[PATCH 1/9] drm/ttm: new TT backend allocation pool v2
Huang Rui
ray.huang at amd.com
Tue Oct 27 12:49:37 UTC 2020
On Mon, Oct 26, 2020 at 06:41:09PM +0100, Christian König wrote:
> This replaces the spaghetti code in the two existing page pools.
>
> First of all depending on the allocation size it is between 3 (1GiB) and
> 5 (1MiB) times faster than the old implementation.
>
> It makes better use of buddy pages to allow for larger physical contiguous
> allocations which should result in better TLB utilization at least for
> amdgpu.
>
> Instead of a completely braindead approach of filling the pool with one
> CPU while another one is trying to shrink it we only give back freed
> pages.
>
> This also results in much less locking contention and a trylock free MM
> shrinker callback, so we can guarantee that pages are given back to the
> system when needed.
>
> Downside of this is that it takes longer for many small allocations until
> the pool is filled up. We could address this, but I couldn't find an use
> case where this actually matters. We also don't bother freeing large
> chunks of pages any more since the CPU overhead in that path isn't really
> that important.
>
> The sysfs files are replaced with a single module parameter, allowing
> users to override how many pages should be globally pooled in TTM. This
> unfortunately breaks the UAPI slightly, but as far as we know nobody ever
> depended on this.
>
> Zeroing memory coming from the pool was handled inconsistently. The
> alloc_pages() based pool was zeroing it, the dma_alloc_attr() based one
> wasn't. For now the new implementation isn't zeroing pages from the pool
> either and only sets the __GFP_ZERO flag when necessary.
>
> The implementation has only 768 lines of code compared to the over 2600
> of the old one, and also allows for saving quite a bunch of code in the
> drivers since we don't need specialized handling there any more based on
> kernel config.
>
> Additional to all of that there was a neat bug with IOMMU, coherent DMA
> mappings and huge pages which is now fixed in the new code as well.
>
> v2: make ttm_pool_apply_caching static as reported by the kernel bot, add
> some more checks
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
> drivers/gpu/drm/ttm/Makefile | 2 +-
> drivers/gpu/drm/ttm/ttm_memory.c | 3 +
> drivers/gpu/drm/ttm/ttm_pool.c | 668 +++++++++++++++++++++++++++++++
> include/drm/ttm/ttm_caching.h | 2 +
> include/drm/ttm/ttm_pool.h | 90 +++++
> 5 files changed, 764 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/ttm/ttm_pool.c
> create mode 100644 include/drm/ttm/ttm_pool.h
>
> diff --git a/drivers/gpu/drm/ttm/Makefile b/drivers/gpu/drm/ttm/Makefile
> index 90c0da88cc98..0096bacbcf32 100644
> --- a/drivers/gpu/drm/ttm/Makefile
> +++ b/drivers/gpu/drm/ttm/Makefile
> @@ -5,7 +5,7 @@
> ttm-y := ttm_memory.o ttm_tt.o ttm_bo.o \
> ttm_bo_util.o ttm_bo_vm.o ttm_module.o \
> ttm_execbuf_util.o ttm_page_alloc.o ttm_range_manager.o \
> - ttm_resource.o
> + ttm_resource.o ttm_pool.o
> ttm-$(CONFIG_AGP) += ttm_agp_backend.o
> ttm-$(CONFIG_DRM_TTM_DMA_PAGE_POOL) += ttm_page_alloc_dma.o
>
> diff --git a/drivers/gpu/drm/ttm/ttm_memory.c b/drivers/gpu/drm/ttm/ttm_memory.c
> index 69cf622e79e5..3012d0388c51 100644
> --- a/drivers/gpu/drm/ttm/ttm_memory.c
> +++ b/drivers/gpu/drm/ttm/ttm_memory.c
> @@ -38,6 +38,7 @@
> #include <linux/module.h>
> #include <linux/slab.h>
> #include <linux/swap.h>
> +#include <drm/ttm/ttm_pool.h>
>
> #define TTM_MEMORY_ALLOC_RETRIES 4
>
> @@ -453,6 +454,7 @@ int ttm_mem_global_init(struct ttm_mem_global *glob)
> }
> 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));
> + ttm_pool_mgr_init(glob->zone_kernel->max_mem/(2*PAGE_SIZE));
> return 0;
> out_no_zone:
> ttm_mem_global_release(glob);
> @@ -467,6 +469,7 @@ 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();
> + ttm_pool_mgr_fini();
>
> flush_workqueue(glob->swap_queue);
> destroy_workqueue(glob->swap_queue);
> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
> new file mode 100644
> index 000000000000..d25712e3ad3b
> --- /dev/null
> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> @@ -0,0 +1,668 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +/*
> + * Copyright 2020 Advanced Micro Devices, 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, sublicense,
> + * 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 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 NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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: Christian König
> + */
> +
> +/* Pooling of allocated pages is necessary because changing the caching
> + * attributes on x86 of the linear mapping requires a costly cross CPU TLB
> + * invalidate for those addresses.
