[Intel-gfx] [PATCH 1/1] drm/i915: Replace shmem memory region and object backend with TTM
Matthew Auld
matthew.william.auld at gmail.com
Thu Apr 28 18:04:31 UTC 2022
On Thu, 28 Apr 2022 at 09:39, Adrian Larumbe
<adrian.larumbe at collabora.com> wrote:
>
> Remove shmem region and object backend code as they are now unnecessary.
> In the case of objects placed in SMEM and backed by kernel shmem files, the
> file pointer has to be retrieved from the ttm_tt structure, so change this
> as well. This means accessing an shmem-backed BO's file pointer requires
> getting its pages beforehand, unlike in the old shmem backend.
>
> Expand TTM BO creation by handling devices with no LLC so that their
> caching and coherency properties are set accordingly.
>
> Signed-off-by: Adrian Larumbe <adrian.larumbe at collabora.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 12 +-
> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 32 +-
> drivers/gpu/drm/i915/gem/i915_gem_object.h | 2 +-
> drivers/gpu/drm/i915/gem/i915_gem_phys.c | 5 +-
> drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 397 +------------------
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 212 +++++++++-
> drivers/gpu/drm/i915/gem/i915_gem_ttm.h | 3 +
> drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 11 +-
> drivers/gpu/drm/i915/gt/shmem_utils.c | 64 ++-
> drivers/gpu/drm/i915/intel_memory_region.c | 7 +-
> 10 files changed, 333 insertions(+), 412 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> index f5062d0c6333..de04ce4210b3 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> @@ -12,6 +12,7 @@
> #include <asm/smp.h>
>
> #include "gem/i915_gem_dmabuf.h"
> +#include "gem/i915_gem_ttm.h"
> #include "i915_drv.h"
> #include "i915_gem_object.h"
> #include "i915_scatterlist.h"
> @@ -94,22 +95,25 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *
> {
> struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
> struct drm_i915_private *i915 = to_i915(obj->base.dev);
> + struct file *filp = i915_gem_ttm_get_filep(obj);
> int ret;
>
> + GEM_BUG_ON(obj->base.import_attach != NULL);
> +
> if (obj->base.size < vma->vm_end - vma->vm_start)
> return -EINVAL;
>
> if (HAS_LMEM(i915))
> return drm_gem_prime_mmap(&obj->base, vma);
>
> - if (!obj->base.filp)
> + if (!filp)
> return -ENODEV;
>
> - ret = call_mmap(obj->base.filp, vma);
> + ret = call_mmap(filp, vma);
> if (ret)
> return ret;
>
> - vma_set_file(vma, obj->base.filp);
> + vma_set_file(vma, filp);
>
> return 0;
> }
> @@ -224,6 +228,8 @@ struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags)
> exp_info.priv = gem_obj;
> exp_info.resv = obj->base.resv;
>
> + GEM_BUG_ON(obj->base.import_attach != NULL);
> +
> if (obj->ops->dmabuf_export) {
> int ret = obj->ops->dmabuf_export(obj);
> if (ret)
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> index 0c5c43852e24..d963cf35fdc9 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> @@ -64,7 +64,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> struct drm_i915_private *i915 = to_i915(dev);
> struct drm_i915_gem_mmap *args = data;
> struct drm_i915_gem_object *obj;
> + struct file *filp;
> unsigned long addr;
> + int ret;
>
> /*
> * mmap ioctl is disallowed for all discrete platforms,
> @@ -83,12 +85,20 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> if (!obj)
> return -ENOENT;
>
> - /* prime objects have no backing filp to GEM mmap
> - * pages from.
