Re: [PATCH 08/11] ttm: Provide DMA aware TTM page pool code.
From: Jerome Glisse
Date: Mon Oct 31 2011 - 15:33:15 EST
On Wed, Oct 19, 2011 at 06:19:29PM -0400, Konrad Rzeszutek Wilk wrote:
> In TTM world the pages for the graphic drivers are kept in three different
> pools: write combined, uncached, and cached (write-back). When the pages
> are used by the graphic driver the graphic adapter via its built in MMU
> (or AGP) programs these pages in. The programming requires the virtual address
> (from the graphic adapter perspective) and the physical address (either System RAM
> or the memory on the card) which is obtained using the pci_map_* calls (which does the
> virtual to physical - or bus address translation). During the graphic application's
> "life" those pages can be shuffled around, swapped out to disk, moved from the
> VRAM to System RAM or vice-versa. This all works with the existing TTM pool code
> - except when we want to use the software IOTLB (SWIOTLB) code to "map" the physical
> addresses to the graphic adapter MMU. We end up programming the bounce buffer's
> physical address instead of the TTM pool memory's and get a non-worky driver.
> There are two solutions:
> 1) using the DMA API to allocate pages that are screened by the DMA API, or
> 2) using the pci_sync_* calls to copy the pages from the bounce-buffer and back.
>
> This patch fixes the issue by allocating pages using the DMA API. The second
> is a viable option - but it has performance drawbacks and potential correctness
> issues - think of the write cache page being bounced (SWIOTLB->TTM), the
> WC is set on the TTM page and the copy from SWIOTLB not making it to the TTM
> page until the page has been recycled in the pool (and used by another application).
>
> The bounce buffer does not get activated often - only in cases where we have
> a 32-bit capable card and we want to use a page that is allocated above the
> 4GB limit. The bounce buffer offers the solution of copying the contents
> of that 4GB page to an location below 4GB and then back when the operation has been
> completed (or vice-versa). This is done by using the 'pci_sync_*' calls.
> Note: If you look carefully enough in the existing TTM page pool code you will
> notice the GFP_DMA32 flag is used - which should guarantee that the provided page
> is under 4GB. It certainly is the case, except this gets ignored in two cases:
> - If user specifies 'swiotlb=force' which bounces _every_ page.
> - If user is using a Xen's PV Linux guest (which uses the SWIOTLB and the
> underlaying PFN's aren't necessarily under 4GB).
>
> To not have this extra copying done the other option is to allocate the pages
> using the DMA API so that there is not need to map the page and perform the
> expensive 'pci_sync_*' calls.
>
> This DMA API capable TTM pool requires for this the 'struct device' to
> properly call the DMA API. It also has to track the virtual and bus address of
> the page being handed out in case it ends up being swapped out or de-allocated -
> to make sure it is de-allocated using the proper's 'struct device'.
>
> Implementation wise the code keeps two lists: one that is attached to the
> 'struct device' (via the dev->dma_pools list) and a global one to be used when
> the 'struct device' is unavailable (think shrinker code). The global list can
> iterate over all of the 'struct device' and its associated dma_pool. The list
> in dev->dma_pools can only iterate the device's dma_pool.
> /[struct device_pool]\
> /---------------------------------------------------| dev |
> / +-------| dma_pool |
> /-----+------\ / \--------------------/
> |struct device| /-->[struct dma_pool for WC]</ /[struct device_pool]\
> | dma_pools +----+ /-| dev |
> | ... | \--->[struct dma_pool for uncached]<-/--| dma_pool |
> \-----+------/ / \--------------------/
> \----------------------------------------------/
> [Two pools associated with the device (WC and UC), and the parallel list
> containing the 'struct dev' and 'struct dma_pool' entries]
>
> The maximum amount of dma pools a device can have is six: write-combined,
> uncached, and cached; then there are the DMA32 variants which are:
> write-combined dma32, uncached dma32, and cached dma32.
>
> Currently this code only gets activated when any variant of the SWIOTLB IOMMU
> code is running (Intel without VT-d, AMD without GART, IBM Calgary and Xen PV
> with PCI devices).
>
> Tested-by: Michel Dänzer <michel@xxxxxxxxxxx>
> [v1: Using swiotlb_nr_tbl instead of swiotlb_enabled]
> [v2: Major overhaul - added 'inuse_list' to seperate used from inuse and reorder
> the order of lists to get better performance.]
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
> drivers/gpu/drm/ttm/Makefile | 3 +
> drivers/gpu/drm/ttm/ttm_memory.c | 2 +
> drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 1394 ++++++++++++++++++++++++++++++
> include/drm/ttm/ttm_page_alloc.h | 31 +
> 4 files changed, 1430 insertions(+), 0 deletions(-)
> create mode 100644 drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
>
> diff --git a/drivers/gpu/drm/ttm/Makefile b/drivers/gpu/drm/ttm/Makefile
> index f3cf6f0..8300bc0 100644
> --- a/drivers/gpu/drm/ttm/Makefile
> +++ b/drivers/gpu/drm/ttm/Makefile
> @@ -7,4 +7,7 @@ ttm-y := ttm_agp_backend.o ttm_memory.o ttm_tt.o ttm_bo.o \
> ttm_object.o ttm_lock.o ttm_execbuf_util.o ttm_page_alloc.o \
> ttm_bo_manager.o
>
> +ifeq ($(CONFIG_SWIOTLB),y)
> +ttm-y += ttm_page_alloc_dma.o
> +endif
> obj-$(CONFIG_DRM_TTM) += ttm.o
> diff --git a/drivers/gpu/drm/ttm/ttm_memory.c b/drivers/gpu/drm/ttm/ttm_memory.c
> index e70ddd8..6d24fe2 100644
> --- a/drivers/gpu/drm/ttm/ttm_memory.c
> +++ b/drivers/gpu/drm/ttm/ttm_memory.c
> @@ -395,6 +395,7 @@ int ttm_mem_global_init(struct ttm_mem_global *glob)
> zone->name, (unsigned long long) zone->max_mem >> 10);
> }
> ttm_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
> + ttm_dma_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
> return 0;
> out_no_zone:
> ttm_mem_global_release(glob);
> @@ -410,6 +411,7 @@ void ttm_mem_global_release(struct ttm_mem_global *glob)
> /* let the page allocator first stop the shrink work. */
> ttm_page_alloc_fini();
>
> + ttm_dma_page_alloc_fini();
> flush_workqueue(glob->swap_queue);
> destroy_workqueue(glob->swap_queue);
> glob->swap_queue = NULL;
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> new file mode 100644
> index 0000000..d6d8240
> --- /dev/null
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> @@ -0,0 +1,1394 @@
> +/*
> + * Copyright 2011 (c) Oracle Corp.