> + *
> + * Additional to that allocations from the DMA coherent API are pooled as well
> + * cause they are rather slow compared to alloc_pages+map.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/dma-mapping.h>
> +
> +#ifdef CONFIG_X86
> +#include <asm/set_memory.h>
> +#endif
> +
> +#include <drm/ttm/ttm_pool.h>
> +#include <drm/ttm/ttm_bo_driver.h>
> +#include <drm/ttm/ttm_tt.h>
> +
> +/**
> + * struct ttm_pool_dma - Helper object for coherent DMA mappings
> + *
> + * @addr: original DMA address returned for the mapping
> + * @vaddr: original vaddr return for the mapping and order in the lower bits
> + */
> +struct ttm_pool_dma {
> + dma_addr_t addr;
> + unsigned long vaddr;
> +};
> +
> +static unsigned long page_pool_size;
> +
> +MODULE_PARM_DESC(page_pool_size, "Number of pages in the WC/UC/DMA pool");
> +module_param(page_pool_size, ulong, 0644);
> +
> +static atomic_long_t allocated_pages;
> +
> +static struct ttm_pool_type global_write_combined[MAX_ORDER];
> +static struct ttm_pool_type global_uncached[MAX_ORDER];
> +
> +static spinlock_t shrinker_lock;
> +static struct list_head shrinker_list;
> +static struct shrinker mm_shrinker;
> +
> +/* Allocate pages of size 1 << order with the given gfp_flags */
> +static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags,
> + unsigned int order)
> +{
> + unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
> + struct ttm_pool_dma *dma;
> + struct page *p;
> + void *vaddr;
> +
> + if (order) {
> + gfp_flags |= GFP_TRANSHUGE_LIGHT | __GFP_NORETRY |
> + __GFP_KSWAPD_RECLAIM;
> + gfp_flags &= ~__GFP_MOVABLE;
> + gfp_flags &= ~__GFP_COMP;
> + }
> +
> + if (!pool->use_dma_alloc) {
> + p = alloc_pages(gfp_flags, order);
> + if (p)
> + p->private = order;
> + return p;
> + }
> +
> + dma = kmalloc(sizeof(*dma), GFP_KERNEL);
> + if (!dma)
> + return NULL;
> +
> + if (order)
> + attr |= DMA_ATTR_NO_WARN;
> +
> + vaddr = dma_alloc_attrs(pool->dev, (1ULL << order) * PAGE_SIZE,
> + &dma->addr, gfp_flags, attr);
> + if (!vaddr)
> + goto error_free;
> +
> + /* TODO: This is an illegal abuse of the DMA API, but we need to rework
> + * TTM page fault handling and extend the DMA API to clean this up.
> + */
> + if (is_vmalloc_addr(vaddr))
> + p = vmalloc_to_page(vaddr);
> + else
> + p = virt_to_page(vaddr);
> +
> + dma->vaddr = (unsigned long)vaddr | order;
> + p->private = (unsigned long)dma;
> + return p;
> +
> +error_free:
> + kfree(dma);
> + return NULL;
> +}
> +
> +/* Reset the caching and pages of size 1 << order */
> +static void ttm_pool_free_page(struct ttm_pool *pool, enum ttm_caching caching,
> + unsigned int order, struct page *p)
> +{
> + unsigned long attr = DMA_ATTR_FORCE_CONTIGUOUS;
> + struct ttm_pool_dma *dma;
> + void *vaddr;
> +
> +#ifdef CONFIG_X86
> + /* We don't care that set_pages_wb is inefficient here. This is only
> + * used when we have to shrink and CPU overhead is irrelevant then.
