This patch attempts to fix up shortcomings with the current calling sequences.

1) There's a fastpath where no locking occurs and only io_mem_reserved is called to obtain needed info for mapping. The fastpath is set per memory type manager. 2) If the fastpath is disabled, io_mem_reserve and io_mem_free will be exactly balanced and not called recursively for the same struct ttm_mem_reg. 3) Optionally the driver can choose to enable a per memory type manager LRU eviction mechanism that, when io_mem_reserve returns -EAGAIN will attempt to kill user-space mappings of memory in that manager to free up needed resources

Signed-off-by: Thomas Hellstrom thellstrom@vmware.com --- drivers/gpu/drm/ttm/ttm_bo.c | 44 ++++++++++-- drivers/gpu/drm/ttm/ttm_bo_util.c | 129 +++++++++++++++++++++++++++++++++---- drivers/gpu/drm/ttm/ttm_bo_vm.c | 23 ++++-- include/drm/ttm/ttm_bo_api.h | 6 ++- include/drm/ttm/ttm_bo_driver.h | 104 ++++++++++++++++-------------- 5 files changed, 226 insertions(+), 80 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 336a39d..489bde8 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -361,8 +361,13 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo, int ret = 0;

if (old_is_pci || new_is_pci || - ((mem->placement & bo->mem.placement & TTM_PL_MASK_CACHING) == 0)) - ttm_bo_unmap_virtual(bo); + ((mem->placement & bo->mem.placement & TTM_PL_MASK_CACHING) == 0)) { + ret = ttm_mem_io_lock(old_man, true); + if (unlikely(ret != 0)) + goto out_err; + ttm_bo_unmap_virtual_locked(bo); + ttm_mem_io_unlock(old_man); + }

/* * Create and bind a ttm if required. @@ -451,7 +456,6 @@ static void ttm_bo_cleanup_memtype_use(struct ttm_buffer_object *bo) ttm_tt_destroy(bo->ttm); bo->ttm = NULL; } - ttm_bo_mem_put(bo, &bo->mem);

atomic_set(&bo->reserved, 0); @@ -651,6 +655,7 @@ static void ttm_bo_release(struct kref *kref) struct ttm_buffer_object *bo = container_of(kref, struct ttm_buffer_object, kref); struct ttm_bo_device *bdev = bo->bdev; + struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type];

if (likely(bo->vm_node != NULL)) { rb_erase(&bo->vm_rb, &bdev->addr_space_rb); @@ -658,6 +663,9 @@ static void ttm_bo_release(struct kref *kref) bo->vm_node = NULL; } write_unlock(&bdev->vm_lock); + ttm_mem_io_lock(man, false); + ttm_mem_io_free_vm(bo); + ttm_mem_io_unlock(man); ttm_bo_cleanup_refs_or_queue(bo); kref_put(&bo->list_kref, ttm_bo_release_list); write_lock(&bdev->vm_lock); @@ -714,7 +722,8 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible,

evict_mem = bo->mem; evict_mem.mm_node = NULL; - evict_mem.bus.io_reserved = false; + evict_mem.bus.io_reserved_vm = false; + evict_mem.bus.io_reserved_count = 0;

placement.fpfn = 0; placement.lpfn = 0; @@ -1051,7 +1060,8 @@ int ttm_bo_move_buffer(struct ttm_buffer_object *bo, mem.num_pages = bo->num_pages; mem.size = mem.num_pages << PAGE_SHIFT; mem.page_alignment = bo->mem.page_alignment; - mem.bus.io_reserved = false; + mem.bus.io_reserved_vm = false; + mem.bus.io_reserved_count = 0; /* * Determine where to move the buffer. */ @@ -1171,6 +1181,7 @@ int ttm_bo_init(struct ttm_bo_device *bdev, INIT_LIST_HEAD(&bo->lru); INIT_LIST_HEAD(&bo->ddestroy); INIT_LIST_HEAD(&bo->swap); + INIT_LIST_HEAD(&bo->io_reserve_lru); bo->bdev = bdev; bo->glob = bdev->glob; bo->type = type; @@ -1180,7 +1191,8 @@ int ttm_bo_init(struct ttm_bo_device *bdev, bo->mem.num_pages = bo->num_pages; bo->mem.mm_node = NULL; bo->mem.page_alignment = page_alignment; - bo->mem.bus.io_reserved = false; + bo->mem.bus.io_reserved_vm = false; + bo->mem.bus.io_reserved_count = 0; bo->buffer_start = buffer_start & PAGE_MASK; bo->priv_flags = 0; bo->mem.placement = (TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED); @@ -1354,6 +1366,10 @@ int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type, BUG_ON(type >= TTM_NUM_MEM_TYPES); man = &bdev->man[type]; BUG_ON(man->has_type); + man->io_reserve_fastpath = true; + man->use_io_reserve_lru = false; + mutex_init(&man->io_reserve_mutex); + INIT_LIST_HEAD(&man->io_reserve_lru);