> +
> + * 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.
> + *
> + * Author: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> + */
> +
> +/*
> + * A simple DMA pool losely based on dmapool.c. It has certain advantages
> + * over the DMA pools:
> + * - Pool collects resently freed pages for reuse (and hooks up to
> + * the shrinker).
> + * - Tracks currently in use pages
> + * - Tracks whether the page is UC, WB or cached (and reverts to WB
> + * when freed).
> + */
> +
> +#include <linux/dma-mapping.h>
> +#include <linux/list.h>
> +#include <linux/seq_file.h> /* for seq_printf */
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/highmem.h>
> +#include <linux/mm_types.h>
> +#include <linux/module.h>
> +#include <linux/mm.h>
> +#include <linux/atomic.h>
> +#include <linux/device.h>
> +#include <linux/kthread.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 IS_UNDEFINED (0)
> +#define IS_WC (1<<1)
> +#define IS_UC (1<<2)
> +#define IS_CACHED (1<<3)
> +#define IS_DMA32 (1<<4)
> +
> +enum pool_type {
> + POOL_IS_UNDEFINED,
> + POOL_IS_WC = IS_WC,
> + POOL_IS_UC = IS_UC,
> + POOL_IS_CACHED = IS_CACHED,
> + POOL_IS_WC_DMA32 = IS_WC | IS_DMA32,
> + POOL_IS_UC_DMA32 = IS_UC | IS_DMA32,
> + POOL_IS_CACHED_DMA32 = IS_CACHED | IS_DMA32,
> +};
> +/*
> + * The pool structure. There are usually six pools:
> + * - generic (not restricted to DMA32):
> + * - write combined, uncached, cached.
> + * - dma32 (up to 2^32 - so up 4GB):
> + * - write combined, uncached, cached.
> + * for each 'struct device'. The 'cached' is for pages that are actively used.
> + * The other ones can be shrunk by the shrinker API if neccessary.
> + * @pools: The 'struct device->dma_pools' link.
> + * @type: Type of the pool
> + * @lock: Protects the inuse_list and free_list from concurrnet access. Must be
> + * used with irqsave/irqrestore variants because pool allocator maybe called
> + * from delayed work.
> + * @inuse_list: Pool of pages that are in use. The order is very important and
> + * it is in the order that the TTM pages that are put back are in.
> + * @free_list: Pool of pages that are free to be used. No order requirements.
> + * @dev: The device that is associated with these pools.
> + * @size: Size used during DMA allocation.
> + * @npages_free: Count of available pages for re-use.
> + * @npages_in_use: Count of pages that are in use (each of them
> + * is marked in_use.
> + * @nfrees: Stats when pool is shrinking.
> + * @nrefills: Stats when the pool is grown.
> + * @gfp_flags: Flags to pass for alloc_page.
> + * @fill_lock: Allows only one pool fill operation at time.
> + * @name: Name of the pool.
> + * @dev_name: Name derieved from dev - similar to how dev_info works.
> + * Used during shutdown as the dev_info during release is unavailable.
> + */
> +struct dma_pool {
> + struct list_head pools; /* The 'struct device->dma_pools link */
> + enum pool_type type;
> + spinlock_t lock;
> + struct list_head inuse_list;
> + struct list_head free_list;
> + struct device *dev;
> + unsigned size;
> + unsigned npages_free;
> + unsigned npages_in_use;
> + unsigned long nfrees; /* Stats when shrunk. */
> + unsigned long nrefills; /* Stats when grown. */
> + gfp_t gfp_flags;
> + bool fill_lock;
> + char name[13]; /* "cached dma32" */
> + char dev_name[64]; /* Constructed from dev */
> +};
> +
> +/*
> + * The accounting page keeping track of the allocated page along with
> + * the DMA address.
> + * @page_list: The link to the 'page_list' in 'struct dma_pool'.
> + * @vaddr: The virtual address of the page
> + * @dma: The bus address of the page. If the page is not allocated
> + * via the DMA API, it will be -1.
> + * @in_use: Set to true if in use. Should not be freed.
> + */
> +struct dma_page {
> + struct list_head page_list;
> + void *vaddr;
> + struct page *p;
> + dma_addr_t dma;
> +};
> +
> +/*
> + * 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;
> +};
> +
> +/*
> + * Contains the list of all of the 'struct device' and their corresponding
> + * DMA pools. Guarded by _mutex->lock.
> + * @pools: The link to 'struct ttm_pool_manager->pools'
> + * @dev: The 'struct device' associated with the 'pool'
> + * @pool: The 'struct dma_pool' associated with the 'dev'
> + */
> +struct device_pools {
> + struct list_head pools;
> + struct device *dev;
> + struct dma_pool *pool;
> +};
> +
> +/*
> + * struct ttm_pool_manager - Holds memory pools for fast allocation
> + *
> + * @lock: Lock used when adding/removing from pools
> + * @pools: List of 'struct device' and 'struct dma_pool' tuples.
> + * @options: Limits for the pool.
> + * @npools: Total amount of pools in existence.
