[Intel-gfx] [PATCH 23/23] drm/i915/gem: Pull execbuf dma resv under a single critical section
Chris Wilson
chris at chris-wilson.co.uk
Thu Jul 2 08:32:25 UTC 2020
Acquire all the objects and their backing storage, and page directories,
as used by execbuf under a single common ww_mutex. Albeit we have to
restart the critical section a few times in order to handle various
restrictions (such as avoiding copy_(from|to)_user and mmap_sem).
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
.../gpu/drm/i915/gem/i915_gem_execbuffer.c | 146 ++++++++----------
1 file changed, 64 insertions(+), 82 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index c325aed82629..22b382053cdc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -20,6 +20,7 @@
#include "gt/intel_gt_pm.h"
#include "gt/intel_gt_requests.h"
#include "gt/intel_ring.h"
+#include "mm/i915_acquire_ctx.h"
#include "i915_drv.h"
#include "i915_gem_clflush.h"
@@ -245,6 +246,8 @@ struct i915_execbuffer {
struct intel_context *context; /* logical state for the request */
struct i915_gem_context *gem_context; /** caller's context */
+ struct i915_acquire_ctx acquire; /** lock for _all_ DMA reservations */
+
struct i915_request *request; /** our request to build */
struct eb_vma *batch; /** identity of the batch obj/vma */
@@ -385,42 +388,6 @@ static void eb_vma_array_put(struct eb_vma_array *arr)
kref_put(&arr->kref, eb_vma_array_destroy);
}
-static int
-eb_lock_vma(struct i915_execbuffer *eb, struct ww_acquire_ctx *acquire)
-{
- struct eb_vma *ev;
- int err = 0;
-
- list_for_each_entry(ev, &eb->submit_list, submit_link) {
- struct i915_vma *vma = ev->vma;
-
- err = ww_mutex_lock_interruptible(&vma->resv->lock, acquire);
- if (err == -EDEADLK) {
- struct eb_vma *unlock = ev, *en;
-
- list_for_each_entry_safe_continue_reverse(unlock, en,
- &eb->submit_list,
- submit_link) {
- ww_mutex_unlock(&unlock->vma->resv->lock);
- list_move_tail(&unlock->submit_link, &eb->submit_list);
- }
-
- GEM_BUG_ON(!list_is_first(&ev->submit_link, &eb->submit_list));
- err = ww_mutex_lock_slow_interruptible(&vma->resv->lock,
- acquire);
- }
- if (err) {
- list_for_each_entry_continue_reverse(ev,
- &eb->submit_list,
- submit_link)
- ww_mutex_unlock(&ev->vma->resv->lock);
- break;
- }
- }
-
- return err;
-}
-
static int eb_create(struct i915_execbuffer *eb)
{
/* Allocate an extra slot for use by the sentinel */
@@ -661,6 +628,31 @@ eb_add_vma(struct i915_execbuffer *eb,
}
}
+static int eb_reserve_mm(struct i915_execbuffer *eb)
+{
+ struct eb_vma *ev;
+ int err;
+
+ list_for_each_entry(ev, &eb->bind_list, bind_link) {
+ err = i915_acquire_ctx_lock(&eb->acquire, ev->vma->obj);
+ if (err == -EDEADLK) {
+ struct eb_vma *unlock = ev, *en;
+
+ list_for_each_entry_safe_continue_reverse(unlock, en,
+ &eb->bind_list,
+ bind_link)
+ list_move_tail(&unlock->bind_link,
+ &eb->bind_list);
+
+ err = i915_acquire_ctx_backoff(&eb->acquire);
+ }
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
struct eb_vm_work {
struct dma_fence_work base;
struct eb_vma_array *array;
@@ -1338,10 +1330,13 @@ static int eb_prepare_vma(struct eb_vm_work *work,
if (ev->flags & __EXEC_OBJECT_NEEDS_MAP)
max_size = max_t(u64, max_size, vma->fence_size);
+ /* XXX pass eb->acquire to pt_stash for its DMA resv */
err = i915_vm_alloc_pt_stash(work->vm, &work->stash, max_size);
+ GEM_BUG_ON(err == -EDEADLK); /* all fresh, no contention */
if (err)
return err;
+ /* XXX just setup vma->pages, holding obj->pages under ww_mutex */
return i915_vma_get_pages(vma);
}
@@ -1402,7 +1397,11 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
unsigned long count;
unsigned int pass;
struct eb_vma *ev;
- int err = 0;
+ int err;
+
+ err = eb_reserve_mm(eb);
+ if (err)
+ return err;
count = 0;
INIT_LIST_HEAD(&unbound);
@@ -1533,6 +1532,8 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
if (signal_pending(current))
return -EINTR;
+ i915_acquire_ctx_fini(&eb->acquire);
+
/* Now safe to wait with no reservations held */
if (err == -EAGAIN) {
@@ -1541,6 +1542,9 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
}
err = wait_for_unbinds(eb, &unbound, pass++);
+ i915_acquire_ctx_init(&eb->acquire);
+ if (err == 0)
+ err = eb_reserve_mm(eb);
if (err)
return err;
} while (1);
@@ -1948,8 +1952,6 @@ static int reloc_move_to_gpu(struct i915_request *rq, struct i915_vma *vma)
struct drm_i915_gem_object *obj = vma->obj;
int err;
- i915_vma_lock(vma);
-
if (obj->cache_dirty & ~obj->cache_coherent)
