: If set to true will free all pages in pool
302 static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
304 unsigned long irq_flags;
306 struct page **pages_to_free;
307 unsigned freed_pages = 0,
308 npages_to_free = nr_free;
310 if (NUM_PAGES_TO_ALLOC < nr_free)
311 npages_to_free = NUM_PAGES_TO_ALLOC;
313 pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
315 if (!pages_to_free) {
316 printk(KERN_ERR "Failed to allocate memory for pool free operation.\n");
321 spin_lock_irqsave(&pool->lock, irq_flags);
323 list_for_each_entry_reverse(p, &pool->list, lru) {
324 if (freed_pages >= npages_to_free)
327 pages_to_free[freed_pages++] = p;
328 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
329 if (freed_pages >= NUM_PAGES_TO_ALLOC) {
330 /* remove range of pages from the pool */
331 __list_del(p->lru.prev, &pool->list);
333 ttm_pool_update_free_locked(pool, freed_pages);
335 * Because changing page caching is costly
336 * we unlock the pool to prevent stalling.
338 spin_unlock_irqrestore(&pool->lock, irq_flags);
340 ttm_pages_put(pages_to_free, freed_pages);
341 if (likely(nr_free != FREE_ALL_PAGES))
342 nr_free -= freed_pages;
344 if (NUM_PAGES_TO_ALLOC >= nr_free)
345 npages_to_free = nr_free;
347 npages_to_free = NUM_PAGES_TO_ALLOC;
351 /* free all so restart the processing */
355 /* Not allowed to fall tough or break because
356 * following context is inside spinlock while we are
364 /* remove range of pages from the pool */
366 __list_del(&p->lru, &pool->list);
368 ttm_pool_update_free_locked(pool, freed_pages);
369 nr_free -= freed_pages;
372 spin_unlock_irqrestore(&pool->lock, irq_flags);
375 ttm_pages_put(pages_to_free, freed_pages);
377 kfree(pages_to_free);
381 /* Get good estimation how many pages are free in pools */
382 static int ttm_pool_get_num_unused_pages(void)
386 for (i = 0; i < NUM_POOLS; ++i)
387 total += _manager.pools[i].npages;
393 * Calback for mm to request pool to reduce number of page held.
395 static int ttm_pool_mm_shrink(int shrink_pages, gfp_t gfp_mask)
397 static atomic_t start_pool = ATOMIC_INIT(0);
399 unsigned pool_offset = atomic_add_return(1, &start_pool);
400 struct ttm_page_pool *pool;
402 pool_offset = pool_offset % NUM_POOLS;
403 /* select start pool in round robin fashion */
404 for (i = 0; i < NUM_POOLS; ++i) {
405 unsigned nr_free = shrink_pages;
406 if (shrink_pages == 0)
408 pool = &_manager.pools[(i + pool_offset)%NUM_POOLS];
409 shrink_pages = ttm_page_pool_free(pool, nr_free);
411 /* return estimated number of unused pages in pool */
412 return ttm_pool_get_num_unused_pages();
415 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
417 manager->mm_shrink.shrink = &ttm_pool_mm_shrink;
418 manager->mm_shrink.seeks = 1;
419 register_shrinker(&manager->mm_shrink);
422 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
424 unregister_shrinker(&manager->mm_shrink);
427 static int ttm_set_pages_caching(struct page **pages,
428 enum ttm_caching_state cstate, unsigned cpages)
431 /* Set page caching */
434 r = set_pages_array_uc(pages, cpages);
436 printk(KERN_ERR "[ttm] Failed to set %d pages to uc!\n",
440 r = set_pages_array_wc(pages, cpages);
442 printk(KERN_ERR "[ttm] Failed to set %d pages to wc!\n",
452 * Free pages the pages that failed to change the caching state. If there is
453 * any pages that have changed their caching state already put them to the
456 static void ttm_handle_caching_state_failure(struct list_head *pages,
457 int ttm_flags, enum ttm_caching_state cstate,
458 struct page **failed_pages, unsigned cpages)
461 /* Failed pages has to be reed */
462 for (i = 0; i < cpages; ++i) {
463 list_del(&failed_pages[i]->lru);
464 __free_page(failed_pages[i]);
469 * Allocate new pages with correct caching.
471 * This function is reentrant if caller updates count depending on number of
472 * pages returned in pages array.