> + * @shrinker: The structure used by [un|]register_shrinker
> + */
> +struct ttm_pool_manager {
> + struct mutex lock;
> + struct list_head pools;
> + struct ttm_pool_opts options;
> + unsigned npools;
> + struct shrinker mm_shrink;
> + struct kobject kobj;
> +};
> +
> +static struct ttm_pool_manager *_manager;
> +
> +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,
> +};
> +
> +#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 /* for !CONFIG_X86 */
> +
> +static int ttm_set_pages_caching(struct dma_pool *pool,
> + struct page **pages, unsigned cpages)
> +{
> + int r = 0;
> + /* Set page caching */
> + if (pool->type & IS_UC) {
> + r = set_pages_array_uc(pages, cpages);
> + if (r)
> + pr_err(TTM_PFX
> + "%s: Failed to set %d pages to uc!\n",
> + pool->dev_name, cpages);
> + }
> + if (pool->type & IS_WC) {
> + r = set_pages_array_wc(pages, cpages);
> + if (r)
> + pr_err(TTM_PFX
> + "%s: Failed to set %d pages to wc!\n",
> + pool->dev_name, cpages);
> + }
> + return r;
> +}
> +
> +static void __ttm_dma_free_page(struct dma_pool *pool, struct dma_page *d_page)
> +{
> + dma_addr_t dma = d_page->dma;
> + dma_free_coherent(pool->dev, pool->size, d_page->vaddr, dma);
> +
> + kfree(d_page);
> + d_page = NULL;
> +}
> +static struct dma_page *__ttm_dma_alloc_page(struct dma_pool *pool)
> +{
> + struct dma_page *d_page;
> +
> + d_page = kmalloc(sizeof(struct dma_page), GFP_KERNEL);
> + if (!d_page)
> + return NULL;
> +
> + d_page->vaddr = dma_alloc_coherent(pool->dev, pool->size,
> + &d_page->dma,
> + pool->gfp_flags);
> + d_page->p = virt_to_page(d_page->vaddr);
> + if (!d_page->vaddr) {
> + kfree(d_page);
> + d_page = NULL;
> + }
Move d_page->p = virt_to_page(d_page->vaddr); after if (!d_page->vaddr)
block.
> + return d_page;
> +}
> +static enum pool_type ttm_to_type(int flags, enum ttm_caching_state cstate)
> +{
> + enum pool_type type = IS_UNDEFINED;
> +
> + if (flags & TTM_PAGE_FLAG_DMA32)
> + type |= IS_DMA32;
> + if (cstate == tt_cached)
> + type |= IS_CACHED;
> + else if (cstate == tt_uncached)
> + type |= IS_UC;
> + else
> + type |= IS_WC;
> +
> + return type;
> +}
> +static void ttm_pool_update_free_locked(struct dma_pool *pool,
> + unsigned freed_pages)
> +{
> + pool->npages_free -= freed_pages;
> + pool->nfrees += freed_pages;
> +
> +}
> +/* set memory back to wb and free the pages. */
> +static void ttm_dma_pages_put(struct dma_pool *pool, struct list_head *d_pages,
> + struct page *pages[], unsigned npages)
> +{
> + struct dma_page *d_page, *tmp;
> +
> + if (npages && set_pages_array_wb(pages, npages))
> + pr_err(TTM_PFX "%s: Failed to set %d pages to wb!\n",
> + pool->dev_name, npages);
> +
> + if (npages > 1) {
> + pr_debug("%s: (%s:%d) Freeing %d pages at once (lockless).\n",
> + pool->dev_name, pool->name, current->pid, npages);
> + }
> +
> + list_for_each_entry_safe(d_page, tmp, d_pages, page_list) {
> + list_del(&d_page->page_list);
> + __ttm_dma_free_page(pool, d_page);
> + }
> +}
> +/*
> + * 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
> + * @nr_free: If set to true will free all pages in pool
> + **/
> +static unsigned ttm_dma_page_pool_free(struct dma_pool *pool, unsigned nr_free)
> +{
> + unsigned long irq_flags;
> + struct dma_page *dma_p, *tmp;
> + struct page **pages_to_free;
> + struct list_head d_pages;
> + unsigned freed_pages = 0,
> + npages_to_free = nr_free;
> +
> + if (NUM_PAGES_TO_ALLOC < nr_free)
> + npages_to_free = NUM_PAGES_TO_ALLOC;
> +#if 0
> + if (nr_free > 1) {
> + pr_debug("%s: (%s:%d) Attempting to free %d (%d) pages\n",
> + pool->dev_name, pool->name, current->pid,
> + npages_to_free, nr_free);
> + }
> +#endif
> + pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
> + GFP_KERNEL);
> +
> + if (!pages_to_free) {
> + pr_err(TTM_PFX
> + "%s: Failed to allocate memory for pool free operation.\n",
> + pool->dev_name);
> + return 0;
> + }
> + INIT_LIST_HEAD(&d_pages);
> +restart:
> + spin_lock_irqsave(&pool->lock, irq_flags);
> +
> + /* We picking the oldest ones off the list */
> + list_for_each_entry_safe_reverse(dma_p, tmp, &pool->free_list,
> + page_list) {
> + if (freed_pages >= npages_to_free)
> + break;
> +
> + /* Move the dma_page from one list to another. */
> + list_move(&dma_p->page_list, &d_pages);
> +
> + pages_to_free[freed_pages++] = dma_p->p;
> + /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
> + if (freed_pages >= NUM_PAGES_TO_ALLOC) {
> +
> + 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_dma_pages_put(pool, &d_pages, pages_to_free,
> + freed_pages);
> +
> + INIT_LIST_HEAD(&d_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 through 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) {
> + ttm_pool_update_free_locked(pool, freed_pages);
> + nr_free -= freed_pages;
> + }
> +
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> +
> + if (freed_pages)
> + ttm_dma_pages_put(pool, &d_pages, pages_to_free, freed_pages);
> +out:
> + kfree(pages_to_free);
> + return nr_free;
> +}
> +
> +static void ttm_dma_free_pool(struct device *dev, enum pool_type type)
> +{
> + struct device_pools *p;
> + struct dma_pool *pool;
> + struct dma_page *d_page, *d_tmp;
> +
> + if (!dev)
> + return;
> +
> + mutex_lock(&_manager->lock);
> + list_for_each_entry_reverse(p, &_manager->pools, pools) {
> + if (p->dev != dev)
> + continue;
> + pool = p->pool;
> + if (pool->type != type)
> + continue;
> +
> + list_del(&p->pools);
> + kfree(p);
> + _manager->npools--;
> + break;
> + }
> + list_for_each_entry_reverse(pool, &dev->dma_pools, pools) {
> + unsigned long irq_save;
> + if (pool->type != type)
> + continue;
> + /* Takes a spinlock.. */
> + ttm_dma_page_pool_free(pool, FREE_ALL_PAGES);
> + /* .. but afterwards we can take it too */
> + spin_lock_irqsave(&pool->lock, irq_save);
> + list_for_each_entry_safe(d_page, d_tmp, &pool->inuse_list,
> + page_list) {
> + pr_err("%s: (%s:%d) %p (%p DMA:0x%lx) busy!\n",
> + pool->dev_name, pool->name,
> + current->pid, d_page->vaddr,
> + virt_to_page(d_page->vaddr),
> + (unsigned long)d_page->dma);
> + list_del(&d_page->page_list);
> + kfree(d_page);
> + pool->npages_in_use--;
> + }
> + spin_unlock_irqrestore(&pool->lock, irq_save);
> + WARN_ON(((pool->npages_in_use + pool->npages_free) != 0));
> + /* This code path is called after _all_ references to the
> + * struct device has been dropped - so nobody should be
> + * touching it. In case somebody is trying to _add_ we are
> + * guarded by the mutex. */
> + list_del(&pool->pools);
> + kfree(pool);
> + break;
> + }
> + mutex_unlock(&_manager->lock);
> +}
> +/*
> + * On free-ing of the 'struct device' this deconstructor is run.
