[Intel-gfx] [PATCH 26/37] drm/i915/gem: Pull execbuf dma resv under a single critical section
Chris Wilson
chris at chris-wilson.co.uk
Wed Aug 5 12:22:20 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 | 166 +++++++++---------
.../i915/gem/selftests/i915_gem_execbuffer.c | 2 +
2 files changed, 84 insertions(+), 84 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 58e40348b551..3a79b6facb02 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"
@@ -267,6 +268,8 @@ struct i915_execbuffer {
struct intel_context *reloc_context; /* distinct context for relocs */
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 */
@@ -392,42 +395,6 @@ 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 */
@@ -656,6 +623,25 @@ eb_add_vma(struct i915_execbuffer *eb,
}
}
+static int eb_lock_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)
+ return err;
+ }
+
+ return 0;
+}
+
+static int eb_acquire_mm(struct i915_execbuffer *eb)
+{
+ return i915_acquire_mm(&eb->acquire);
+}
+
struct eb_vm_work {
struct dma_fence_work base;
struct eb_vma_array *array;
@@ -1378,7 +1364,15 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
unsigned long count;
struct eb_vma *ev;
unsigned int pass;
- int err = 0;
+ int err;
+
+ err = eb_lock_mm(eb);
+ if (err)
+ return err;
+
+ err = eb_acquire_mm(eb);
+ if (err)
+ return err;
count = 0;
INIT_LIST_HEAD(&unbound);
@@ -1404,10 +1398,15 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
if (count == 0)
return 0;
+ /* We need to reserve page directories, release all, start over */
+ i915_acquire_ctx_fini(&eb->acquire);
+
pass = 0;
do {
struct eb_vm_work *work;
+ i915_acquire_ctx_init(&eb->acquire);
+
/*
* We need to hold one lock as we bind all the vma so that
* we have a consistent view of the entire vm and can plan
@@ -1424,6 +1423,11 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
* beneath it, so we have to stage and preallocate all the
* resources we may require before taking the mutex.
*/
+
+ err = eb_lock_mm(eb);
+ if (err)
+ return err;
+
work = eb_vm_work(eb, count);
if (!work)
return -ENOMEM;
@@ -1441,6 +1445,10 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
}
}
+ err = eb_acquire_mm(eb);
+ if (err)
+ return eb_vm_work_cancel(work, err);
+
err = i915_vm_pin_pt_stash(work->vm, &work->stash);
if (err)
return eb_vm_work_cancel(work, err);
@@ -1531,6 +1539,8 @@ 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) {
@@ -1554,8 +1564,10 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
* total ownership of the vm.
*/
err = wait_for_unbinds(eb, &unbound, pass++);
- if (err)
+ if (err) {
+ i915_acquire_ctx_init(&eb->acquire);
return err;
+ }
} while (1);
}
@@ -2008,8 +2020,6 @@ 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;
@@ -2018,8 +2028,6 @@ 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;
}
@@ -2505,6 +2513,7 @@ static int eb_relocate(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);
/* Pick a single buffer for all relocs, within reason */
bufsz = round_up(eb->relocs_count * sz + sz, SZ_4K);
@@ -2515,6 +2524,7 @@ static int eb_relocate(struct i915_execbuffer *eb)
/* Copy the user's relocations into plain system memory */
err = eb_relocs_copy_user(eb, &relocs);
+ i915_acquire_ctx_init(&eb->acquire);
if (err)
goto out_close;
@@ -2551,17 +2561,8 @@ static int eb_reserve(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;
@@ -2600,27 +2601,22 @@ 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;
@@ -2784,39 +2780,27 @@ 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;
@@ -2856,10 +2840,6 @@ static int eb_submit(struct i915_execbuffer *eb)
{
int err;
- err = eb_move_to_gpu(eb);
- if (err)
- return err;
-
if (eb->args->flags & I915_EXEC_GEN7_SOL_RESET) {
err = i915_reset_gen7_sol_offsets(eb->request);
if (err)
@@ -3636,6 +3616,9 @@ i915_gem_do_execbuffer(struct drm_device *dev,
goto err_engine;
lockdep_assert_held(&eb.context->timeline->mutex);
+ /* *** DMA-RESV LOCK *** */
+ i915_acquire_ctx_init(&eb.acquire);
+
err = eb_reserve(&eb);
if (err) {
/*
@@ -3649,6 +3632,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
goto err_vma;
}
+ /* *** DMA-RESV SEALED *** */
+
err = eb_parse(&eb);
if (err)
goto err_vma;
@@ -3699,9 +3684,20 @@ i915_gem_do_execbuffer(struct drm_device *dev,
intel_gt_buffer_pool_mark_active(eb.parser.shadow->vma->private,
eb.request);
+ err = eb_move_to_gpu(&eb);
+ if (err)
+ goto err_request;
+
+ /* *** DMA-RESV PUBLISHED *** */
+
trace_i915_request_queue(eb.request, eb.batch_flags);
err = eb_submit(&eb);
+
err_request:
+ i915_acquire_ctx_fini(&eb.acquire);
+ eb.acquire.locked = ERR_PTR(-1);
+ /* *** DMA-RESV UNLOCK *** */
+
i915_request_get(eb.request);
eb_request_add(&eb);
@@ -3711,6 +3707,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
i915_request_put(eb.request);
err_vma:
+ if (eb.acquire.locked != ERR_PTR(-1))
+ i915_acquire_ctx_fini(&eb.acquire);
eb_unlock_engine(&eb);
/* *** TIMELINE UNLOCK *** */
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c
index df02cb8b27ed..ed140d34a678 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_execbuffer.c
@@ -116,7 +116,9 @@ static int __igt_gpu_reloc(struct i915_execbuffer *eb,
return err;
ev->exec->relocation_count = err;
+ i915_acquire_ctx_init(&eb->acquire);
err = mock_reloc_gpu(eb, relocs);
+ i915_acquire_ctx_fini(&eb->acquire);
if (err)
return err;
--
2.20.1
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