474 static int ttm_alloc_new_pages(struct list_head *pages, int gfp_flags,
475 int ttm_flags, enum ttm_caching_state cstate, unsigned count)
477 struct page **caching_array;
481 unsigned max_cpages = min(count,
482 (unsigned)(PAGE_SIZE/sizeof(struct page *)));
484 /* allocate array for page caching change */
485 caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
487 if (!caching_array) {
488 printk(KERN_ERR "[ttm] unable to allocate table for new pages.");
492 for (i = 0, cpages = 0; i < count; ++i) {
493 p = alloc_page(gfp_flags);
496 printk(KERN_ERR "[ttm] unable to get page %u\n", i);
498 /* store already allocated pages in the pool after
499 * setting the caching state */
501 r = ttm_set_pages_caching(caching_array, cstate, cpages);
503 ttm_handle_caching_state_failure(pages,
505 caching_array, cpages);
511 #ifdef CONFIG_HIGHMEM
512 /* gfp flags of highmem page should never be dma32 so we
513 * we should be fine in such case
518 caching_array[cpages++] = p;
519 if (cpages == max_cpages) {
521 r = ttm_set_pages_caching(caching_array,
524 ttm_handle_caching_state_failure(pages,
526 caching_array, cpages);
533 list_add(&p->lru, pages);
537 r = ttm_set_pages_caching(caching_array, cstate, cpages);
539 ttm_handle_caching_state_failure(pages,
541 caching_array, cpages);
544 kfree(caching_array);
550 * Fill the given pool if there isn't enough pages and requested number of
553 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
554 int ttm_flags, enum ttm_caching_state cstate, unsigned count,
555 unsigned long *irq_flags)
561 * Only allow one pool fill operation at a time.
562 * If pool doesn't have enough pages for the allocation new pages are
563 * allocated from outside of pool.
568 pool->fill_lock = true;
570 /* If allocation request is small and there is not enough
571 * pages in pool we fill the pool first */
572 if (count < _manager.options.small
573 && count > pool->npages) {
574 struct list_head new_pages;
575 unsigned alloc_size = _manager.options.alloc_size;
578 * Can't change page caching if in irqsave context. We have to
579 * drop the pool->lock.
581 spin_unlock_irqrestore(&pool->lock, *irq_flags);
583 INIT_LIST_HEAD(&new_pages);
584 r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
586 spin_lock_irqsave(&pool->lock, *irq_flags);
589 list_splice(&new_pages, &pool->list);
591 pool->npages += alloc_size;
593 printk(KERN_ERR "[ttm] Failed to fill pool (%p).", pool);
594 /* If we have any pages left put them to the pool. */
595 list_for_each_entry(p, &pool->list, lru) {
598 list_splice(&new_pages, &pool->list);
599 pool->npages += cpages;
603 pool->fill_lock = false;
607 * Cut count nubmer of pages from the pool and put them to return list
609 * @return count of pages still to allocate to fill the request.
611 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
612 struct list_head *pages, int ttm_flags,
613 enum ttm_caching_state cstate, unsigned count)
615 unsigned long irq_flags;
619 spin_lock_irqsave(&pool->lock, irq_flags);
620 ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
622 if (count >= pool->npages) {
623 /* take all pages from the pool */
624 list_splice_init(&pool->list, pages);
625 count -= pool->npages;
629 /* find the last pages to include for requested number of pages. Split
630 * pool to begin and halves to reduce search space. */
631 if (count <= pool->npages/2) {
633 list_for_each(p, &pool->list) {
638 i = pool->npages + 1;
639 list_for_each_prev(p, &pool->list) {
644 /* Cut count number of pages from pool */
645 list_cut_position(pages, &pool->list, p);
646 pool->npages -= count;
649 spin_unlock_irqrestore(&pool->lock, irq_flags);
654 * On success pages list will hold count number of correctly
657 int ttm_get_pages(struct list_head *pages, int flags,
658 enum ttm_caching_state cstate, unsigned count)
660 struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
661 struct page *p = NULL;
665 /* set zero flag for page allocation if required */
666 if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
667 gfp_flags |= __GFP_ZERO;
669 /* No pool for cached pages */
671 if (flags & TTM_PAGE_FLAG_DMA32)
672 gfp_flags |= GFP_DMA32;
674 gfp_flags |= __GFP_HIGHMEM;
676 for (r = 0; r < count; ++r) {
677 p = alloc_page(gfp_flags);
680 printk(KERN_ERR "[ttm] unable to allocate page.");
684 list_add(&p->lru, pages);
690 /* combine zero flag to pool flags */
691 gfp_flags |= pool->gfp_flags;
693 /* First we take pages from the pool */
694 count = ttm_page_pool_get_pages(pool, pages, flags, cstate, count);
696 /* clear the pages coming from the pool if requested */
697 if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
698 list_for_each_entry(p, pages, lru) {
699 clear_page(page_address(p));
703 /* If pool didn't have enough pages allocate new one. */
705 /* ttm_alloc_new_pages doesn't reference pool so we can run
706 * multiple requests in parallel.