> + * Albeit the pool might have already been freed earlier.
> + */
> +static void ttm_dma_pool_release(struct device *dev, void *res)
> +{
> + struct dma_pool *pool = *(struct dma_pool **)res;
> +
> + if (pool)
> + ttm_dma_free_pool(dev, pool->type);
> +}
> +
> +static int ttm_dma_pool_match(struct device *dev, void *res, void *match_data)
> +{
> + return *(struct dma_pool **)res == match_data;
> +}
> +
> +static struct dma_pool *ttm_dma_pool_init(struct device *dev, gfp_t flags,
> + enum pool_type type)
> +{
> + char *n[] = {"wc", "uc", "cached", " dma32", "unknown",};
> + enum pool_type t[] = {IS_WC, IS_UC, IS_CACHED, IS_DMA32, IS_UNDEFINED};
> + struct device_pools *sec_pool = NULL;
> + struct dma_pool *pool = NULL, **ptr;
> + unsigned i;
> + int ret = -ENODEV;
> + char *p;
> +
> + if (!dev)
> + return NULL;
> +
> + ptr = devres_alloc(ttm_dma_pool_release, sizeof(*ptr), GFP_KERNEL);
> + if (!ptr)
> + return NULL;
> +
> + ret = -ENOMEM;
> +
> + pool = kmalloc_node(sizeof(struct dma_pool), GFP_KERNEL,
> + dev_to_node(dev));
> + if (!pool)
> + goto err_mem;
> +
> + sec_pool = kmalloc_node(sizeof(struct device_pools), GFP_KERNEL,
> + dev_to_node(dev));
> + if (!sec_pool)
> + goto err_mem;
> +
> + INIT_LIST_HEAD(&sec_pool->pools);
> + sec_pool->dev = dev;
> + sec_pool->pool = pool;
> +
> + INIT_LIST_HEAD(&pool->free_list);
> + INIT_LIST_HEAD(&pool->inuse_list);
> + INIT_LIST_HEAD(&pool->pools);
> + spin_lock_init(&pool->lock);
> + pool->dev = dev;
> + pool->npages_free = pool->npages_in_use = 0;
> + pool->nfrees = 0;
> + pool->gfp_flags = flags;
> + pool->size = PAGE_SIZE;
> + pool->type = type;
> + pool->nrefills = 0;
> + pool->fill_lock = false;
> + p = pool->name;
> + for (i = 0; i < 5; i++) {
> + if (type & t[i]) {
> + p += snprintf(p, sizeof(pool->name) - (p - pool->name),
> + "%s", n[i]);
> + }
> + }
> + *p = 0;
> + /* We copy the name for pr_ calls b/c when dma_pool_destroy is called
> + * - the kobj->name has already been deallocated.*/
> + snprintf(pool->dev_name, sizeof(pool->dev_name), "%s %s",
> + dev_driver_string(dev), dev_name(dev));
> + mutex_lock(&_manager->lock);
> + /* You can get the dma_pool from either the global: */
> + list_add(&sec_pool->pools, &_manager->pools);
> + _manager->npools++;
> + /* or from 'struct device': */
> + list_add(&pool->pools, &dev->dma_pools);
> + mutex_unlock(&_manager->lock);
> +
> + *ptr = pool;
> + devres_add(dev, ptr);
> +
> + return pool;
> +err_mem:
> + devres_free(ptr);
> + kfree(sec_pool);
> + kfree(pool);
> + return ERR_PTR(ret);
> +}
> +static struct dma_pool *ttm_dma_find_pool(struct device *dev,
> + enum pool_type type)
> +{
> + struct dma_pool *pool, *tmp, *found = NULL;
> +
> + if (type == IS_UNDEFINED)
> + return found;
> + /* NB: We iterate on the 'struct dev' which has no spinlock, but
> + * it does have a kref which we have taken. */
I fail to see where we kref dev.
> + list_for_each_entry_safe(pool, tmp, &dev->dma_pools, pools) {
> + if (pool->type != type)
> + continue;
> + found = pool;
> + break;
> + }
> + return found;
> +}
> +
> +/*
> + * Free pages the pages that failed to change the caching state. If there
> + * are pages that have changed their caching state already put them to the
> + * pool.
> + */
> +static void ttm_dma_handle_caching_state_failure(struct dma_pool *pool,
> + struct list_head *d_pages,
> + struct page **failed_pages,
> + unsigned cpages)
> +{
> + struct dma_page *d_page, *tmp;
> + struct page *p;
> + unsigned i = 0;
> +
> + p = failed_pages[0];
> + if (!p)
> + return;
> + /* Find the failed page. */
> + list_for_each_entry_safe(d_page, tmp, d_pages, page_list) {
> + if (d_page->p != p)
> + continue;
> + /* .. and then progress over the full list. */
> + list_del(&d_page->page_list);
> + __ttm_dma_free_page(pool, d_page);
> + if (++i < cpages)
> + p = failed_pages[i];
> + else
> + break;
> + }
> +
> +}
> +/*
> + * Allocate 'count' pages, and put 'need' number of them on the
> + * 'pages' and as well on the 'dma_address' starting at 'dma_offset' offset.
> + * The full list of pages should also be on 'd_pages'.
> + * We return zero for success, and negative numbers as errors.