> + */
> + if (caching != ttm_cached && !PageHighMem(p))
> + set_pages_wb(p, 1 << order);
> +#endif
> +
> + if (!pool->use_dma_alloc) {
> + __free_pages(p, order);
> + return;
> + }
> +
> + if (order)
> + attr |= DMA_ATTR_NO_WARN;
> +
> + dma = (void *)p->private;
> + vaddr = (void *)(dma->vaddr & PAGE_MASK);
> + dma_free_attrs(pool->dev, (1UL << order) * PAGE_SIZE, vaddr, dma->addr,
> + attr);
> + kfree(dma);
> +}
> +
> +/* Apply a new caching to an array of pages */
> +static int ttm_pool_apply_caching(struct page **first, struct page **last,
> + enum ttm_caching caching)
> +{
> +#ifdef CONFIG_X86
> + unsigned int num_pages = last - first;
> +
> + if (!num_pages)
> + return 0;
> +
> + switch (caching) {
> + case ttm_cached:
> + break;
> + case ttm_write_combined:
> + return set_pages_array_wc(first, num_pages);
> + case ttm_uncached:
> + return set_pages_array_uc(first, num_pages);
> + }
Do we take care of legacy AGP interfaces?
Thanks,
Ray
> +#endif
> + return 0;
> +}
> +
> +/* Map pages of 1 << order size and fill the DMA address array */
> +static int ttm_pool_map(struct ttm_pool *pool, unsigned int order,
> + struct page *p, dma_addr_t **dma_addr)
> +{
> + dma_addr_t addr;
> + unsigned int i;
> +
> + if (pool->use_dma_alloc) {
> + struct ttm_pool_dma *dma = (void *)p->private;
> +
> + addr = dma->addr;
> + } else {
> + size_t size = (1ULL << order) * PAGE_SIZE;
> +
> + addr = dma_map_page(pool->dev, p, 0, size, DMA_BIDIRECTIONAL);
> + if (dma_mapping_error(pool->dev, **dma_addr))
> + return -EFAULT;
> + }
> +
> + for (i = 1 << order; i ; --i) {
> + *(*dma_addr)++ = addr;
> + addr += PAGE_SIZE;
> + }
> +
> + return 0;
> +}
> +
> +/* Unmap pages of 1 << order size */
> +static void ttm_pool_unmap(struct ttm_pool *pool, dma_addr_t dma_addr,
> + unsigned int num_pages)
> +{
> + /* Unmapped while freeing the page */
> + if (pool->use_dma_alloc)
> + return;
> +
> + dma_unmap_page(pool->dev, dma_addr, (long)num_pages << PAGE_SHIFT,
> + DMA_BIDIRECTIONAL);
> +}
> +
> +/* Give pages into a specific pool_type */
> +static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p)
> +{
> + spin_lock(&pt->lock);
> + list_add(&p->lru, &pt->pages);
> + spin_unlock(&pt->lock);
> + atomic_long_add(1 << pt->order, &allocated_pages);
> +}
> +
> +/* Take pages from a specific pool_type, return NULL when nothing available */
> +static struct page *ttm_pool_type_take(struct ttm_pool_type *pt)
> +{
> + struct page *p;
> +
> + spin_lock(&pt->lock);
> + p = list_first_entry_or_null(&pt->pages, typeof(*p), lru);
> + if (p) {
> + atomic_long_sub(1 << pt->order, &allocated_pages);
> + list_del(&p->lru);
> + }
> + spin_unlock(&pt->lock);
> +
> + return p;
> +}
> +
> +/* Count the number of pages available in a pool_type */
> +static unsigned int ttm_pool_type_count(struct ttm_pool_type *pt)
> +{