ret = bdev->driver->init_mem_type(bdev, type, man); if (ret) @@ -1560,7 +1576,7 @@ bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem) return true; }

-void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo) +void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo) { struct ttm_bo_device *bdev = bo->bdev; loff_t offset = (loff_t) bo->addr_space_offset; @@ -1569,8 +1585,20 @@ void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo) if (!bdev->dev_mapping) return; unmap_mapping_range(bdev->dev_mapping, offset, holelen, 1); - ttm_mem_io_free(bdev, &bo->mem); + ttm_mem_io_free_vm(bo); } + +void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo) +{ + struct ttm_bo_device *bdev = bo->bdev; + struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type]; + + ttm_mem_io_lock(man, false); + ttm_bo_unmap_virtual_locked(bo); + ttm_mem_io_unlock(man); +} + + EXPORT_SYMBOL(ttm_bo_unmap_virtual);

static void ttm_bo_vm_insert_rb(struct ttm_buffer_object *bo) diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 3106d5b..ae82e54 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -75,37 +75,123 @@ int ttm_bo_move_ttm(struct ttm_buffer_object *bo, } EXPORT_SYMBOL(ttm_bo_move_ttm);

-int ttm_mem_io_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem) +int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible) { - int ret; + if (likely(man->io_reserve_fastpath)) + return 0; + + if (interruptible) + return mutex_lock_interruptible(&man->io_reserve_mutex); + + mutex_lock(&man->io_reserve_mutex); + return 0; +}

- if (!mem->bus.io_reserved) { - mem->bus.io_reserved = true; +void ttm_mem_io_unlock(struct ttm_mem_type_manager *man) +{ + if (likely(man->io_reserve_fastpath)) + return; + + mutex_unlock(&man->io_reserve_mutex); +} + +static int ttm_mem_io_evict(struct ttm_mem_type_manager *man) +{ + struct ttm_buffer_object *bo; + + if (!man->use_io_reserve_lru || list_empty(&man->io_reserve_lru)) + return -EAGAIN; + + bo = list_first_entry(&man->io_reserve_lru, + struct ttm_buffer_object, + io_reserve_lru); + list_del_init(&bo->io_reserve_lru); + ttm_bo_unmap_virtual_locked(bo); + + return 0; +} + +static int ttm_mem_io_reserve(struct ttm_bo_device *bdev, + struct ttm_mem_reg *mem) +{ + struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type]; + int ret = 0; + + if (!bdev->driver->io_mem_reserve) + return 0; + if (likely(man->io_reserve_fastpath)) + return bdev->driver->io_mem_reserve(bdev, mem); + + if (bdev->driver->io_mem_reserve && + mem->bus.io_reserved_count++ == 0) { +retry: ret = bdev->driver->io_mem_reserve(bdev, mem); + if (ret == -EAGAIN) { + ret = ttm_mem_io_evict(man); + if (ret == 0) + goto retry; + } + } + return ret; +} + +static void ttm_mem_io_free(struct ttm_bo_device *bdev, + struct ttm_mem_reg *mem) +{ + struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type]; + + if (likely(man->io_reserve_fastpath)) + return; + + if (bdev->driver->io_mem_reserve && + --mem->bus.io_reserved_count == 0 && + bdev->driver->io_mem_free) + bdev->driver->io_mem_free(bdev, mem); + +} + +int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo) +{ + struct ttm_mem_reg *mem = &bo->mem; + int ret; + + if (!mem->bus.io_reserved_vm) { + struct ttm_mem_type_manager *man = + &bo->bdev->man[mem->mem_type]; + + ret = ttm_mem_io_reserve(bo->bdev, mem); if (unlikely(ret != 0)) return ret; + mem->bus.io_reserved_vm = true; + if (man->use_io_reserve_lru) + list_add_tail(&bo->io_reserve_lru, + &man->io_reserve_lru); } return 0; }

