[Intel-gfx] [PATCH v2 1/7] drm/i915: Avoid using the i915_fence_array when collecting dependencies
Thomas Hellström
thomas.hellstrom at linux.intel.com
Fri Dec 17 09:19:23 UTC 2021
Since the gt migration code was using only a single fence for
dependencies, these were collected in a dma_fence_array. However, it
turns out that it's illegal to use some dma_fences in a dma_fence_array,
in particular other dma_fence_arrays and dma_fence_chains, and this
causes trouble for us moving forward.
Have the gt migration code instead take a const struct i915_deps for
dependencies. This means we can skip the dma_fence_array creation
and instead pass the struct i915_deps instead to circumvent the
problem.
v2:
- Make the prev_deps() function static. (kernel test robot <lkp at intel.com>)
- Update the struct i915_deps kerneldoc.
Fixes: 5652df829b3c ("drm/i915/ttm: Update i915_gem_obj_copy_ttm() to be asynchronous")
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 129 +++++--------------
drivers/gpu/drm/i915/gem/i915_gem_ttm_move.h | 17 +++
drivers/gpu/drm/i915/gt/intel_migrate.c | 24 ++--
drivers/gpu/drm/i915/gt/intel_migrate.h | 9 +-
drivers/gpu/drm/i915/i915_request.c | 22 ++++
drivers/gpu/drm/i915/i915_request.h | 2 +
6 files changed, 91 insertions(+), 112 deletions(-)
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 80df9f592407..960145c8200f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -3,8 +3,6 @@
* Copyright © 2021 Intel Corporation
*/
-#include <linux/dma-fence-array.h>
-
#include <drm/ttm/ttm_bo_driver.h>
#include "i915_drv.h"
@@ -44,17 +42,12 @@ void i915_ttm_migrate_set_failure_modes(bool gpu_migration,
#endif
/**
- * DOC: Set of utilities to dynamically collect dependencies and
- * eventually coalesce them into a single fence which is fed into
- * the GT migration code, since it only accepts a single dependency
- * fence.
- * The single fence returned from these utilities, in the case of
- * dependencies from multiple fence contexts, a struct dma_fence_array,
- * since the i915 request code can break that up and await the individual
- * fences.
+ * DOC: Set of utilities to dynamically collect dependencies into a
+ * structure which is fed into the GT migration code.
*
* Once we can do async unbinding, this is also needed to coalesce
- * the migration fence with the unbind fences.
+ * the migration fence with the unbind fences if these are coalesced
+ * post-migration.
*
* While collecting the individual dependencies, we store the refcounted
* struct dma_fence pointers in a realloc-managed pointer array, since
@@ -65,32 +58,13 @@ void i915_ttm_migrate_set_failure_modes(bool gpu_migration,
* A struct i915_deps need to be initialized using i915_deps_init().
* If i915_deps_add_dependency() or i915_deps_add_resv() return an
* error code they will internally call i915_deps_fini(), which frees
- * all internal references and allocations. After a call to
- * i915_deps_to_fence(), or i915_deps_sync(), the struct should similarly
- * be viewed as uninitialized.
+ * all internal references and allocations.
*
* We might want to break this out into a separate file as a utility.
*/
#define I915_DEPS_MIN_ALLOC_CHUNK 8U
-/**
- * struct i915_deps - Collect dependencies into a single dma-fence
- * @single: Storage for pointer if the collection is a single fence.
- * @fence: Allocated array of fence pointers if more than a single fence;
- * otherwise points to the address of @single.
- * @num_deps: Current number of dependency fences.
- * @fences_size: Size of the @fences array in number of pointers.
- * @gfp: Allocation mode.