> - */
> - if (!obj->base.filp) {
> - addr = -ENXIO;
> - goto err;
> + if (obj->base.import_attach)
> + filp = obj->base.filp;
> + else {
> + ret = i915_gem_object_pin_pages_unlocked(obj);
> + if (ret) {
> + addr = ret;
> + goto err_pin;
> + }
> +
> + filp = i915_gem_ttm_get_filep(obj);
> + if (!filp) {
> + addr = -ENXIO;
> + goto err;
> + }
> }
>
> if (range_overflows(args->offset, args->size, (u64)obj->base.size)) {
> @@ -96,7 +106,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> goto err;
> }
>
> - addr = vm_mmap(obj->base.filp, 0, args->size,
> + addr = vm_mmap(filp, 0, args->size,
> PROT_READ | PROT_WRITE, MAP_SHARED,
> args->offset);
> if (IS_ERR_VALUE(addr))
> @@ -111,7 +121,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> goto err;
> }
> vma = find_vma(mm, addr);
> - if (vma && __vma_matches(vma, obj->base.filp, addr, args->size))
> + if (vma && __vma_matches(vma, filp, addr, args->size))
> vma->vm_page_prot =
> pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> else
> @@ -120,12 +130,18 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> if (IS_ERR_VALUE(addr))
> goto err;
> }
> + if (!obj->base.import_attach)
> + i915_gem_object_unpin_pages(obj);
> +
> i915_gem_object_put(obj);
>
> args->addr_ptr = (u64)addr;
> return 0;
>
> err:
> + if (!obj->base.import_attach)
> + i915_gem_object_unpin_pages(obj);
> +err_pin:
> i915_gem_object_put(obj);
> return addr;
> }
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index e11d82a9f7c3..a12f2733075a 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -592,7 +592,7 @@ i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
>
> int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size);
>
> -bool i915_gem_object_is_shmem(const struct drm_i915_gem_object *obj);
> +bool i915_gem_object_is_shmem(struct drm_i915_gem_object *obj);
>
> void __i915_gem_free_object_rcu(struct rcu_head *head);
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
> index 0d0e46dae559..af3c1c43000c 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
> @@ -11,6 +11,7 @@
> #include <drm/drm_cache.h>
>
> #include "gt/intel_gt.h"
> +#include "gem/i915_gem_ttm.h"
> #include "i915_drv.h"
> #include "i915_gem_object.h"
> #include "i915_gem_region.h"
> @@ -19,7 +20,7 @@
>
> static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
> {
> - struct address_space *mapping = obj->base.filp->f_mapping;
> + struct address_space *mapping = i915_gem_ttm_get_filep(obj)->f_mapping;
> struct drm_i915_private *i915 = to_i915(obj->base.dev);
> struct scatterlist *sg;
> struct sg_table *st;
> @@ -28,6 +29,8 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
> void *dst;
> int i;
>
> + GEM_BUG_ON(obj->base.import_attach != NULL);
> +
> if (GEM_WARN_ON(i915_gem_object_needs_bit17_swizzle(obj)))
> return -EINVAL;
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> index c2a3e388fcb4..343eb5897a36 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> @@ -11,12 +11,14 @@
> #include <drm/drm_cache.h>
>
> #include "gem/i915_gem_region.h"
> +#include "gem/i915_gem_ttm.h"
> #include "i915_drv.h"
> #include "i915_gem_object.h"
> #include "i915_gem_tiling.h"
> #include "i915_gemfs.h"
> #include "i915_scatterlist.h"
> #include "i915_trace.h"
> +#include "i915_gem_clflush.h"
>
> /*
> * Move pages to appropriate lru and release the pagevec, decrementing the
> @@ -188,105 +190,6 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st,
> return ret;
> }
>
> -static int shmem_get_pages(struct drm_i915_gem_object *obj)
> -{
> - struct drm_i915_private *i915 = to_i915(obj->base.dev);
> - struct intel_memory_region *mem = obj->mm.region;
> - struct address_space *mapping = obj->base.filp->f_mapping;
> - const unsigned long page_count = obj->base.size / PAGE_SIZE;
> - unsigned int max_segment = i915_sg_segment_size();
> - struct sg_table *st;
> - struct sgt_iter sgt_iter;
> - struct page *page;
> - int ret;
> -
> - /*
> - * Assert that the object is not currently in any GPU domain. As it
> - * wasn't in the GTT, there shouldn't be any way it could have been in
> - * a GPU cache
> - */
> - GEM_BUG_ON(obj->read_domains & I915_GEM_GPU_DOMAINS);
> - GEM_BUG_ON(obj->write_domain & I915_GEM_GPU_DOMAINS);
> -
> -rebuild_st:
> - st = kmalloc(sizeof(*st), GFP_KERNEL);
> - if (!st)
> - return -ENOMEM;
> -
> - ret = shmem_sg_alloc_table(i915, st, obj->base.size, mem, mapping,
> - max_segment);
> - if (ret)
> - goto err_st;
> -
> - ret = i915_gem_gtt_prepare_pages(obj, st);
> - if (ret) {
> - /*
> - * DMA remapping failed? One possible cause is that
> - * it could not reserve enough large entries, asking
> - * for PAGE_SIZE chunks instead may be helpful.
> - */
> - if (max_segment > PAGE_SIZE) {
> - for_each_sgt_page(page, sgt_iter, st)
> - put_page(page);
> - sg_free_table(st);
> - kfree(st);
> -
> - max_segment = PAGE_SIZE;
> - goto rebuild_st;
> - } else {
> - dev_warn(i915->drm.dev,
> - "Failed to DMA remap %lu pages\n",
> - page_count);
> - goto err_pages;
> - }
> - }
> -
> - if (i915_gem_object_needs_bit17_swizzle(obj))
> - i915_gem_object_do_bit_17_swizzle(obj, st);
> -
> - if (i915_gem_object_can_bypass_llc(obj))
> - obj->cache_dirty = true;
> -
> - __i915_gem_object_set_pages(obj, st, i915_sg_dma_sizes(st->sgl));
> -
> - return 0;
> -
> -err_pages:
> - shmem_sg_free_table(st, mapping, false, false);
> - /*
> - * shmemfs first checks if there is enough memory to allocate the page
> - * and reports ENOSPC should there be insufficient, along with the usual
> - * ENOMEM for a genuine allocation failure.
> - *
> - * We use ENOSPC in our driver to mean that we have run out of aperture
> - * space and so want to translate the error from shmemfs back to our
> - * usual understanding of ENOMEM.
