diff options
| -rw-r--r-- | src/intel/vulkan/anv_batch_chain.c | 151 | ||||
| -rw-r--r-- | src/intel/vulkan/anv_device.c | 8 |
2 files changed, 150 insertions, 9 deletions
diff --git a/src/intel/vulkan/anv_batch_chain.c b/src/intel/vulkan/anv_batch_chain.c index 3493eeb..b49e173 100644 --- a/src/intel/vulkan/anv_batch_chain.c +++ b/src/intel/vulkan/anv_batch_chain.c @@ -32,6 +32,8 @@ #include "genxml/gen7_pack.h" #include "genxml/gen8_pack.h" +#include "util/debug.h" + /** \file anv_batch_chain.c * * This file contains functions related to anv_cmd_buffer as a data @@ -1044,6 +1046,108 @@ adjust_relocations_to_state_pool(struct anv_block_pool *pool, } } +static void +anv_reloc_list_apply(struct anv_device *device, + struct anv_reloc_list *list, + struct anv_bo *bo, + bool always_relocate) +{ + for (size_t i = 0; i < list->num_relocs; i++) { + struct anv_bo *target_bo = list->reloc_bos[i]; + if (list->relocs[i].presumed_offset == target_bo->offset && + !always_relocate) + continue; + + void *p = bo->map + list->relocs[i].offset; + write_reloc(device, p, target_bo->offset + list->relocs[i].delta, true); + list->relocs[i].presumed_offset = target_bo->offset; + } +} + +/** + * This function applies the relocation for a command buffer and writes the + * actual addresses into the buffers as per what we were told by the kernel on + * the previous execbuf2 call. This should be safe to do because, for each + * relocated address, we have two cases: + * + * 1) The target BO is inactive (as seen by the kernel). In this case, it is + * not in use by the GPU so updating the address is 100% ok. It won't be + * in-use by the GPU (from our context) again until the next execbuf2 + * happens. If the kernel decides to move it in the next execbuf2, it + * will have to do the relocations itself, but that's ok because it should + * have all of the information needed to do so. + * + * 2) The target BO is active (as seen by the kernel). In this case, it + * hasn't moved since the last execbuffer2 call because GTT shuffling + * *only* happens when the BO is idle. (From our perspective, it only + * happens inside the execbuffer2 ioctl, but the shuffling may be + * triggered by another ioctl, with full-ppgtt this is limited to only + * execbuffer2 ioctls on the same context, or memory pressure.) Since the + * target BO hasn't moved, our anv_bo::offset exactly matches the BO's GTT + * address and the relocated value we are writing into the BO will be the + * same as the value that is already there. + * + * There is also a possibility that the target BO is active but the exact + * RENDER_SURFACE_STATE object we are writing the relocation into isn't in + * use. In this case, the address currently in the RENDER_SURFACE_STATE + * may be stale but it's still safe to write the relocation because that + * particular RENDER_SURFACE_STATE object isn't in-use by the GPU and + * won't be until the next execbuf2 call. + * + * By doing relocations on the CPU, we can tell the kernel that it doesn't + * need to bother. We want to do this because the surface state buffer is + * used by every command buffer so, if the kernel does the relocations, it + * will always be busy and the kernel will always stall. This is also + * probably the fastest mechanism for doing relocations since the kernel would + * have to make a full copy of all the relocations lists. + */ +static bool +relocate_cmd_buffer(struct anv_cmd_buffer *cmd_buffer, + struct anv_execbuf *exec) +{ + static int userspace_relocs = -1; + if (userspace_relocs < 0) + userspace_relocs = env_var_as_boolean("ANV_USERSPACE_RELOCS", true); + if (!userspace_relocs) + return false; + + /* First, we have to check to see whether or not we can even do the + * relocation. New buffers which have never been submitted to the kernel + * don't have a valid offset so we need to let the kernel do relocations so + * that we can get offsets for them. On future execbuf2 calls, those + * buffers will have offsets and we will be able to skip relocating. + * Invalid offsets are indicated by anv_bo::offset == (uint64_t)-1. + */ + for (uint32_t i = 0; i < exec->bo_count; i++) { + if (exec->bos[i]->offset == (uint64_t)-1) + return false; + } + + /* Since surface states are shared between command buffers and we don't + * know what order they will be submitted to the kernel, we don't know + * what address is actually written in the surface state object at any + * given time. The only option is to always relocate them. + */ + anv_reloc_list_apply(cmd_buffer->device, &cmd_buffer->surface_relocs, + &cmd_buffer->device->surface_state_block_pool.bo, + true /* always relocate surface states */); + + /* Since we own all of the batch buffers, we know what values are stored + * in the relocated addresses and only have to update them if the offsets + * have changed. + */ + struct anv_batch_bo **bbo; + u_vector_foreach(bbo, &cmd_buffer->seen_bbos) { + anv_reloc_list_apply(cmd_buffer->device, + &(*bbo)->relocs, &(*bbo)->bo, false); + } + + for (uint32_t i = 0; i < exec->bo_count; i++) + exec->objects[i].offset = exec->bos[i]->offset; + + return true; +} + VkResult anv_cmd_buffer_execbuf(struct anv_device *device, struct anv_cmd_buffer *cmd_buffer) @@ -1134,14 +1238,45 @@ anv_cmd_buffer_execbuf(struct anv_device *device, .rsvd2 = 0, }; - /* Since surface states are shared between command buffers and we don't - * know what order they will be submitted to the kernel, we don't know what - * address is actually written in the surface state object at any given - * time. The only option is to set a bogus presumed offset and let - * relocations do their job. - */ - for (size_t i = 0; i < cmd_buffer->surface_relocs.num_relocs; i++) - cmd_buffer->surface_relocs.relocs[i].presumed_offset = -1; + if (relocate_cmd_buffer(cmd_buffer, &execbuf)) { + /* If we were able to successfully relocate everything, tell the kernel + * that it can skip doing relocations. The requirement for using + * NO_RELOC is: + * + * 1) The addresses written in the objects must match the corresponding + * reloc.presumed_offset which in turn must match the corresponding + * execobject.offset. + * + * 2) To avoid stalling, execobject.offset should match the current + * address of that object within the active context. + * + * In order to satisfy all of the invariants that make userspace + * relocations to be safe (see relocate_cmd_buffer()), we need to + * further ensure that the addresses we use match those used by the + * kernel for the most recent execbuf2. + * + * The kernel may still choose to do relocations anyway if something has + * moved in the GTT. In this case, the relocation list still needs to be + * valid. All relocations on the batch buffers are already valid and + * kept up-to-date. For surface state relocations, by applying the + * relocations in relocate_cmd_buffer, we ensured that the address in + * the RENDER_SURFACE_STATE matches presumed_offset, so it should be + * safe for the kernel to relocate them as needed. + */ + execbuf.execbuf.flags |= I915_EXEC_NO_RELOC; + } else { + /* In the case where we fall back to doing kernel relocations, we need + * to ensure that the relocation list is valid. All relocations on the + * batch buffers are already valid and kept up-to-date. Since surface + * states are shared between command buffers and we don't know what + * order they will be submitted to the kernel, we don't know what + * address is actually written in the surface state object at any given + * time. The only option is to set a bogus presumed offset and let the + * kernel relocate them. + */ + for (size_t i = 0; i < cmd_buffer->surface_relocs.num_relocs; i++) + cmd_buffer->surface_relocs.relocs[i].presumed_offset = -1; + } VkResult result = anv_device_execbuf(device, &execbuf.execbuf, execbuf.bos); diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c index c47961e..6b2676b 100644 --- a/src/intel/vulkan/anv_device.c +++ b/src/intel/vulkan/anv_device.c @@ -1097,7 +1097,7 @@ VkResult anv_QueueSubmit( struct anv_device *device = queue->device; VkResult result = VK_SUCCESS; - /* We lock around QueueSubmit for two main reasons: + /* We lock around QueueSubmit for three main reasons: * * 1) When a block pool is resized, we create a new gem handle with a * different size and, in the case of surface states, possibly a @@ -1112,6 +1112,12 @@ VkResult anv_QueueSubmit( * came up in the wild due to a broken app. It's better to play it * safe and just lock around QueueSubmit. * + * 3) The anv_cmd_buffer_execbuf function may perform relocations in + * userspace. Due to the fact that the surface state buffer is shared + * between batches, we can't afford to have that happen from multiple + * threads at the same time. Even though the user is supposed to + * ensure this doesn't happen, we play it safe as in (2) above. + * * Since the only other things that ever take the device lock such as block * pool resize only rarely happen, this will almost never be contended so * taking a lock isn't really an expensive operation in this case. |