> + unsigned int count = 0;
> + struct page *p;
> +
> + spin_lock(&pt->lock);
> + /* Only used for debugfs, the overhead doesn't matter */
> + list_for_each_entry(p, &pt->pages, lru)
> + ++count;
> + spin_unlock(&pt->lock);
> +
> + return count;
> +}
> +
> +/* Initialize and add a pool type to the global shrinker list */
> +static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool,
> + enum ttm_caching caching, unsigned int order)
> +{
> + pt->pool = pool;
> + pt->caching = caching;
> + pt->order = order;
> + spin_lock_init(&pt->lock);
> + INIT_LIST_HEAD(&pt->pages);
> +
> + spin_lock(&shrinker_lock);
> + list_add_tail(&pt->shrinker_list, &shrinker_list);
> + spin_unlock(&shrinker_lock);
> +}
> +
> +/* Remove a pool_type from the global shrinker list and free all pages */
> +static void ttm_pool_type_fini(struct ttm_pool_type *pt)
> +{
> + struct page *p, *tmp;
> +
> + spin_lock(&shrinker_lock);
> + list_del(&pt->shrinker_list);
> + spin_unlock(&shrinker_lock);
> +
> + list_for_each_entry_safe(p, tmp, &pt->pages, lru)
> + ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
> +}
> +
> +/* Return the pool_type to use for the given caching and order */
> +static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool,
> + enum ttm_caching caching,
> + unsigned int order)
> +{
> + if (pool->use_dma_alloc)
> + return &pool->caching[caching].orders[order];
> +
> +#ifdef CONFIG_X86
> + switch (caching) {
> + case ttm_write_combined:
> + return &global_write_combined[order];
> + case ttm_uncached:
> + return &global_uncached[order];
> + default:
> + break;
> + }
> +#endif
> +
> + return NULL;
> +}
> +
> +/* Free pages using the global shrinker list */
> +static unsigned int ttm_pool_shrink(void)
> +{
> + struct ttm_pool_type *pt;
> + unsigned int num_freed;
> + struct page *p;
> +
> + spin_lock(&shrinker_lock);
> + pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list);
> +
> + p = ttm_pool_type_take(pt);
> + if (p) {
> + ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
> + num_freed = 1 << pt->order;
> + } else {
> + num_freed = 0;
> + }
> +
> + list_move_tail(&pt->shrinker_list, &shrinker_list);
> + spin_unlock(&shrinker_lock);
> +
> + return num_freed;
> +}
> +
> +/* Return the allocation order based for a page */
> +static unsigned int ttm_pool_page_order(struct ttm_pool *pool, struct page *p)
> +{
> + if (pool->use_dma_alloc) {
> + struct ttm_pool_dma *dma = (void *)p->private;
> +
> + return dma->vaddr & ~PAGE_MASK;
> + }
> +
> + return p->private;
> +}
> +
> +/**
> + * ttm_pool_alloc - Fill a ttm_tt object
> + *
> + * @pool: ttm_pool to use
> + * @tt: ttm_tt object to fill
> + * @ctx: operation context
> + *
> + * Fill the ttm_tt object with pages and also make sure to DMA map them when
> + * necessary.
> + *
> + * Returns: 0 on successe, negative error code otherwise.