- */
-struct i915_deps {
- struct dma_fence *single;
- struct dma_fence **fences;
- unsigned int num_deps;
- unsigned int fences_size;
- gfp_t gfp;
-};
-
static void i915_deps_reset_fences(struct i915_deps *deps)
{
if (deps->fences != &deps->single)
@@ -163,7 +137,7 @@ static int i915_deps_grow(struct i915_deps *deps, struct dma_fence *fence,
return ret;
}
-static int i915_deps_sync(struct i915_deps *deps,
+static int i915_deps_sync(const struct i915_deps *deps,
const struct ttm_operation_ctx *ctx)
{
struct dma_fence **fences = deps->fences;
@@ -183,7 +157,6 @@ static int i915_deps_sync(struct i915_deps *deps,
break;
}
- i915_deps_fini(deps);
return ret;
}
@@ -221,34 +194,6 @@ static int i915_deps_add_dependency(struct i915_deps *deps,
return i915_deps_grow(deps, fence, ctx);
}
-static struct dma_fence *i915_deps_to_fence(struct i915_deps *deps,
- const struct ttm_operation_ctx *ctx)
-{
- struct dma_fence_array *array;
-
- if (deps->num_deps == 0)
- return NULL;
-
- if (deps->num_deps == 1) {
- deps->num_deps = 0;
- return deps->fences[0];
- }
-
- /*
- * TODO: Alter the allocation mode here to not try too hard to
- * make things async.
- */
- array = dma_fence_array_create(deps->num_deps, deps->fences, 0, 0,
- false);
- if (!array)
- return ERR_PTR(i915_deps_sync(deps, ctx));
-
- deps->fences = NULL;
- i915_deps_reset_fences(deps);
-
- return &array->base;
-}
-
static int i915_deps_add_resv(struct i915_deps *deps, struct dma_resv *resv,
bool all, const bool no_excl,
const struct ttm_operation_ctx *ctx)
@@ -387,7 +332,7 @@ static struct dma_fence *i915_ttm_accel_move(struct ttm_buffer_object *bo,
struct ttm_resource *dst_mem,
struct ttm_tt *dst_ttm,
struct sg_table *dst_st,
- struct dma_fence *dep)
+ const struct i915_deps *deps)
{
struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915),
bdev);
@@ -411,7 +356,7 @@ static struct dma_fence *i915_ttm_accel_move(struct ttm_buffer_object *bo,
return ERR_PTR(-EINVAL);
intel_engine_pm_get(i915->gt.migrate.context->engine);
- ret = intel_context_migrate_clear(i915->gt.migrate.context, dep,
+ ret = intel_context_migrate_clear(i915->gt.migrate.context, deps,
dst_st->sgl, dst_level,
i915_ttm_gtt_binds_lmem(dst_mem),
0, &rq);
@@ -425,7 +370,7 @@ static struct dma_fence *i915_ttm_accel_move(struct ttm_buffer_object *bo,
src_level = i915_ttm_cache_level(i915, bo->resource, src_ttm);
intel_engine_pm_get(i915->gt.migrate.context->engine);
ret = intel_context_migrate_copy(i915->gt.migrate.context,
- dep, src_rsgt->table.sgl,
+ deps, src_rsgt->table.sgl,
src_level,
i915_ttm_gtt_binds_lmem(bo->resource),
dst_st->sgl, dst_level,
@@ -610,10 +555,11 @@ i915_ttm_memcpy_work_arm(struct i915_ttm_memcpy_work *work,
}
static struct dma_fence *
-__i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
+__i915_ttm_move(struct ttm_buffer_object *bo,
+ const struct ttm_operation_ctx *ctx, bool clear,
struct ttm_resource *dst_mem, struct ttm_tt *dst_ttm,
struct i915_refct_sgt *dst_rsgt, bool allow_accel,
- struct dma_fence *move_dep)
+ const struct i915_deps *move_deps)
{
struct i915_ttm_memcpy_work *copy_work = NULL;
struct i915_ttm_memcpy_arg _arg, *arg = &_arg;
@@ -621,7 +567,7 @@ __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
if (allow_accel) {
fence = i915_ttm_accel_move(bo, clear, dst_mem, dst_ttm,
- &dst_rsgt->table, move_dep);
+ &dst_rsgt->table, move_deps);
/*
* We only need to intercept the error when moving to lmem.
@@ -655,8 +601,8 @@ __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
if (!IS_ERR(fence))
goto out;
- } else if (move_dep) {
- int err = dma_fence_wait(move_dep, true);
+ } else if (move_deps) {
+ int err = i915_deps_sync(move_deps, ctx);
if (err)
return ERR_PTR(err);
@@ -680,29 +626,21 @@ __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
return fence;
}
-static struct dma_fence *prev_fence(struct ttm_buffer_object *bo,
- struct ttm_operation_ctx *ctx)
+static int
+prev_deps(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
+ struct i915_deps *deps)
{
- struct i915_deps deps;
int ret;
- /*
- * Instead of trying hard with GFP_KERNEL to allocate memory,
- * the dependency collection will just sync if it doesn't
- * succeed.