-void ttm_mem_io_free(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem) +void ttm_mem_io_free_vm(struct ttm_buffer_object *bo) { - if (bdev->driver->io_mem_reserve) { - if (mem->bus.io_reserved) { - mem->bus.io_reserved = false; - bdev->driver->io_mem_free(bdev, mem); - } + struct ttm_mem_reg *mem = &bo->mem; + + if (mem->bus.io_reserved_vm) { + mem->bus.io_reserved_vm = false; + list_del_init(&bo->io_reserve_lru); + ttm_mem_io_free(bo->bdev, mem); } }

int ttm_mem_reg_ioremap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem, void **virtual) { + struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type]; int ret; void *addr;

*virtual = NULL; + (void) ttm_mem_io_lock(man, false); ret = ttm_mem_io_reserve(bdev, mem); + ttm_mem_io_unlock(man); if (ret || !mem->bus.is_iomem) return ret;

@@ -117,7 +203,9 @@ int ttm_mem_reg_ioremap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem, else addr = ioremap_nocache(mem->bus.base + mem->bus.offset, mem->bus.size); if (!addr) { + (void) ttm_mem_io_lock(man, false); ttm_mem_io_free(bdev, mem); + ttm_mem_io_unlock(man); return -ENOMEM; } } @@ -134,7 +222,9 @@ void ttm_mem_reg_iounmap(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem,

if (virtual && mem->bus.addr == NULL) iounmap(virtual); + (void) ttm_mem_io_lock(man, false); ttm_mem_io_free(bdev, mem); + ttm_mem_io_unlock(man); }

static int ttm_copy_io_page(void *dst, void *src, unsigned long page) @@ -231,7 +321,7 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo, struct ttm_mem_type_manager *man = &bdev->man[new_mem->mem_type]; struct ttm_tt *ttm = bo->ttm; struct ttm_mem_reg *old_mem = &bo->mem; - struct ttm_mem_reg old_copy = *old_mem; + struct ttm_mem_reg old_copy; void *old_iomap; void *new_iomap; int ret; @@ -281,7 +371,7 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo, mb(); out2: ttm_bo_free_old_node(bo); - + old_copy = *old_mem; *old_mem = *new_mem; new_mem->mm_node = NULL;

@@ -292,7 +382,7 @@ out2: }

out1: - ttm_mem_reg_iounmap(bdev, new_mem, new_iomap); + ttm_mem_reg_iounmap(bdev, old_mem, new_iomap); out: ttm_mem_reg_iounmap(bdev, &old_copy, old_iomap); return ret; @@ -342,6 +432,7 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo, INIT_LIST_HEAD(&fbo->ddestroy); INIT_LIST_HEAD(&fbo->lru); INIT_LIST_HEAD(&fbo->swap); + INIT_LIST_HEAD(&fbo->io_reserve_lru); fbo->vm_node = NULL; atomic_set(&fbo->cpu_writers, 0);

@@ -453,6 +544,8 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page, unsigned long num_pages, struct ttm_bo_kmap_obj *map) { + struct ttm_mem_type_manager *man = + &bo->bdev->man[bo->mem.mem_type]; unsigned long offset, size; int ret;

@@ -467,7 +560,9 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo, if (num_pages > 1 && !DRM_SUSER(DRM_CURPROC)) return -EPERM; #endif + (void) ttm_mem_io_lock(man, false); ret = ttm_mem_io_reserve(bo->bdev, &bo->mem); + ttm_mem_io_unlock(man); if (ret) return ret; if (!bo->mem.bus.is_iomem) { @@ -482,12 +577,15 @@ EXPORT_SYMBOL(ttm_bo_kmap);