> + */
> +int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
> + struct ttm_operation_ctx *ctx)
> +{
> + unsigned long num_pages = tt->num_pages;
> + dma_addr_t *dma_addr = tt->dma_address;
> + struct page **caching = tt->pages;
> + struct page **pages = tt->pages;
> + gfp_t gfp_flags = GFP_USER;
> + unsigned int i, order;
> + struct page *p;
> + int r;
> +
> + WARN_ON(!num_pages || ttm_tt_is_populated(tt));
> + WARN_ON(dma_addr && !pool->dev);
> +
> + if (tt->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
> + gfp_flags |= __GFP_ZERO;
> +
> + if (tt->page_flags & TTM_PAGE_FLAG_NO_RETRY)
> + gfp_flags |= __GFP_RETRY_MAYFAIL;
> +
> + if (pool->use_dma32)
> + gfp_flags |= GFP_DMA32;
> + else
> + gfp_flags |= GFP_HIGHUSER;
> +
> + for (order = min(MAX_ORDER - 1UL, __fls(num_pages)); num_pages;
> + order = min_t(unsigned int, order, __fls(num_pages))) {
> + bool apply_caching = false;
> + struct ttm_pool_type *pt;
> +
> + pt = ttm_pool_select_type(pool, tt->caching, order);
> + p = pt ? ttm_pool_type_take(pt) : NULL;
> + if (p) {
> + apply_caching = true;
> + } else {
> + p = ttm_pool_alloc_page(pool, gfp_flags, order);
> + if (p && PageHighMem(p))
> + apply_caching = true;
> + }
> +
> + if (!p) {
> + if (order) {
> + --order;
> + continue;
> + }
> + r = -ENOMEM;
> + goto error_free_all;
> + }
> +
> + if (apply_caching) {
> + r = ttm_pool_apply_caching(caching, pages,
> + tt->caching);
> + if (r)
> + goto error_free_page;
> + caching = pages + (1 << order);
> + }
> +
> + r = ttm_mem_global_alloc_page(&ttm_mem_glob, p,
> + (1 << order) * PAGE_SIZE,
> + ctx);
> + if (r)
> + goto error_free_page;
> +
> + if (dma_addr) {
> + r = ttm_pool_map(pool, order, p, &dma_addr);
> + if (r)
> + goto error_global_free;
> + }
> +
> + num_pages -= 1 << order;
> + for (i = 1 << order; i; --i)
> + *(pages++) = p++;
> + }
> +
> + r = ttm_pool_apply_caching(caching, pages, tt->caching);
> + if (r)
> + goto error_free_all;
> +
> + return 0;
> +
> +error_global_free:
> + ttm_mem_global_free_page(&ttm_mem_glob, p, (1 << order) * PAGE_SIZE);
> +
> +error_free_page:
> + ttm_pool_free_page(pool, tt->caching, order, p);
> +
> +error_free_all:
> + num_pages = tt->num_pages - num_pages;
> + for (i = 0; i < num_pages; ) {
> + order = ttm_pool_page_order(pool, tt->pages[i]);
> + ttm_pool_free_page(pool, tt->caching, order, tt->pages[i]);
> + i += 1 << order;
> + }
> +
> + return r;
> +}
> +EXPORT_SYMBOL(ttm_pool_alloc);
> +
> +/**
> + * ttm_pool_free - Free the backing pages from a ttm_tt object
> + *
> + * @pool: Pool to give pages back to.
> + * @tt: ttm_tt object to unpopulate
> + *
> + * Give the packing pages back to a pool or free them
> + */
> +void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < tt->num_pages; ) {
> + struct page *p = tt->pages[i];
> + unsigned int order, num_pages;
> + struct ttm_pool_type *pt;
> +
> + order = ttm_pool_page_order(pool, p);
> + num_pages = 1ULL << order;
> + ttm_mem_global_free_page(&ttm_mem_glob, p,
> + num_pages * PAGE_SIZE);
> + if (tt->dma_address)
> + ttm_pool_unmap(pool, tt->dma_address[i], num_pages);
> +
> + pt = ttm_pool_select_type(pool, tt->caching, order);
> + if (pt)
> + ttm_pool_type_give(pt, tt->pages[i]);
> + else
> + ttm_pool_free_page(pool, tt->caching, order,
> + tt->pages[i]);
> +
> + i += num_pages;
> + }
> +
> + while (atomic_long_read(&allocated_pages) > page_pool_size)
> + ttm_pool_shrink();
> +}
> +EXPORT_SYMBOL(ttm_pool_free);
> +
> +/**
> + * ttm_pool_init - Initialize a pool
> + *
> + * @pool: the pool to initialize
> + * @dev: device for DMA allocations and mappings
> + * @use_dma_alloc: true if coherent DMA alloc should be used
> + * @use_dma32: true if GFP_DMA32 should be used
> + *
> + * Initialize the pool and its pool types.