> - */
> -err_st:
> - if (ret == -ENOSPC)
> - ret = -ENOMEM;
> -
> - kfree(st);
> -
> - return ret;
> -}
> -
> -static int
> -shmem_truncate(struct drm_i915_gem_object *obj)
> -{
> - /*
> - * Our goal here is to return as much of the memory as
> - * is possible back to the system as we are called from OOM.
> - * To do this we must instruct the shmfs to drop all of its
> - * backing pages, *now*.
> - */
> - shmem_truncate_range(file_inode(obj->base.filp), 0, (loff_t)-1);
> - obj->mm.madv = __I915_MADV_PURGED;
> - obj->mm.pages = ERR_PTR(-EFAULT);
> -
> - return 0;
> -}
> -
> void __shmem_writeback(size_t size, struct address_space *mapping)
> {
> struct writeback_control wbc = {
> @@ -329,27 +232,6 @@ void __shmem_writeback(size_t size, struct address_space *mapping)
> }
> }
>
> -static void
> -shmem_writeback(struct drm_i915_gem_object *obj)
> -{
> - __shmem_writeback(obj->base.size, obj->base.filp->f_mapping);
> -}
> -
> -static int shmem_shrink(struct drm_i915_gem_object *obj, unsigned int flags)
> -{
> - switch (obj->mm.madv) {
> - case I915_MADV_DONTNEED:
> - return i915_gem_object_truncate(obj);
> - case __I915_MADV_PURGED:
> - return 0;
> - }
> -
> - if (flags & I915_GEM_OBJECT_SHRINK_WRITEBACK)
> - shmem_writeback(obj);
> -
> - return 0;
> -}
> -
> void
> __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
> struct sg_table *pages,
> @@ -395,220 +277,6 @@ void i915_gem_object_put_pages_shmem(struct drm_i915_gem_object *obj, struct sg_
> obj->mm.dirty = false;
> }
>
> -static void
> -shmem_put_pages(struct drm_i915_gem_object *obj, struct sg_table *pages)
> -{
> - if (likely(i915_gem_object_has_struct_page(obj)))
> - i915_gem_object_put_pages_shmem(obj, pages);
> - else
> - i915_gem_object_put_pages_phys(obj, pages);
> -}
> -
> -static int
> -shmem_pwrite(struct drm_i915_gem_object *obj,
> - const struct drm_i915_gem_pwrite *arg)
> -{
> - struct address_space *mapping = obj->base.filp->f_mapping;
> - char __user *user_data = u64_to_user_ptr(arg->data_ptr);
> - u64 remain, offset;
> - unsigned int pg;
> -
> - /* Caller already validated user args */
> - GEM_BUG_ON(!access_ok(user_data, arg->size));
> -
> - if (!i915_gem_object_has_struct_page(obj))
> - return i915_gem_object_pwrite_phys(obj, arg);
> -
> - /*
> - * Before we instantiate/pin the backing store for our use, we
> - * can prepopulate the shmemfs filp efficiently using a write into
> - * the pagecache. We avoid the penalty of instantiating all the
> - * pages, important if the user is just writing to a few and never
> - * uses the object on the GPU, and using a direct write into shmemfs
> - * allows it to avoid the cost of retrieving a page (either swapin
> - * or clearing-before-use) before it is overwritten.
> - */
> - if (i915_gem_object_has_pages(obj))
> - return -ENODEV;
> -
> - if (obj->mm.madv != I915_MADV_WILLNEED)
> - return -EFAULT;
> -
> - /*
> - * Before the pages are instantiated the object is treated as being
> - * in the CPU domain. The pages will be clflushed as required before
> - * use, and we can freely write into the pages directly. If userspace
> - * races pwrite with any other operation; corruption will ensue -
> - * that is userspace's prerogative!