i915_gem_clflush_object(obj, 0);
obj->write_domain = 0;
@@ -1958,8 +1960,6 @@ static int reloc_move_to_gpu(struct i915_request *rq, struct i915_vma *vma)
if (err == 0)
err = i915_vma_move_to_active(vma, rq, EXEC_OBJECT_WRITE);
- i915_vma_unlock(vma);
-
return err;
}
@@ -2223,6 +2223,7 @@ static int eb_relocs_copy_user(struct i915_execbuffer *eb)
/* Drop everything before we copy_from_user */
list_for_each_entry(ev, &eb->bind_list, bind_link)
eb_unreserve_vma(ev);
+ i915_acquire_ctx_fini(&eb->acquire);
eb->reloc_cache.head.vma = NULL;
eb->reloc_cache.pos = N_RELOC;
@@ -2230,9 +2231,13 @@ static int eb_relocs_copy_user(struct i915_execbuffer *eb)
list_for_each_entry(ev, &eb->relocs, reloc_link) {
err = eb_relocs_copy_vma(eb, ev);
if (err)
- return err;
+ break;
}
+ i915_acquire_ctx_init(&eb->acquire);
+ if (err)
+ return err;
+
/* Now reacquire everything, including the extra reloc bo */
return eb_reserve_vm(eb);
}
@@ -2275,11 +2280,9 @@ get_gpu_relocs(struct i915_execbuffer *eb,
struct i915_vma *vma = c->head.vma;
int err;
- i915_vma_lock(vma);
err = i915_request_await_object(rq, vma->obj, false);
if (err == 0)
err = i915_vma_move_to_active(vma, rq, 0);
- i915_vma_unlock(vma);
if (err)
return ERR_PTR(err);
@@ -2434,17 +2437,8 @@ static int eb_relocate(struct i915_execbuffer *eb)
static int eb_move_to_gpu(struct i915_execbuffer *eb)
{
- struct ww_acquire_ctx acquire;
struct eb_vma *ev;
- int err = 0;
-
- ww_acquire_init(&acquire, &reservation_ww_class);
-
- err = eb_lock_vma(eb, &acquire);
- if (err)
- goto err_fini;
-
- ww_acquire_done(&acquire);
+ int err;
list_for_each_entry(ev, &eb->submit_list, submit_link) {
struct i915_vma *vma = ev->vma;
@@ -2481,27 +2475,22 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
flags &= ~EXEC_OBJECT_ASYNC;
}
- if (err == 0 && !(flags & EXEC_OBJECT_ASYNC)) {
+ if (!(flags & EXEC_OBJECT_ASYNC)) {
err = i915_request_await_object
(eb->request, obj, flags & EXEC_OBJECT_WRITE);
+ if (unlikely(err))
+ goto err_skip;
}
- if (err == 0)
- err = i915_vma_move_to_active(vma, eb->request, flags);
-
- i915_vma_unlock(vma);
+ err = i915_vma_move_to_active(vma, eb->request, flags);
+ if (unlikely(err))
+ goto err_skip;
}
- ww_acquire_fini(&acquire);
-
- if (unlikely(err))
- goto err_skip;
/* Unconditionally flush any chipset caches (for streaming writes). */
intel_gt_chipset_flush(eb->engine->gt);
return 0;
-err_fini:
- ww_acquire_fini(&acquire);
err_skip:
i915_request_set_error_once(eb->request, err);
return err;
@@ -2653,39 +2642,27 @@ static int eb_parse_pipeline(struct i915_execbuffer *eb,
/* Mark active refs early for this worker, in case we get interrupted */
err = parser_mark_active(pw, eb->context->timeline);
if (err)
- goto err_commit;
-
- err = dma_resv_lock_interruptible(pw->batch->resv, NULL);
- if (err)
- goto err_commit;
+ goto out;
err = dma_resv_reserve_shared(pw->batch->resv, 1);
if (err)
- goto err_commit_unlock;
+ goto out;
/* Wait for all writes (and relocs) into the batch to complete */
err = i915_sw_fence_await_reservation(&pw->base.chain,
pw->batch->resv, NULL, false,
0, I915_FENCE_GFP);
if (err < 0)
- goto err_commit_unlock;
+ goto out;
/* Keep the batch alive and unwritten as we parse */
dma_resv_add_shared_fence(pw->batch->resv, &pw->base.dma);
- dma_resv_unlock(pw->batch->resv);
-
/* Force execution to wait for completion of the parser */
- dma_resv_lock(shadow->resv, NULL);
dma_resv_add_excl_fence(shadow->resv, &pw->base.dma);
- dma_resv_unlock(shadow->resv);
- dma_fence_work_commit_imm(&pw->base);
- return 0;
-
-err_commit_unlock:
- dma_resv_unlock(pw->batch->resv);
-err_commit:
+ err = 0;
+out:
i915_sw_fence_set_error_once(&pw->base.chain, err);
dma_fence_work_commit_imm(&pw->base);
return err;
@@ -3309,6 +3286,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
goto err_context;
lockdep_assert_held(&eb.context->timeline->mutex);
+ i915_acquire_ctx_init(&eb.acquire);
+
err = eb_relocate(&eb);
if (err) {
/*
@@ -3322,6 +3301,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
goto err_vma;
}
+ i915_acquire_ctx_done(&eb.acquire);
+
err = eb_parse(&eb);
if (err)
goto err_vma;
@@ -3397,6 +3378,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
err_vma:
if (eb.parser.shadow)
intel_gt_buffer_pool_put(eb.parser.shadow->vma->private);
+ i915_acquire_ctx_fini(&eb.acquire);
eb_relocs_update_user(&eb);
eb_unpin_engine(&eb);
err_context:
--
2.20.1
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