> + */
> +void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
> + bool use_dma_alloc, bool use_dma32)
> +{
> + unsigned int i, j;
> +
> + WARN_ON(!dev && use_dma_alloc);
> +
> + pool->dev = dev;
> + pool->use_dma_alloc = use_dma_alloc;
> + pool->use_dma32 = use_dma32;
> +
> + for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
> + for (j = 0; j < MAX_ORDER; ++j)
> + ttm_pool_type_init(&pool->caching[i].orders[j],
> + pool, i, j);
> +
> +}
> +EXPORT_SYMBOL(ttm_pool_init);
> +
> +/**
> + * ttm_pool_fini - Cleanup a pool
> + *
> + * @pool: the pool to clean up
> + *
> + * Free all pages in the pool and unregister the types from the global
> + * shrinker.
> + */
> +void ttm_pool_fini(struct ttm_pool *pool)
> +{
> + unsigned int i, j;
> +
> + for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
> + for (j = 0; j < MAX_ORDER; ++j)
> + ttm_pool_type_fini(&pool->caching[i].orders[j]);
> +}
> +EXPORT_SYMBOL(ttm_pool_fini);
> +
> +#ifdef CONFIG_DEBUG_FS
> +
> +/* Dump information about the different pool types */
> +static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
> + struct seq_file *m)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < MAX_ORDER; ++i)
> + seq_printf(m, " %8u", ttm_pool_type_count(&pt[i]));
> + seq_puts(m, "\n");
> +}
> +
> +/**
> + * ttm_pool_debugfs - Debugfs dump function for a pool
> + *
> + * @pool: the pool to dump the information for
> + * @m: seq_file to dump to
> + *
> + * Make a debugfs dump with the per pool and global information.
> + */
> +int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
> +{
> + unsigned int i;
> +
> + spin_lock(&shrinker_lock);
> +
> + seq_puts(m, "\t ");
> + for (i = 0; i < MAX_ORDER; ++i)
> + seq_printf(m, " ---%2u---", i);
> + seq_puts(m, "\n");
> +
> + seq_puts(m, "wc\t:");
> + ttm_pool_debugfs_orders(global_write_combined, m);
> + seq_puts(m, "uc\t:");
> + ttm_pool_debugfs_orders(global_uncached, m);
> +
> + for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) {
> + seq_puts(m, "DMA ");
> + switch (i) {
> + case ttm_cached:
> + seq_puts(m, "\t:");
> + break;
> + case ttm_write_combined:
> + seq_puts(m, "wc\t:");
> + break;
> + case ttm_uncached:
> + seq_puts(m, "uc\t:");
> + break;
> + }
> + ttm_pool_debugfs_orders(pool->caching[i].orders, m);
> + }
> +
> + seq_printf(m, "\ntotal\t: %8lu of %8lu\n",
> + atomic_long_read(&allocated_pages), page_pool_size);
> +
> + spin_unlock(&shrinker_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ttm_pool_debugfs);
> +
> +#endif
> +
> +/* As long as pages are available make sure to release at least one */
> +static unsigned long ttm_pool_shrinker_scan(struct shrinker *shrink,
> + struct shrink_control *sc)
> +{
> + unsigned long num_freed = 0;
> +
> + do
> + num_freed += ttm_pool_shrink();
> + while (!num_freed && atomic_long_read(&allocated_pages));
> +
> + return num_freed;
> +}
> +
> +/* Return the number of pages available or SHRINK_EMPTY if we have none */
> +static unsigned long ttm_pool_shrinker_count(struct shrinker *shrink,
> + struct shrink_control *sc)
> +{
> + unsigned long num_pages = atomic_long_read(&allocated_pages);
> +
> + return num_pages ? num_pages : SHRINK_EMPTY;
> +}
> +
> +/**
> + * ttm_pool_mgr_init - Initialize globals
> + *
> + * @num_pages: default number of pages
> + *
> + * Initialize the global locks and lists for the MM shrinker.