void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map) { + struct ttm_buffer_object *bo = map->bo; + struct ttm_mem_type_manager *man = + &bo->bdev->man[bo->mem.mem_type]; + if (!map->virtual) return; switch (map->bo_kmap_type) { case ttm_bo_map_iomap: iounmap(map->virtual); - ttm_mem_io_free(map->bo->bdev, &map->bo->mem); break; case ttm_bo_map_vmap: vunmap(map->virtual); @@ -500,6 +598,9 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map) default: BUG(); } + (void) ttm_mem_io_lock(man, false); + ttm_mem_io_free(map->bo->bdev, &map->bo->mem); + ttm_mem_io_unlock(man); map->virtual = NULL; map->page = NULL; } diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index fe6cb77..73202cb 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -83,6 +83,8 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) int i; unsigned long address = (unsigned long)vmf->virtual_address; int retval = VM_FAULT_NOPAGE; + struct ttm_mem_type_manager *man = + &bdev->man[bo->mem.mem_type];

/* * Work around locking order reversal in fault / nopfn @@ -130,12 +132,16 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) } else spin_unlock(&bo->lock);

- - ret = ttm_mem_io_reserve(bdev, &bo->mem); - if (ret) { - retval = VM_FAULT_SIGBUS; + ret = ttm_mem_io_lock(man, true); + if (unlikely(ret != 0)) { + retval = VM_FAULT_NOPAGE; goto out_unlock; } + ret = ttm_mem_io_reserve_vm(bo); + if (unlikely(ret != 0)) { + retval = VM_FAULT_SIGBUS; + goto out_io_unlock; + }

page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) + bo->vm_node->start - vma->vm_pgoff; @@ -144,7 +150,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)

if (unlikely(page_offset >= bo->num_pages)) { retval = VM_FAULT_SIGBUS; - goto out_unlock; + goto out_io_unlock; }

/* @@ -182,7 +188,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) page = ttm_tt_get_page(ttm, page_offset); if (unlikely(!page && i == 0)) { retval = VM_FAULT_OOM; - goto out_unlock; + goto out_io_unlock; } else if (unlikely(!page)) { break; } @@ -200,14 +206,15 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) else if (unlikely(ret != 0)) { retval = (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS; - goto out_unlock; + goto out_io_unlock; }

address += PAGE_SIZE; if (unlikely(++page_offset >= page_last)) break; } - +out_io_unlock: + ttm_mem_io_unlock(man); out_unlock: ttm_bo_unreserve(bo); return retval; diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index beafc15..5510a8c 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -74,6 +74,8 @@ struct ttm_placement { * @is_iomem: is this io memory ? * @size: size in byte * @offset: offset from the base address + * @io_reserved_vm: The VM system has a refcount in @io_reserved_count + * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve * * Structure indicating the bus placement of an object. */ @@ -83,7 +85,8 @@ struct ttm_bus_placement { unsigned long size; unsigned long offset; bool is_iomem; - bool io_reserved; + bool io_reserved_vm; + uint64_t io_reserved_count; };

@@ -237,6 +240,7 @@ struct ttm_buffer_object { struct list_head lru; struct list_head ddestroy; struct list_head swap; + struct list_head io_reserve_lru; uint32_t val_seq; bool seq_valid;

diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index 8e0c848..b342bb2 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -179,30 +179,6 @@ struct ttm_tt { #define TTM_MEMTYPE_FLAG_MAPPABLE (1 << 1) /* Memory mappable */ #define TTM_MEMTYPE_FLAG_CMA (1 << 3) /* Can't map aperture */

-/** - * struct ttm_mem_type_manager - * - * @has_type: The memory type has been initialized. - * @use_type: The memory type is enabled. - * @flags: TTM_MEMTYPE_XX flags identifying the traits of the memory - * managed by this memory type. - * @gpu_offset: If used, the GPU offset of the first managed page of - * fixed memory or the first managed location in an aperture. - * @size: Size of the managed region. - * @available_caching: A mask of available caching types, TTM_PL_FLAG_XX, - * as defined in ttm_placement_common.h - * @default_caching: The default caching policy used for a buffer object - * placed in this memory type if the user doesn't provide one. - * @manager: The range manager used for this memory type. FIXME: If the aperture - * has a page size different from the underlying system, the granularity - * of this manager should take care of this. But the range allocating code - * in ttm_bo.c needs to be modified for this. - * @lru: The lru list for this memory type. - * - * This structure is used to identify and manage memory types for a device. - * It's set up by the ttm_bo_driver::init_mem_type method. - */ - struct ttm_mem_type_manager;

struct ttm_mem_type_manager_func { @@ -287,6 +263,36 @@ struct ttm_mem_type_manager_func { void (*debug)(struct ttm_mem_type_manager *man, const char *prefix); };