> - */
> -
> - remain = arg->size;
> - offset = arg->offset;
> - pg = offset_in_page(offset);
> -
> - do {
> - unsigned int len, unwritten;
> - struct page *page;
> - void *data, *vaddr;
> - int err;
> - char c;
> -
> - len = PAGE_SIZE - pg;
> - if (len > remain)
> - len = remain;
> -
> - /* Prefault the user page to reduce potential recursion */
> - err = __get_user(c, user_data);
> - if (err)
> - return err;
> -
> - err = __get_user(c, user_data + len - 1);
> - if (err)
> - return err;
> -
> - err = pagecache_write_begin(obj->base.filp, mapping,
> - offset, len, 0,
> - &page, &data);
> - if (err < 0)
> - return err;
> -
> - vaddr = kmap_atomic(page);
> - unwritten = __copy_from_user_inatomic(vaddr + pg,
> - user_data,
> - len);
> - kunmap_atomic(vaddr);
> -
> - err = pagecache_write_end(obj->base.filp, mapping,
> - offset, len, len - unwritten,
> - page, data);
> - if (err < 0)
> - return err;
> -
> - /* We don't handle -EFAULT, leave it to the caller to check */
> - if (unwritten)
> - return -ENODEV;
> -
> - remain -= len;
> - user_data += len;
> - offset += len;
> - pg = 0;
> - } while (remain);
> -
> - return 0;
> -}
> -
> -static int
> -shmem_pread(struct drm_i915_gem_object *obj,
> - const struct drm_i915_gem_pread *arg)
> -{
> - if (!i915_gem_object_has_struct_page(obj))
> - return i915_gem_object_pread_phys(obj, arg);
> -
> - return -ENODEV;
> -}
> -
> -static void shmem_release(struct drm_i915_gem_object *obj)
> -{
> - if (i915_gem_object_has_struct_page(obj))
> - i915_gem_object_release_memory_region(obj);
> -
> - fput(obj->base.filp);
> -}
> -
> -const struct drm_i915_gem_object_ops i915_gem_shmem_ops = {
> - .name = "i915_gem_object_shmem",
> - .flags = I915_GEM_OBJECT_IS_SHRINKABLE,
> -
> - .get_pages = shmem_get_pages,
> - .put_pages = shmem_put_pages,
> - .truncate = shmem_truncate,
> - .shrink = shmem_shrink,
> -
> - .pwrite = shmem_pwrite,
> - .pread = shmem_pread,
> -
> - .release = shmem_release,
> -};
> -
> -static int __create_shmem(struct drm_i915_private *i915,
> - struct drm_gem_object *obj,
> - resource_size_t size)
> -{
> - unsigned long flags = VM_NORESERVE;
> - struct file *filp;
> -
> - drm_gem_private_object_init(&i915->drm, obj, size);
> -
> - if (i915->mm.gemfs)
> - filp = shmem_file_setup_with_mnt(i915->mm.gemfs, "i915", size,
> - flags);
> - else
> - filp = shmem_file_setup("i915", size, flags);
> - if (IS_ERR(filp))
> - return PTR_ERR(filp);
> -
> - obj->filp = filp;
> - return 0;
> -}
> -
> -static int shmem_object_init(struct intel_memory_region *mem,
> - struct drm_i915_gem_object *obj,
> - resource_size_t offset,
> - resource_size_t size,
> - resource_size_t page_size,
> - unsigned int flags)
> -{
> - static struct lock_class_key lock_class;
> - struct drm_i915_private *i915 = mem->i915;
> - struct address_space *mapping;
> - unsigned int cache_level;
> - gfp_t mask;
> - int ret;
> -
> - ret = __create_shmem(i915, &obj->base, size);
> - if (ret)
> - return ret;
> -
> - mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
> - if (IS_I965GM(i915) || IS_I965G(i915)) {
> - /* 965gm cannot relocate objects above 4GiB. */
> - mask &= ~__GFP_HIGHMEM;
> - mask |= __GFP_DMA32;
> - }
> -
> - mapping = obj->base.filp->f_mapping;
> - mapping_set_gfp_mask(mapping, mask);
> - GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM));
> -
> - i915_gem_object_init(obj, &i915_gem_shmem_ops, &lock_class, 0);
> - obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
> - obj->write_domain = I915_GEM_DOMAIN_CPU;
> - obj->read_domains = I915_GEM_DOMAIN_CPU;
> -
> - if (HAS_LLC(i915))
> - /* On some devices, we can have the GPU use the LLC (the CPU
> - * cache) for about a 10% performance improvement
> - * compared to uncached. Graphics requests other than
> - * display scanout are coherent with the CPU in
> - * accessing this cache. This means in this mode we
> - * don't need to clflush on the CPU side, and on the
> - * GPU side we only need to flush internal caches to
> - * get data visible to the CPU.
> - *
> - * However, we maintain the display planes as UC, and so
> - * need to rebind when first used as such.