> + */
> +static int ttm_dma_pool_alloc_new_pages(struct dma_pool *pool,
> + struct list_head *d_pages,
> + unsigned count)
> +{
> + struct page **caching_array;
> + struct dma_page *dma_p;
> + 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) {
> + pr_err(TTM_PFX
> + "%s: Unable to allocate table for new pages.",
> + pool->dev_name);
> + return -ENOMEM;
> + }
> +
> + if (count > 1) {
> + pr_debug("%s: (%s:%d) Getting %d pages\n",
> + pool->dev_name, pool->name, current->pid,
> + count);
> + }
> +
> + for (i = 0, cpages = 0; i < count; ++i) {
> + dma_p = __ttm_dma_alloc_page(pool);
> + if (!dma_p) {
> + pr_err(TTM_PFX "%s: Unable to get page %u.\n",
> + pool->dev_name, i);
> +
> + /* store already allocated pages in the pool after
> + * setting the caching state */
> + if (cpages) {
> + r = ttm_set_pages_caching(pool, caching_array,
> + cpages);
> + if (r)
> + ttm_dma_handle_caching_state_failure(
> + pool, d_pages, caching_array,
> + cpages);
> + }
> + r = -ENOMEM;
> + goto out;
> + }
> + p = dma_p->p;
> +#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) {
> + /* Note: Cannot hold the spinlock */
> + r = ttm_set_pages_caching(pool, caching_array,
> + cpages);
> + if (r) {
> + ttm_dma_handle_caching_state_failure(
> + pool, d_pages, caching_array,
> + cpages);
> + goto out;
> + }
> + cpages = 0;
> + }
> + }
> + list_add(&dma_p->page_list, d_pages);
> + }
> +
> + if (cpages) {
> + r = ttm_set_pages_caching(pool, caching_array, cpages);
> + if (r)
> + ttm_dma_handle_caching_state_failure(pool, d_pages,
> + caching_array, cpages);
> + }
> +out:
> + kfree(caching_array);
> + return r;
> +}
> +static bool ttm_dma_iterate_reverse(struct dma_pool *pool,
> + struct dma_page *d_page,
> + struct page *p)
> +{
> +
> + /* Note: When TTM layer gets pages - it gets them one page at a time
> + * and puts them on an array (so most recently allocated page is at
> + * at the back). The inuse_list is a copy of those pages, but in the
> + * exact opposite order. This is b/c when TTM puts pages back, it
> + * constructs a stack with the oldest element on the top. Hence the
> + * inuse_list is constructed with the same order so that it will
> + * efficiently be matched against the stack.
> + * But, just in case the pages are not in that order, we double check
> + * the 'pages' against our inuse_list in case we have to go in reverse.
> + */
> + struct page *p_next;
> + struct dma_page *tmp;
> +
> + tmp = list_entry(d_page->page_list.prev, struct dma_page, page_list);
> + if (&tmp->page_list != &pool->inuse_list) {
> + p_next = list_entry(p->lru.next, struct page, lru);
> + if (tmp->p == p_next)
> + return true;
> + }
> + return false;
> +}
> +
> +/*
> + * Iterate forward (or backwards if 'reverse' is true) by one element
> + * in the pool->in_use list. We use 'd_page' as the starting point.
> + * The 'd_page' upon completion of the iteration, is moved to the
> + * 'd_pages' list.
> + */
> +static struct dma_page *ttm_dma_iterate_next(struct dma_pool *pool,
> + struct dma_page *d_page,
> + struct list_head *d_pages,
> + bool reverse)
> +{
> + struct dma_page *next = NULL;
> +
> + if (unlikely(reverse)) {
> + if (&d_page->page_list != &pool->inuse_list)
> + next = list_entry(d_page->page_list.prev,
> + struct dma_page,
> + page_list);
> + list_move(&d_page->page_list, d_pages);
> + } else {
> + if (&d_page->page_list != &pool->inuse_list)
> + next = list_entry(d_page->page_list.next,
> + struct dma_page,
> + page_list);
> + list_move_tail(&d_page->page_list, d_pages);
> + }
> + return next;
> +}
> +/*
> + * Iterate forward (or backwards if 'reverse' is true), looking
> + * for page 'p' in the pool->inuse_list, starting at 'start'.
> + */
> +static struct dma_page *ttm_dma_iterate_forward(struct dma_pool *pool,
> + struct dma_page *start,
> + struct page *p,
> + bool reverse)
> +{
> + struct dma_page *tmp = start;
> +
> + if (unlikely(reverse)) {
> + list_for_each_entry_continue_reverse(tmp, &pool->inuse_list,
> + page_list) {
> + if (p == tmp->p)
> + return tmp;
> + }
> + } else {
> + list_for_each_entry_continue(tmp, &pool->inuse_list,
> + page_list) {
> + if (p == tmp->p)
> + return tmp;
> + }
> + }
> + return NULL;
> +}
> +/*
> + * Recycle (or delete) the 'pages' that are on the 'pool'.
> + * @pool: The pool that the pages are associated with.
> + * @pages: The list of pages we are done with.
> + * @page_count: Count of how many pages (or zero if all).
> + * @erase: Instead of recycling - just free them.