> + */
> +int ttm_pool_mgr_init(unsigned long num_pages)
> +{
> + unsigned int i;
> +
> + if (!page_pool_size)
> + page_pool_size = num_pages;
> +
> + spin_lock_init(&shrinker_lock);
> + INIT_LIST_HEAD(&shrinker_list);
> +
> + for (i = 0; i < MAX_ORDER; ++i) {
> + ttm_pool_type_init(&global_write_combined[i], NULL,
> + ttm_write_combined, i);
> + ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
> + }
> +
> + mm_shrinker.count_objects = ttm_pool_shrinker_count;
> + mm_shrinker.scan_objects = ttm_pool_shrinker_scan;
> + mm_shrinker.seeks = 1;
> + return register_shrinker(&mm_shrinker);
> +}
> +
> +/**
> + * ttm_pool_mgr_fini - Finalize globals
> + *
> + * Cleanup the global pools and unregister the MM shrinker.
> + */
> +void ttm_pool_mgr_fini(void)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < MAX_ORDER; ++i) {
> + ttm_pool_type_fini(&global_write_combined[i]);
> + ttm_pool_type_fini(&global_uncached[i]);
> + }
> +
> + unregister_shrinker(&mm_shrinker);
> + WARN_ON(!list_empty(&shrinker_list));
> +}
> diff --git a/include/drm/ttm/ttm_caching.h b/include/drm/ttm/ttm_caching.h
> index 161624dcf6be..a0b4a49fa432 100644
> --- a/include/drm/ttm/ttm_caching.h
> +++ b/include/drm/ttm/ttm_caching.h
> @@ -25,6 +25,8 @@
> #ifndef _TTM_CACHING_H_
> #define _TTM_CACHING_H_
>
> +#define TTM_NUM_CACHING_TYPES 3
> +
> enum ttm_caching {
> ttm_uncached,
> ttm_write_combined,
> diff --git a/include/drm/ttm/ttm_pool.h b/include/drm/ttm/ttm_pool.h
> new file mode 100644
> index 000000000000..c6bfd8322fe1
> --- /dev/null
> +++ b/include/drm/ttm/ttm_pool.h
> @@ -0,0 +1,90 @@
> +/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> +/*
> + * Copyright 2020 Advanced Micro Devices, 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, sublicense,
> + * 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 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 NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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: Christian König
> + */
> +
> +#ifndef _TTM_PAGE_POOL_H_
> +#define _TTM_PAGE_POOL_H_
> +
> +#include <linux/mmzone.h>
> +#include <linux/llist.h>
> +#include <drm/ttm/ttm_caching.h>
> +
> +struct device;
> +struct ttm_tt;
> +struct ttm_pool;
> +struct ttm_operation_ctx;
> +
> +/**
> + * ttm_pool_type - Pool for a certain memory type
> + *
> + * @pool: the pool we belong to, might be NULL for the global ones
> + * @order: the allocation order our pages have
> + * @caching: the caching type our pages have
> + * @shrinker_list: our place on the global shrinker list
> + * @lock: protection of the page list
> + * @pages: the list of pages in the pool
> + */
> +struct ttm_pool_type {
> + struct ttm_pool *pool;
> + unsigned int order;
> + enum ttm_caching caching;
> +
> + struct list_head shrinker_list;
> +
> + spinlock_t lock;
> + struct list_head pages;
> +};
> +
> +/**
> + * ttm_pool - Pool for all caching and orders
> + *
> + * @use_dma_alloc: if coherent DMA allocations should be used
> + * @use_dma32: if GFP_DMA32 should be used
> + * @caching: pools for each caching/order
> + */
> +struct ttm_pool {
> + struct device *dev;
> +
> + bool use_dma_alloc;
> + bool use_dma32;
> +
> + struct {
> + struct ttm_pool_type orders[MAX_ORDER];
> + } caching[TTM_NUM_CACHING_TYPES];
> +};
> +
> +int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
> + struct ttm_operation_ctx *ctx);
> +void ttm_pool_free(struct ttm_pool *pool, struct ttm_tt *tt);
> +
> +void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
> + bool use_dma_alloc, bool use_dma32);
> +void ttm_pool_fini(struct ttm_pool *pool);
> +
> +int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m);
> +
> +int ttm_pool_mgr_init(unsigned long num_pages);
> +void ttm_pool_mgr_fini(void);
> +
> +#endif
> --
> 2.17.1
>
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