> - */
> - cache_level = I915_CACHE_LLC;
> - else
> - cache_level = I915_CACHE_NONE;
> -
> - i915_gem_object_set_cache_coherency(obj, cache_level);
> -
> - i915_gem_object_init_memory_region(obj, mem);
> -
> - return 0;
> -}
> -
> struct drm_i915_gem_object *
> i915_gem_object_create_shmem(struct drm_i915_private *i915,
> resource_size_t size)
> @@ -634,7 +302,19 @@ i915_gem_object_create_shmem_from_data(struct drm_i915_private *dev_priv,
>
> GEM_BUG_ON(obj->write_domain != I915_GEM_DOMAIN_CPU);
>
> - file = obj->base.filp;
> + /*
> + * When using TTM as the main GEM backend, we need to pin the pages
> + * after creating the object to access the file pointer
> + */
> + err = i915_gem_object_pin_pages_unlocked(obj);
> + if (err) {
> + drm_dbg(&dev_priv->drm, "%s pin-pages err=%d\n", __func__, err);
> + goto fail_pin;
> + }
> +
> + file = i915_gem_ttm_get_filep(obj);
> + GEM_WARN_ON(file == NULL);
> +
> offset = 0;
> do {
> unsigned int len = min_t(typeof(size), size, PAGE_SIZE);
> @@ -662,51 +342,14 @@ i915_gem_object_create_shmem_from_data(struct drm_i915_private *dev_priv,
> offset += len;
> } while (size);
>
> + i915_gem_clflush_object(obj, I915_CLFLUSH_SYNC);
> + i915_gem_object_unpin_pages(obj);
> +
> return obj;
>
> fail:
> + i915_gem_object_unpin_pages(obj);
> +fail_pin:
> i915_gem_object_put(obj);
> return ERR_PTR(err);
> }
> -
> -static int init_shmem(struct intel_memory_region *mem)
> -{
> - int err;
> -
> - err = i915_gemfs_init(mem->i915);
> - if (err) {
> - DRM_NOTE("Unable to create a private tmpfs mount, hugepage support will be disabled(%d).\n",
> - err);
> - }
> -
> - intel_memory_region_set_name(mem, "system");
> -
> - return 0; /* Don't error, we can simply fallback to the kernel mnt */
> -}
> -
> -static int release_shmem(struct intel_memory_region *mem)
> -{
> - i915_gemfs_fini(mem->i915);
> - return 0;
> -}
> -
> -static const struct intel_memory_region_ops shmem_region_ops = {
> - .init = init_shmem,
> - .release = release_shmem,
> - .init_object = shmem_object_init,
> -};
> -
> -struct intel_memory_region *i915_gem_shmem_setup(struct drm_i915_private *i915,
> - u16 type, u16 instance)
> -{
> - return intel_memory_region_create(i915, 0,
> - totalram_pages() << PAGE_SHIFT,
> - PAGE_SIZE, 0, 0,
> - type, instance,
> - &shmem_region_ops);
> -}
> -
> -bool i915_gem_object_is_shmem(const struct drm_i915_gem_object *obj)
> -{
> - return obj->ops == &i915_gem_shmem_ops;
> -}
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 4c25d9b2f138..e4f3a467abd8 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -21,6 +21,7 @@
> #include "gem/i915_gem_ttm_move.h"
> #include "gem/i915_gem_ttm_pm.h"
> #include "gt/intel_gpu_commands.h"
> +#include "gem/i915_gem_tiling.h"
>
> #define I915_TTM_PRIO_PURGE 0
> #define I915_TTM_PRIO_NO_PAGES 1
> @@ -37,6 +38,7 @@
> * @ttm: The base TTM page vector.
> * @dev: The struct device used for dma mapping and unmapping.
> * @cached_rsgt: The cached scatter-gather table.
> + * @bo: TTM buffer object this ttm_tt structure is bound to.
> * @is_shmem: Set if using shmem.
> * @filp: The shmem file, if using shmem backend.
> *
> @@ -50,6 +52,7 @@ struct i915_ttm_tt {
> struct ttm_tt ttm;
> struct device *dev;
> struct i915_refct_sgt cached_rsgt;
> + struct ttm_buffer_object *bo;
>
> bool is_shmem;
> struct file *filp;
> @@ -113,6 +116,10 @@ static int i915_ttm_err_to_gem(int err)
> static enum ttm_caching
> i915_ttm_select_tt_caching(const struct drm_i915_gem_object *obj)
> {
> + struct drm_i915_private *i915 = to_i915(obj->base.dev);
> +
> + if (GRAPHICS_VER(i915) <= 5)
> + return ttm_uncached;
> /*
> * Objects only allowed in system get cached cpu-mappings, or when
> * evicting lmem-only buffers to system for swapping. Other objects get
> @@ -207,6 +214,11 @@ static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev,
> return PTR_ERR(filp);
>
> mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
> + if (IS_I965GM(i915) || IS_I965G(i915)) {
> + /* 965gm cannot relocate objects above 4GiB. */
> + mask &= ~__GFP_HIGHMEM;
> + mask |= __GFP_DMA32;
> + }
>
> mapping = filp->f_mapping;
> mapping_set_gfp_mask(mapping, mask);
> @@ -304,12 +316,14 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
> if (!i915_tt)
> return NULL;
>
> + i915_tt->bo = bo;
> +
> if (obj->flags & I915_BO_ALLOC_CPU_CLEAR &&
> man->use_tt)
> page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
>
> caching = i915_ttm_select_tt_caching(obj);
> - if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached) {
> + if (i915_gem_object_is_shrinkable(obj) && (caching != ttm_write_combined)) {
> page_flags |= TTM_TT_FLAG_EXTERNAL |
> TTM_TT_FLAG_EXTERNAL_MAPPABLE;
> i915_tt->is_shmem = true;
> @@ -352,11 +366,19 @@ static void i915_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
> {
> struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
> struct sg_table *st = &i915_tt->cached_rsgt.table;
> + struct ttm_buffer_object *bo = i915_tt->bo;
> + struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> +
> + if (i915_tt->is_shmem)
> + __i915_gem_object_release_shmem(obj, st, true);
>
> if (st->sgl)
> dma_unmap_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0);
>
> if (i915_tt->is_shmem) {
> + if (i915_gem_object_needs_bit17_swizzle(obj))
> + i915_gem_object_save_bit_17_swizzle(obj, st);
> +
> i915_ttm_tt_shmem_unpopulate(ttm);
> } else {
> sg_free_table(st);
> @@ -798,6 +820,12 @@ static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
> obj->mm.rsgt = rsgt;
> __i915_gem_object_set_pages(obj, &rsgt->table,
> i915_sg_dma_sizes(rsgt->table.sgl));
> +
> + if (i915_gem_object_needs_bit17_swizzle(obj))
> + i915_gem_object_save_bit_17_swizzle(obj, &rsgt->table);
> +
> + if (i915_gem_object_can_bypass_llc(obj))
> + obj->cache_dirty = true;
This needs to happen before the set_pages(), otherwise we are skipping
the flush-on-acquire.