> + */
> +static unsigned int ttm_dma_put_pages_in_pool(struct dma_pool *pool,
> + struct list_head *pages,
> + unsigned page_count,
> + bool erase)
> +{
> + unsigned long uninitialized_var(irq_flags);
> + struct list_head uninitialized_var(d_pages);
> + struct page **uninitialized_var(array_pages);
> + unsigned uninitialized_var(freed_pages);
> + struct page *p, *tmp;
> + unsigned count = 0;
> + struct dma_page *d_tmp, *d_page = NULL;
> + bool rev = false;
> + if (unlikely(WARN_ON(list_empty(pages))))
> + return 0;
> +
> + if (page_count == 0) {
> + list_for_each_entry(p, pages, lru)
> + ++page_count;
> +
> + }
> + if (page_count > 1) {
> + pr_debug("%s: (%s:%d) %s %d pages\n",
> + pool->dev_name, pool->name, current->pid,
> + erase ? "Destroying" : "Recycling", page_count);
> + }
> +
> + /* d_pages is the list of 'struct dma_page' */
> + INIT_LIST_HEAD(&d_pages);
> +
> + if (erase) {
> + /* and pages_to_free is used for cache reset */
> + array_pages = kmalloc(page_count * sizeof(struct page *),
> + GFP_KERNEL);
> + if (!array_pages) {
> + dev_err(pool->dev, TTM_PFX
> + "Failed to allocate memory for pool free operation.\n");
> + return 0;
> + }
> + freed_pages = 0;
> + }
> +
> + /* Find the first page of the "chunk" of pages. */
> + p = list_first_entry(pages, struct page, lru);
> + spin_lock_irqsave(&pool->lock, irq_flags);
> +restart:
> + list_for_each_entry(d_tmp, &pool->inuse_list, page_list) {
> + if (p == d_tmp->p) {
> + d_page = d_tmp;
> + break;
> + }
> + }
> + /* The pages are _not_ in this pool. */
> + if (!d_page) {
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> + return 0;
> + }
> + rev = ttm_dma_iterate_reverse(pool, d_page, p);
> + if (rev)
> + pr_debug("%s: (%s:%d) Traversing %d in reverse order\n",
> + pool->dev_name, pool->name, current->pid, page_count);
> + /* Continue iterating on both lists. */
> + list_for_each_entry_safe(p, tmp, pages, lru) {
> + if (d_page->p != p && count != page_count) {
> + /* Yikes! The inuse stack is swiss cheese. Have to
> + start looking.*/
> + d_page = ttm_dma_iterate_forward(pool, d_page, p, rev);
> + if (!d_page)
> + goto restart;
> + }
> + /* Do not advance past what we were asked to delete. */
> + if (d_page->p != p)
> + break;
> + list_del(&p->lru);
> +
> + if (erase)
> + array_pages[freed_pages++] = d_page->p;
> + d_page = ttm_dma_iterate_next(pool, d_page, &d_pages, rev);
> + if (!d_page)
> + break;
> + count++;
> + /* Check if we should iterate. */
> + if (count == page_count)
> + break;
> + }
> + if (!erase) /* And stick 'em on the free pool. */
> + list_splice(&d_pages, &pool->free_list);
> +
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> +
> + if (erase) {
> + /* Note: The caller of us updates the pool accounting. */
> + ttm_dma_pages_put(pool, &d_pages, array_pages /* to set WB */,
> + freed_pages);
> + kfree(array_pages);
> + }
> + if (count > 1) {
> + pr_debug("%s: (%s:%d) %d/%d pages %s pool.\n",
> + pool->dev_name, pool->name, current->pid,
> + count, page_count,
> + erase ? "erased from inuse" : "put in free");
> + }
> + return count;
> +}
> +/*
> + * @return count of pages still required to fulfill the request.
> +*/
> +static int ttm_dma_page_pool_fill_locked(struct dma_pool *pool,
> + unsigned count,
> + unsigned long *irq_flags)
> +{
> + int r = count;
> +
> + if (pool->fill_lock)
> + return r;
> +
> + pool->fill_lock = true;
> + if (count < _manager->options.small &&
> + count > pool->npages_free) {
> + struct list_head d_pages;
> + unsigned alloc_size = _manager->options.alloc_size;
> +
> + INIT_LIST_HEAD(&d_pages);
> +
> + spin_unlock_irqrestore(&pool->lock, *irq_flags);
> +
> + /* Returns how many more are neccessary to fulfill the
> + * request. */
> + r = ttm_dma_pool_alloc_new_pages(pool, &d_pages, alloc_size);
> +
> + spin_lock_irqsave(&pool->lock, *irq_flags);
> + if (!r) {
> + /* Add the fresh to the end.. */
> + list_splice(&d_pages, &pool->free_list);
> + ++pool->nrefills;
> + pool->npages_free += alloc_size;
> + } else {
> + struct dma_page *d_page;
> + unsigned cpages = 0;
> +
> + pr_err(TTM_PFX "%s: Failed to fill %s pool (r:%d)!\n",
> + pool->dev_name, pool->name, r);
> +
> + list_for_each_entry(d_page, &d_pages, page_list) {
> + cpages++;
> + }
> + list_splice_tail(&d_pages, &pool->free_list);
> + pool->npages_free += cpages;
> + }
> + }
> + pool->fill_lock = false;
> + return r;
> +
> +}
> +
> +/*
> + * @return count of pages still required to fulfill the request.
> + * The populate list is actually a stack (not that is matters as TTM
> + * allocates one page at a time.
> + */
> +static int ttm_dma_pool_get_pages(struct dma_pool *pool,
> + struct list_head *pages,
> + dma_addr_t *dma_address, unsigned count)
> +{
> + unsigned long irq_flags;
> + int r;
> + unsigned i;
> + struct dma_page *d_page, *tmp;
> + struct list_head d_pages;
> +
> + spin_lock_irqsave(&pool->lock, irq_flags);
> + r = ttm_dma_page_pool_fill_locked(pool, count, &irq_flags);
> + if (r < 0) {
> + pr_debug("%s: (%s:%d) Asked for %d, got %d %s.\n",
> + pool->dev_name, pool->name, current->pid, count, r,
> + (r < 0) ? "err:" : "pages");
> + goto out;
> + }
> + if (!pool->npages_free)
> + goto out;
> + if (count > 1) {
> + pr_debug("%s: (%s:%d) Looking in free list for %d pages. "\
> + "(have %d pages free)\n",
> + pool->dev_name, pool->name, current->pid, count,
> + pool->npages_free);
> + }
> + i = 0;
> + /* We are holding the spinlock.. */
> + INIT_LIST_HEAD(&d_pages);
> + /* Note: The the 'pages' (and inuse_list) is expected to be a stack,
> + * so we put the entries in the right order (and on the inuse list
> + * in the reverse order to compenstate for freeing - which inverts the
> + * 'pages' order).
> + */
> + list_for_each_entry_safe(d_page, tmp, &pool->free_list, page_list) {
> + list_add_tail(&d_page->p->lru, pages);
> + dma_address[i++] = d_page->dma;
> + list_move(&d_page->page_list, &d_pages);
> + if (i == count)
> + break;
> + }
> + /* Note: The 'inuse_list' must have the same order as the 'pages'
> + * to be effective when pages are put back. And since 'pages' is
> + * as stack, ergo inuse_list is a stack too. */
> + list_splice(&d_pages, &pool->inuse_list);
> + count -= i;
> + pool->npages_in_use += i;
> + pool->npages_free -= i;
> +out:
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> + if (count)
> + pr_debug("%s: (%s:%d) Need %d more.\n",
> + pool->dev_name, pool->name, current->pid, count);
> + return count;
> +}
> +/*
> + * On success pages list will hold count number of correctly
> + * cached pages. On failure will hold the negative return value (-ENOMEM, etc).