708 r = ttm_alloc_new_pages(pages, gfp_flags, flags, cstate, count);
710 /* If there is any pages in the list put them back to
712 printk(KERN_ERR "[ttm] Failed to allocate extra pages "
713 "for large request.");
714 ttm_put_pages(pages, 0, flags, cstate);
723 /* Put all pages in pages list to correct pool to wait for reuse */
724 void ttm_put_pages(struct list_head *pages, unsigned page_count, int flags,
725 enum ttm_caching_state cstate)
727 unsigned long irq_flags;
728 struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
729 struct page *p, *tmp;
732 /* No pool for this memory type so free the pages */
734 list_for_each_entry_safe(p, tmp, pages, lru) {
737 /* Make the pages list empty */
738 INIT_LIST_HEAD(pages);
741 if (page_count == 0) {
742 list_for_each_entry_safe(p, tmp, pages, lru) {
747 spin_lock_irqsave(&pool->lock, irq_flags);
748 list_splice_init(pages, &pool->list);
749 pool->npages += page_count;
750 /* Check that we don't go over the pool limit */
752 if (pool->npages > _manager.options.max_size) {
753 page_count = pool->npages - _manager.options.max_size;
754 /* free at least NUM_PAGES_TO_ALLOC number of pages
755 * to reduce calls to set_memory_wb */
756 if (page_count < NUM_PAGES_TO_ALLOC)
757 page_count = NUM_PAGES_TO_ALLOC;
759 spin_unlock_irqrestore(&pool->lock, irq_flags);
761 ttm_page_pool_free(pool, page_count);
764 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
767 spin_lock_init(&pool->lock);
768 pool->fill_lock = false;
769 INIT_LIST_HEAD(&pool->list);
770 pool->npages = pool->nfrees = 0;
771 pool->gfp_flags = flags;
775 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
778 if (atomic_add_return(1, &_manager.page_alloc_inited) > 1)
781 printk(KERN_INFO "[ttm] Initializing pool allocator.\n");
783 ttm_page_pool_init_locked(&_manager.wc_pool, GFP_HIGHUSER, "wc");
785 ttm_page_pool_init_locked(&_manager.uc_pool, GFP_HIGHUSER, "uc");
787 ttm_page_pool_init_locked(&_manager.wc_pool_dma32, GFP_USER | GFP_DMA32,
790 ttm_page_pool_init_locked(&_manager.uc_pool_dma32, GFP_USER | GFP_DMA32,
793 _manager.options.max_size = max_pages;
794 _manager.options.small = SMALL_ALLOCATION;
795 _manager.options.alloc_size = NUM_PAGES_TO_ALLOC;
797 kobject_init(&_manager.kobj, &ttm_pool_kobj_type);
798 ret = kobject_add(&_manager.kobj, &glob->kobj, "pool");
799 if (unlikely(ret != 0)) {
800 kobject_put(&_manager.kobj);
804 ttm_pool_mm_shrink_init(&_manager);
809 void ttm_page_alloc_fini()
813 if (atomic_sub_return(1, &_manager.page_alloc_inited) > 0)
816 printk(KERN_INFO "[ttm] Finilizing pool allocator.\n");
817 ttm_pool_mm_shrink_fini(&_manager);
819 for (i = 0; i < NUM_POOLS; ++i)
820 ttm_page_pool_free(&_manager.pools[i], FREE_ALL_PAGES);
822 kobject_put(&_manager.kobj);
825 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
827 struct ttm_page_pool *p;
829 char *h[] = {"pool", "refills", "pages freed", "size"};
830 if (atomic_read(&_manager.page_alloc_inited) == 0) {
831 seq_printf(m, "No pool allocator running.\n");
834 seq_printf(m, "%6s %12s %13s %8s\n",
835 h[0], h[1], h[2], h[3]);
836 for (i = 0; i < NUM_POOLS; ++i) {
837 p = &_manager.pools[i];
839 seq_printf(m, "%6s %12ld %13ld %8d\n",
840 p->name, p->nrefills,
841 p->nfrees, p->npages);
845 EXPORT_SYMBOL(ttm_page_alloc_debugfs);