> }
>
> GEM_BUG_ON(bo->ttm && ((obj->base.size >> PAGE_SHIFT) < bo->ttm->num_pages));
> @@ -979,6 +1007,119 @@ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
> spin_unlock(&bo->bdev->lru_lock);
> }
>
> +static int
> +i915_ttm_pwrite(struct drm_i915_gem_object *obj,
> + const struct drm_i915_gem_pwrite *arg)
> +{
> + struct drm_i915_private *i915 = to_i915(obj->base.dev);
> + char __user *user_data = u64_to_user_ptr(arg->data_ptr);
> + struct address_space *mapping;
> + u64 remain, offset;
> + struct file *filp;
> + unsigned int pg;
> + int err;
> +
> + /* Caller already validated user args */
> + GEM_BUG_ON(!access_ok(user_data, arg->size));
> +
> + if (!i915_gem_object_has_struct_page(obj))
> + return i915_gem_object_pwrite_phys(obj, arg);
> +
> + /*
> + * We need to pin the pages in order to have access to the filp
> + * given by shmem, quite unlike in the legacy GEM shmem backend
> + * where it would be available upon object creation
> + */
> + err = i915_gem_object_pin_pages_unlocked(obj);
> + if (err) {
> + drm_dbg(&i915->drm, "%s pin-pages err=%d\n", __func__, err);
> + return err;
> + }
> +
> + filp = i915_gem_ttm_get_filep(obj);
> + if (!filp) {
> + err = -ENXIO;
> + goto error;
> + }
> +
> + mapping = filp->f_mapping;
> +
> + if (obj->mm.madv != I915_MADV_WILLNEED) {
> + err = -EFAULT;
> + goto error;
> + }
> +
> + /*
> + * Before the pages are instantiated the object is treated as being
> + * in the CPU domain. The pages will be clflushed as required before
> + * use, and we can freely write into the pages directly. If userspace
> + * races pwrite with any other operation; corruption will ensue -
> + * that is userspace's prerogative!
> + */
> +
> + remain = arg->size;
> + offset = arg->offset;
> + pg = offset_in_page(offset);
> +
> + do {
> + unsigned int len, unwritten;
> + struct page *page;
> + void *data, *vaddr;
> + int err;
> + char c;
> +
> + len = PAGE_SIZE - pg;
> + if (len > remain)
> + len = remain;
> +
> + /* Prefault the user page to reduce potential recursion */
> + err = __get_user(c, user_data);
> + if (err)
> + goto error;
> +
> + err = __get_user(c, user_data + len - 1);
> + if (err)
> + goto error;
> +
> + err = pagecache_write_begin(obj->base.filp, mapping,
> + offset, len, 0,
> + &page, &data);
> + if (err < 0)
> + goto error;
> +
> + vaddr = kmap_atomic(page);
> + unwritten = __copy_from_user_inatomic(vaddr + pg,
> + user_data,
> + len);
> + kunmap_atomic(vaddr);
> +
> + err = pagecache_write_end(obj->base.filp, mapping,
> + offset, len, len - unwritten,
> + page, data);
> + if (err < 0)
> + goto error;
> +
> + /* We don't handle -EFAULT, leave it to the caller to check */
> + if (unwritten) {
> + err = -ENODEV;
> + goto error;
> + }
> +
> + remain -= len;
> + user_data += len;
> + offset += len;
> + pg = 0;
> + } while (remain);
> +
> + i915_gem_object_unpin_pages(obj);
> +
> + return 0;
> +
> +error:
> + i915_gem_object_unpin_pages(obj);
> + return err;
> +}
> +
> /*
> * TTM-backed gem object destruction requires some clarification.