> + */
> +int ttm_dma_get_pages(struct ttm_tt *ttm, struct list_head *pages,
> + unsigned count, dma_addr_t *dma_address)
> +
> +{
> + int r = -ENOMEM;
> + struct dma_pool *pool;
> + gfp_t gfp_flags;
> + enum pool_type type;
> + struct device *dev = ttm->be->dev;
> +
> + type = ttm_to_type(ttm->page_flags, ttm->caching_state);
> +
> + if (ttm->page_flags & TTM_PAGE_FLAG_DMA32)
> + gfp_flags = GFP_USER | GFP_DMA32;
> + else
> + gfp_flags = GFP_HIGHUSER;
> +
> + if (ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
> + gfp_flags |= __GFP_ZERO;
> +
> + pool = ttm_dma_find_pool(dev, type);
> + if (!pool) {
> + pool = ttm_dma_pool_init(dev, gfp_flags, type);
> + if (IS_ERR_OR_NULL(pool))
> + return -ENOMEM;
> + }
> +#if 0
> + if (count > 1) {
> + pr_debug("%s (%s:%d) Attempting to get %d pages type %x\n",
> + pool->dev_name, pool->name, current->pid, count,
> + cstate);
> + }
> +#endif
> + /* Take pages out of a pool (if applicable) */
> + r = ttm_dma_pool_get_pages(pool, pages, dma_address, count);
> + /* clear the pages coming from the pool if requested */
> + if (ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
> + struct page *p;
> + list_for_each_entry(p, pages, lru) {
> + clear_page(page_address(p));
> + }
> + }
> + /* If pool didn't have enough pages allocate new one. */
> + if (r > 0) {
> + struct list_head d_pages;
> + unsigned pages_need = r;
> + unsigned long irq_flags;
> +
> + INIT_LIST_HEAD(&d_pages);
> +
> + /* Note, we are running without locking here..
> + * and we have to manually add the stack to the inuse pool. */
> + r = ttm_dma_pool_alloc_new_pages(pool, &d_pages, pages_need);
> +
> + if (r == 0) {
> + struct dma_page *d_page;
> + int i = count - 1;
> +
> + /* Since the pages are directly going to the inuse_list
> + * which is stack based, lets treat it as a stack.
> + */
> + list_for_each_entry(d_page, &d_pages, page_list) {
> + list_add(&d_page->p->lru, pages);
> + BUG_ON(i < 0);
> + dma_address[i--] = d_page->dma;
> + }
> + spin_lock_irqsave(&pool->lock, irq_flags);
> + pool->npages_in_use += pages_need;
> + list_splice(&d_pages, &pool->inuse_list);
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> + } else {
> + /* If there is any pages in the list put them back to
> + * the pool. */
> + pr_err(TTM_PFX
> + "%s: Failed to allocate extra pages "
> + "for large request.",
> + pool->dev_name);
> + spin_lock_irqsave(&pool->lock, irq_flags);
> + pool->npages_free += r;
> + /* We don't care about ordering on the free_list. */
> + list_splice(&d_pages, &pool->free_list);
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> + return count;
> + }
> + }
> + return r;
> +}
> +
> +/* Get good estimation how many pages are free in pools */
> +static int ttm_dma_pool_get_num_unused_pages(void)
> +{
> + struct device_pools *p;
> + unsigned total = 0;
> +
> + mutex_lock(&_manager->lock);
> + list_for_each_entry(p, &_manager->pools, pools) {
> + if (p)
> + total += p->pool->npages_free;
> + }
> + mutex_unlock(&_manager->lock);
> + return total;
> +}
> +
> +/* Put all pages in pages list to correct pool to wait for reuse */
> +void ttm_dma_put_pages(struct ttm_tt *ttm, struct list_head *pages,
> + unsigned page_count, dma_addr_t *dma_address)
> +{
> + struct dma_pool *pool;
> + enum pool_type type;
> + bool is_cached = false;
> + unsigned count = 0, i;
> + unsigned long irq_flags;
> + struct device *dev = ttm->be->dev;
> +
> + if (list_empty(pages))
> + return;
> +
> + type = ttm_to_type(ttm->page_flags, ttm->caching_state);
> + pool = ttm_dma_find_pool(dev, type);
> + if (!pool) {
> + WARN_ON(!pool);
> + return;
> + }
> + is_cached = (ttm_dma_find_pool(pool->dev,
> + ttm_to_type(ttm->page_flags, tt_cached)) == pool);
> +
> + if (page_count > 1) {
> + dev_dbg(pool->dev, "(%s:%d) Attempting to %s %d pages.\n",
> + pool->name, current->pid,
> + (is_cached) ? "destroy" : "recycle", page_count);
> + }
> +
> + count = ttm_dma_put_pages_in_pool(pool, pages, page_count, is_cached);
> +
> + for (i = 0; i < count; i++)
> + dma_address[i] = 0;
> +
> + spin_lock_irqsave(&pool->lock, irq_flags);
> + pool->npages_in_use -= count;
> + if (is_cached)
> + pool->nfrees += count;
> + else
> + pool->npages_free += count;
> + spin_unlock_irqrestore(&pool->lock, irq_flags);
> +
> + page_count -= count;
> + WARN(page_count != 0,
> + "Only freed %d page(s) in %s. Could not free the other %d!\n",
> + count, pool->name, page_count);
> +
> + page_count = 0;
> + if (pool->npages_free > _manager->options.max_size) {
> + page_count = pool->npages_free - _manager->options.max_size;
> + if (page_count < NUM_PAGES_TO_ALLOC)
> + page_count = NUM_PAGES_TO_ALLOC;
> + }
> + if (page_count)
> + ttm_dma_page_pool_free(pool, page_count);
> +}
> +
> +/**
> + * Callback for mm to request pool to reduce number of page held.