+/** + * struct ttm_mem_type_manager + * + * @has_type: The memory type has been initialized. + * @use_type: The memory type is enabled. + * @flags: TTM_MEMTYPE_XX flags identifying the traits of the memory + * managed by this memory type. + * @gpu_offset: If used, the GPU offset of the first managed page of + * fixed memory or the first managed location in an aperture. + * @size: Size of the managed region. + * @available_caching: A mask of available caching types, TTM_PL_FLAG_XX, + * as defined in ttm_placement_common.h + * @default_caching: The default caching policy used for a buffer object + * placed in this memory type if the user doesn't provide one. + * @func: structure pointer implementing the range manager. See above + * @priv: Driver private closure for @func. + * @io_reserve_mutex: Mutex optionally protecting shared io_reserve structures + * @use_io_reserve_lru: Use an lru list to try to unreserve io_mem_regions + * reserved by the TTM vm system. + * @io_reserve_lru: Optional lru list for unreserving io mem regions. + * @io_reserve_fastpath: Only use bdev::driver::io_mem_reserve to obtain + * static information. bdev::driver::io_mem_free is never used. + * @lru: The lru list for this memory type. + * + * This structure is used to identify and manage memory types for a device. + * It's set up by the ttm_bo_driver::init_mem_type method. + */ + + + struct ttm_mem_type_manager { struct ttm_bo_device *bdev;

@@ -303,6 +309,15 @@ struct ttm_mem_type_manager { uint32_t default_caching; const struct ttm_mem_type_manager_func *func; void *priv; + struct mutex io_reserve_mutex; + bool use_io_reserve_lru; + bool io_reserve_fastpath; + + /* + * Protected by @io_reserve_mutex: + */ + + struct list_head io_reserve_lru;

/* * Protected by the global->lru_lock. @@ -753,31 +768,6 @@ extern void ttm_bo_mem_put_locked(struct ttm_buffer_object *bo,

extern int ttm_bo_wait_cpu(struct ttm_buffer_object *bo, bool no_wait);

-/** - * ttm_bo_pci_offset - Get the PCI offset for the buffer object memory. - * - * @bo Pointer to a struct ttm_buffer_object. - * @bus_base On return the base of the PCI region - * @bus_offset On return the byte offset into the PCI region - * @bus_size On return the byte size of the buffer object or zero if - * the buffer object memory is not accessible through a PCI region. - * - * Returns: - * -EINVAL if the buffer object is currently not mappable. - * 0 otherwise. - */ - -extern int ttm_bo_pci_offset(struct ttm_bo_device *bdev, - struct ttm_mem_reg *mem, - unsigned long *bus_base, - unsigned long *bus_offset, - unsigned long *bus_size); - -extern int ttm_mem_io_reserve(struct ttm_bo_device *bdev, - struct ttm_mem_reg *mem); -extern void ttm_mem_io_free(struct ttm_bo_device *bdev, - struct ttm_mem_reg *mem); - extern void ttm_bo_global_release(struct drm_global_reference *ref); extern int ttm_bo_global_init(struct drm_global_reference *ref);

@@ -810,6 +800,22 @@ extern int ttm_bo_device_init(struct ttm_bo_device *bdev, extern void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo);

/** + * ttm_bo_unmap_virtual + * + * @bo: tear down the virtual mappings for this BO + * + * The caller must take ttm_mem_io_lock before calling this function. + */ +extern void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo); + +extern int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo); +extern void ttm_mem_io_free_vm(struct ttm_buffer_object *bo); +extern int ttm_mem_io_lock(struct ttm_mem_type_manager *man, + bool interruptible); +extern void ttm_mem_io_unlock(struct ttm_mem_type_manager *man); + + +/** * ttm_bo_reserve: * * @bo: A pointer to a struct ttm_buffer_object.