> * Basically we have two possibilities here. We can either rely on the
> @@ -1120,7 +1261,7 @@ static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj)
> ttm_bo_unmap_virtual(i915_gem_to_ttm(obj));
> }
>
> -static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
> +static const struct drm_i915_gem_object_ops i915_gem_ttm_discrete_ops = {
> .name = "i915_gem_object_ttm",
> .flags = I915_GEM_OBJECT_IS_SHRINKABLE |
> I915_GEM_OBJECT_SELF_MANAGED_SHRINK_LIST,
> @@ -1139,6 +1280,22 @@ static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
> .mmap_ops = &vm_ops_ttm,
> };
>
> +static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_integrated_ops = {
> + .name = "i915_gem_object_ttm",
> + .flags = I915_GEM_OBJECT_IS_SHRINKABLE |
> + I915_GEM_OBJECT_SELF_MANAGED_SHRINK_LIST,
> +
> + .get_pages = i915_ttm_get_pages,
> + .put_pages = i915_ttm_put_pages,
> + .truncate = i915_ttm_truncate,
> + .shrink = i915_ttm_shrink,
> +
> + .pwrite = i915_ttm_pwrite,
> +
> + .adjust_lru = i915_ttm_adjust_lru,
> + .delayed_free = i915_ttm_delayed_free,
> +};
> +
> void i915_ttm_bo_destroy(struct ttm_buffer_object *bo)
> {
> struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> @@ -1196,7 +1353,12 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
> int ret;
>
> drm_gem_private_object_init(&i915->drm, &obj->base, size);
> - i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags);
> +
> + if (IS_DGFX(i915))
> + i915_gem_object_init(obj, &i915_gem_ttm_discrete_ops, &lock_class, flags);
> + else
> + i915_gem_object_init(obj, &i915_gem_ttm_obj_integrated_ops, &lock_class,
> + flags);
>
> obj->bo_offset = offset;
>
> @@ -1206,8 +1368,8 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
>
> INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL | __GFP_NOWARN);
> mutex_init(&obj->ttm.get_io_page.lock);
> - bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device :
> - ttm_bo_type_kernel;
> + bo_type = (obj->ops->mmap_offset && (obj->flags & I915_BO_ALLOC_USER)) ?
> + ttm_bo_type_device : ttm_bo_type_kernel;
>
> obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);
>
> @@ -1251,6 +1413,27 @@ static const struct intel_memory_region_ops ttm_system_region_ops = {
> .release = intel_region_ttm_fini,
> };
>
> +/**
> + * Return: filp.
> + */
> +struct file *
> +i915_gem_ttm_get_filep(struct drm_i915_gem_object *obj)
> +{
> + struct drm_device *dev = obj->base.dev;
> + struct ttm_buffer_object *bo;
> + struct i915_ttm_tt *i915_tt;
> +
> + bo = i915_gem_to_ttm(obj);
> + if (!bo->ttm) {
> + drm_dbg(dev, "ttm has not been allocated for bo\n");
> + return NULL;
> + }
> +
> + i915_tt = container_of(bo->ttm, typeof(*i915_tt), ttm);
> +
> + return i915_tt->filp;
> +}
> +
> struct intel_memory_region *
> i915_gem_ttm_system_setup(struct drm_i915_private *i915,
> u16 type, u16 instance)
> @@ -1268,3 +1451,22 @@ i915_gem_ttm_system_setup(struct drm_i915_private *i915,
> intel_memory_region_set_name(mr, "system-ttm");
> return mr;
> }
> +
> +bool i915_gem_object_is_shmem(struct drm_i915_gem_object *obj)
> +{
> + struct intel_memory_region *mr = READ_ONCE(obj->mm.region);
> +
> +#ifdef CONFIG_LOCKDEP
> + if (i915_gem_object_migratable(obj) &&
> + i915_gem_object_evictable(obj))
> + assert_object_held(obj);
> +#endif
> +
> + /* Review list of placements to make sure object isn't migratable */
> + if (i915_gem_object_placement_possible(obj, INTEL_MEMORY_LOCAL))
> + return false;
> +
> + return mr && (mr->type == INTEL_MEMORY_SYSTEM &&
> + (obj->ops == &i915_gem_ttm_obj_integrated_ops ||
> + obj->ops == &i915_gem_ttm_discrete_ops));
> +}
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
> index 73e371aa3850..f00f18db5a8b 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.h
> @@ -92,4 +92,7 @@ static inline bool i915_ttm_cpu_maps_iomem(struct ttm_resource *mem)
> /* Once / if we support GGTT, this is also false for cached ttm_tts */
> return mem->mem_type != I915_PL_SYSTEM;
> }
> +
> +struct file *i915_gem_ttm_get_filep(struct drm_i915_gem_object *obj);
> +
> #endif
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> index a10716f4e717..c588e31aa479 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> @@ -46,6 +46,10 @@ static enum i915_cache_level
> i915_ttm_cache_level(struct drm_i915_private *i915, struct ttm_resource *res,
> struct ttm_tt *ttm)
> {
> +
> + if (GRAPHICS_VER(i915) <= 5)
> + return I915_CACHE_NONE;
IIUC we are no longer using CACHE_NONE by default on snooping
platforms gen > 5? That's a pretty big change, AFAIK there are power
and perf considerations when enabling CACHE_LLC/L3 on snooping
platforms, which is why it was disabled by default.
We also need to be careful to ensure we always set cache_dirty = true,
before first populating the pages on all HAS_SNOOP()
platforms(ignoring discrete) to ensure we always do the
flush-on-acquire. The CACHE_NONE thing was basically ensuring that
previously.
Can we keep the previous default behaviour with using CACHE_NONE on
all platforms that don't have HAS_LLC(), where it is not also
discrete?
We also need to ensure we never trample the cache_level etc for the
object after creation, since userspace(and some in-kernel users) needs
to be to able control it.