> + */
> +static int ttm_dma_pool_mm_shrink(struct shrinker *shrink,
> + struct shrink_control *sc)
> +{
> + static atomic_t start_pool = ATOMIC_INIT(0);
> + unsigned idx = 0;
> + unsigned pool_offset = atomic_add_return(1, &start_pool);
> + unsigned shrink_pages = sc->nr_to_scan;
> + struct device_pools *p;
> +
> + if (list_empty(&_manager->pools))
> + return 0;
> +
> + mutex_lock(&_manager->lock);
> + pool_offset = pool_offset % _manager->npools;
> + list_for_each_entry(p, &_manager->pools, pools) {
> + unsigned nr_free;
> +
> + if (!p && !p->dev)
> + continue;
> + if (shrink_pages == 0)
> + break;
> + /* Do it in round-robin fashion. */
> + if (++idx < pool_offset)
> + continue;
> + nr_free = shrink_pages;
> + shrink_pages = ttm_dma_page_pool_free(p->pool, nr_free);
> + pr_debug("%s: (%s:%d) Asked to shrink %d, have %d more to go\n",
> + p->pool->dev_name, p->pool->name, current->pid, nr_free,
> + shrink_pages);
> + }
> + mutex_unlock(&_manager->lock);
> + /* return estimated number of unused pages in pool */
> + return ttm_dma_pool_get_num_unused_pages();
> +}
> +
> +static void ttm_dma_pool_mm_shrink_init(struct ttm_pool_manager *manager)
> +{
> + manager->mm_shrink.shrink = &ttm_dma_pool_mm_shrink;
> + manager->mm_shrink.seeks = 1;
> + register_shrinker(&manager->mm_shrink);
> +}
> +static void ttm_dma_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
> +{
> + unregister_shrinker(&manager->mm_shrink);
> +}
> +int ttm_dma_page_alloc_init(struct ttm_mem_global *glob,
> + unsigned max_pages)
> +{
> + int ret = -ENOMEM;
> +
> + WARN_ON(_manager);
> +
> + printk(KERN_INFO TTM_PFX "Initializing DMA pool allocator.\n");
> +
> + _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
> + if (!_manager)
> + goto err_manager;
> +
> + mutex_init(&_manager->lock);
> + INIT_LIST_HEAD(&_manager->pools);
> +
> + _manager->options.max_size = max_pages;
> + _manager->options.small = SMALL_ALLOCATION;
> + _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
> +
> + /* This takes care of auto-freeing the _manager */
> + ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
> + &glob->kobj, "dma_pool");
> + if (unlikely(ret != 0)) {
> + kobject_put(&_manager->kobj);
> + goto err;
> + }
> + ttm_dma_pool_mm_shrink_init(_manager);
> + return 0;
> +err_manager:
> + kfree(_manager);
> + _manager = NULL;
> +err:
> + return ret;
> +}
> +void ttm_dma_page_alloc_fini(void)
> +{
> + struct device_pools *p, *t;
> +
> + printk(KERN_INFO TTM_PFX "Finalizing DMA pool allocator.\n");
> + ttm_dma_pool_mm_shrink_fini(_manager);
> +
> + list_for_each_entry_safe_reverse(p, t, &_manager->pools, pools) {
> + dev_dbg(p->dev, "(%s:%d) Freeing.\n", p->pool->name,
> + current->pid);
> + WARN_ON(devres_destroy(p->dev, ttm_dma_pool_release,
> + ttm_dma_pool_match, p->pool));
> + ttm_dma_free_pool(p->dev, p->pool->type);
> + }
> + kobject_put(&_manager->kobj);
> + _manager = NULL;
> +}
> +
> +int ttm_dma_page_alloc_debugfs(struct seq_file *m, void *data)
> +{
> + struct device_pools *p;
> + struct dma_pool *pool = NULL;
> + char *h[] = {"pool", "refills", "pages freed", "inuse", "available",
> + "name", "virt", "busaddr"};
> +
> + if (!_manager) {
> + seq_printf(m, "No pool allocator running.\n");
> + return 0;
> + }
> + seq_printf(m, "%13s %12s %13s %8s %8s %8s\n",
> + h[0], h[1], h[2], h[3], h[4], h[5]);
> + mutex_lock(&_manager->lock);
> + list_for_each_entry(p, &_manager->pools, pools) {
> + struct device *dev = p->dev;
> + if (!dev)
> + continue;
> + pool = p->pool;
> + seq_printf(m, "%13s %12ld %13ld %8d %8d %8s\n",
> + pool->name, pool->nrefills,
> + pool->nfrees, pool->npages_in_use,
> + pool->npages_free,
> + pool->dev_name);
> + }
> + mutex_unlock(&_manager->lock);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(ttm_dma_page_alloc_debugfs);
> +bool ttm_dma_override(struct ttm_backend_func *be)
> +{
> + if (swiotlb_nr_tbl() && be) {
> + be->get_pages = &ttm_dma_get_pages;
> + be->put_pages = &ttm_dma_put_pages;
> + return true;
> + }
> + return false;
> +}
> +EXPORT_SYMBOL_GPL(ttm_dma_override);
> diff --git a/include/drm/ttm/ttm_page_alloc.h b/include/drm/ttm/ttm_page_alloc.h
> index 0aaac39..9c52fb7 100644
> --- a/include/drm/ttm/ttm_page_alloc.h
> +++ b/include/drm/ttm/ttm_page_alloc.h
> @@ -29,6 +29,37 @@
> #include "ttm_bo_driver.h"
> #include "ttm_memory.h"
>
> +#ifdef CONFIG_SWIOTLB
> +extern bool ttm_dma_override(struct ttm_backend_func *be);
> +
> +/**
> + * Initialize pool allocator.
> + */
> +int ttm_dma_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages);
> +/**
> + * Free pool allocator.
> + */
> +void ttm_dma_page_alloc_fini(void);
> +/**
> + * Output the state of pools to debugfs file
> + */
> +extern int ttm_dma_page_alloc_debugfs(struct seq_file *m, void *data);
> +#else
> +static inline bool ttm_dma_override(struct ttm_backend_func *be)
> +{
> + return false;
> +}
> +static inline int ttm_dma_page_alloc_init(struct ttm_mem_global *glob,
> + unsigned max_pages)
> +{
> + return -ENODEV;
> +}
> +static inline void ttm_dma_page_alloc_fini(void) { return; }
> +static inline int ttm_dma_page_alloc_debugfs(struct seq_file *m, void *data)
> +{
> + return 0;
> +}
> +#endif
> /**
> * Get count number of pages from pool to pages list.
> *
> --
> 1.7.6.4
>
See comment above, otherwise:
Reviewed-by: Jerome Glisse <jglisse@xxxxxxxxxx>
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