--- /dev/null
+/*
+ * 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/mm.h>
+
+#include <asm/atomic.h>
+#include <asm/agp.h>
+
+#include "ttm/ttm_bo_driver.h"
+#include "ttm/ttm_page_alloc.h"
+
+
+#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;
+ int gfp_flags;
+ unsigned npages;
+};
+
+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 shrinker mm_shrink;
+ atomic_t page_alloc_inited;
+ 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 ttm_pool_manager _manager = {
+ .page_alloc_inited = ATOMIC_INIT(0)
+};
+
+#ifdef CONFIG_X86
+/* TODO: add this to x86 like _uc, this version here is inefficient */
+static int set_pages_array_wc(struct page **pages, int addrinarray)
+{
+ int i;
+
+ for (i = 0; i < addrinarray; i++)
+ set_memory_wc((unsigned long)page_address(pages[i]), 1);
+ return 0;
+}
+#else
+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] 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;
+}
+
+/**
+ * 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 "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;
+}
+
+/**
+ * Calback for mm to request pool to reduce number of page held.
+ */
+static int ttm_pool_mm_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] 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] 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 has to be reed */
+ 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, int 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] 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] 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->npages += alloc_size;
+ } else {
+ printk(KERN_ERR "[ttm] 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)
+{
+ struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
+ struct page *p = NULL;
+ int gfp_flags = 0;
+ 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_HIGHMEM;
+
+ for (r = 0; r < count; ++r) {
+ p = alloc_page(gfp_flags);
+ if (!p) {
+
+ printk(KERN_ERR "[ttm] 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] Failed to allocate extra pages "
+ "for large request.");
+ ttm_put_pages(pages, 0, flags, cstate);
+ 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)
+{
+ 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)
+{
+ spin_lock_init(&pool->lock);
+ pool->fill_lock = false;
+ INIT_LIST_HEAD(&pool->list);
+ pool->npages = 0;
+ pool->gfp_flags = flags;
+}
+
+int ttm_page_alloc_init(unsigned max_pages)
+{
+ if (atomic_add_return(1, &_manager.page_alloc_inited) > 1)
+ return 0;
+
+ printk(KERN_INFO "[ttm] Initializing pool allocator.\n");
+
+ ttm_page_pool_init_locked(&_manager.wc_pool, GFP_HIGHUSER);
+
+ ttm_page_pool_init_locked(&_manager.uc_pool, GFP_HIGHUSER);
+
+ ttm_page_pool_init_locked(&_manager.wc_pool_dma32, GFP_USER | GFP_DMA32);
+
+ ttm_page_pool_init_locked(&_manager.uc_pool_dma32, GFP_USER | GFP_DMA32);
+
+ _manager.options.max_size = max_pages;
+ _manager.options.small = SMALL_ALLOCATION;
+ _manager.options.alloc_size = NUM_PAGES_TO_ALLOC;
+
+ ttm_pool_mm_shrink_init(&_manager);
+
+ return 0;
+}
+
+void ttm_page_alloc_fini()
+{
+ int i;
+
+ if (atomic_sub_return(1, &_manager.page_alloc_inited) > 0)
+ return;
+
+ printk(KERN_INFO "[ttm] Finilizing 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);
+}
projects / linux-beck.git / commitdiff