> +
> return ((HAS_LLC(i915) || HAS_SNOOP(i915)) &&
> !i915_ttm_gtt_binds_lmem(res) &&
> ttm->caching == ttm_cached) ? I915_CACHE_LLC :
> @@ -77,7 +81,12 @@ void i915_ttm_adjust_domains_after_move(struct drm_i915_gem_object *obj)
> {
> struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
>
> - if (i915_ttm_cpu_maps_iomem(bo->resource) || bo->ttm->caching != ttm_cached) {
> + if (!i915_ttm_cpu_maps_iomem(bo->resource) &&
> + bo->ttm->caching == ttm_uncached) {
> + obj->write_domain = I915_GEM_DOMAIN_CPU;
> + obj->read_domains = I915_GEM_DOMAIN_CPU;
> + } else if (i915_ttm_cpu_maps_iomem(bo->resource) ||
> + bo->ttm->caching != ttm_cached) {
> obj->write_domain = I915_GEM_DOMAIN_WC;
> obj->read_domains = I915_GEM_DOMAIN_WC;
> } else {
> diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c b/drivers/gpu/drm/i915/gt/shmem_utils.c
> index 402f085f3a02..4f842094e484 100644
> --- a/drivers/gpu/drm/i915/gt/shmem_utils.c
> +++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
> @@ -10,6 +10,9 @@
>
> #include "gem/i915_gem_object.h"
> #include "gem/i915_gem_lmem.h"
> +#include "gem/i915_gem_ttm.h"
> +
> +#include "i915_drv.h"
> #include "shmem_utils.h"
>
> struct file *shmem_create_from_data(const char *name, void *data, size_t len)
> @@ -30,24 +33,65 @@ struct file *shmem_create_from_data(const char *name, void *data, size_t len)
> return file;
> }
>
> +static int shmem_flush_object(struct file *file, unsigned long num_pages)
> +{
> + struct page *page;
> + unsigned long pfn;
> +
> + for (pfn = 0; pfn < num_pages; pfn++) {
> + page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
> + GFP_KERNEL);
> + if (IS_ERR(page))
> + return PTR_ERR(page);
> +
> + set_page_dirty(page);
> + mark_page_accessed(page);
> + kunmap(page);
> + put_page(page);
> + }
> +
> + return 0;
> +}
> +
> struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
> {
> + struct drm_i915_private *i915 = to_i915(obj->base.dev);
> struct file *file;
> void *ptr;
> + int err;
>
> if (i915_gem_object_is_shmem(obj)) {
> - file = obj->base.filp;
> - atomic_long_inc(&file->f_count);
> - return file;
> - }
>
> - ptr = i915_gem_object_pin_map_unlocked(obj, i915_gem_object_is_lmem(obj) ?
> - I915_MAP_WC : I915_MAP_WB);
> - if (IS_ERR(ptr))
> - return ERR_CAST(ptr);
> + GEM_BUG_ON(!i915_gem_object_has_pages(obj));
>
> - file = shmem_create_from_data("", ptr, obj->base.size);
> - i915_gem_object_unpin_map(obj);
> + err = i915_gem_object_pin_pages_unlocked(obj);
> + if (err) {
> + drm_dbg(&i915->drm, "%s pin-pages err=%d\n", __func__,
> + err);
> + return ERR_PTR(err);
> + }
> +
> + file = i915_gem_ttm_get_filep(obj);
> + GEM_BUG_ON(!file);
> +
> + err = shmem_flush_object(file, obj->base.size >> PAGE_SHIFT);
> + if (err) {
> + drm_dbg(&i915->drm, "shmem_flush_object failed\n");
> + i915_gem_object_unpin_pages(obj);
> + return ERR_PTR(err);
> + }
> +
> + atomic_long_inc(&file->f_count);
> + i915_gem_object_unpin_pages(obj);
> + } else {
> + ptr = i915_gem_object_pin_map_unlocked(obj, i915_gem_object_is_lmem(obj) ?
> + I915_MAP_WC : I915_MAP_WB);
> + if (IS_ERR(ptr))
> + return ERR_CAST(ptr);
> +
> + file = shmem_create_from_data("", ptr, obj->base.size);
> + i915_gem_object_unpin_map(obj);
> + }
>
> return file;
> }
> diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
> index e38d2db1c3e3..82b6684d7e60 100644
> --- a/drivers/gpu/drm/i915/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/intel_memory_region.c
> @@ -309,12 +309,7 @@ int intel_memory_regions_hw_probe(struct drm_i915_private *i915)
> instance = intel_region_map[i].instance;
> switch (type) {
> case INTEL_MEMORY_SYSTEM:
> - if (IS_DGFX(i915))
> - mem = i915_gem_ttm_system_setup(i915, type,
> - instance);
> - else
> - mem = i915_gem_shmem_setup(i915, type,
> - instance);
> + mem = i915_gem_ttm_system_setup(i915, type, instance);
> break;
> case INTEL_MEMORY_STOLEN_LOCAL:
> mem = i915_gem_stolen_lmem_setup(i915, type, instance);
> --
> 2.35.1
>
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