- */
- i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
- ret = i915_deps_add_dependency(&deps, bo->moving, ctx);
+ ret = i915_deps_add_dependency(deps, bo->moving, ctx);
if (!ret)
/*
* TODO: Only await excl fence here, and shared fences before
* signaling the migration fence.
*/
- ret = i915_deps_add_resv(&deps, bo->base.resv, true, false, ctx);
- if (ret)
- return ERR_PTR(ret);
+ ret = i915_deps_add_resv(deps, bo->base.resv, true, false, ctx);
- return i915_deps_to_fence(&deps, ctx);
+ return ret;
}
/**
@@ -756,16 +694,18 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
clear = !i915_ttm_cpu_maps_iomem(bo->resource) && (!ttm || !ttm_tt_is_populated(ttm));
if (!(clear && ttm && !(ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC))) {
- struct dma_fence *dep = prev_fence(bo, ctx);
+ struct i915_deps deps;
- if (IS_ERR(dep)) {
+ i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
+ ret = prev_deps(bo, ctx, &deps);
+ if (ret) {
i915_refct_sgt_put(dst_rsgt);
- return PTR_ERR(dep);
+ return ret;
}
- migration_fence = __i915_ttm_move(bo, clear, dst_mem, bo->ttm,
- dst_rsgt, true, dep);
- dma_fence_put(dep);
+ migration_fence = __i915_ttm_move(bo, ctx, clear, dst_mem, bo->ttm,
+ dst_rsgt, true, &deps);
+ i915_deps_fini(&deps);
}
/* We can possibly get an -ERESTARTSYS here */
@@ -826,7 +766,7 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
.interruptible = intr,
};
struct i915_refct_sgt *dst_rsgt;
- struct dma_fence *copy_fence, *dep_fence;
+ struct dma_fence *copy_fence;
struct i915_deps deps;
int ret, shared_err;
@@ -847,15 +787,12 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
if (ret)
return ret;
- dep_fence = i915_deps_to_fence(&deps, &ctx);
- if (IS_ERR(dep_fence))
- return PTR_ERR(dep_fence);
-
dst_rsgt = i915_ttm_resource_get_st(dst, dst_bo->resource);
- copy_fence = __i915_ttm_move(src_bo, false, dst_bo->resource,
+ copy_fence = __i915_ttm_move(src_bo, &ctx, false, dst_bo->resource,
dst_bo->ttm, dst_rsgt, allow_accel,
- dep_fence);
+ &deps);
+ i915_deps_fini(&deps);
i915_refct_sgt_put(dst_rsgt);
if (IS_ERR_OR_NULL(copy_fence))
return PTR_ERR_OR_ZERO(copy_fence);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.h b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.h
index d2e7f149e05c..138b7647a558 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.h
@@ -18,6 +18,23 @@ struct ttm_tt;
struct drm_i915_gem_object;
struct i915_refct_sgt;
+/**
+ * struct i915_deps - Collect dependencies into a single dma-fence
+ * @single: Storage for pointer if the collection is a single fence.
+ * @fences: Allocated array of fence pointers if more than a single fence;
+ * otherwise points to the address of @single.
+ * @num_deps: Current number of dependency fences.
+ * @fences_size: Size of the @fences array in number of pointers.
+ * @gfp: Allocation mode.
+ */
+struct i915_deps {
+ struct dma_fence *single;
+ struct dma_fence **fences;
+ unsigned int num_deps;
+ unsigned int fences_size;
+ gfp_t gfp;
+};
+
int i915_ttm_move_notify(struct ttm_buffer_object *bo);
I915_SELFTEST_DECLARE(void i915_ttm_migrate_set_failure_modes(bool gpu_migration,
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c
index 19a01878fee3..18b44af56969 100644
--- a/drivers/gpu/drm/i915/gt/intel_migrate.c
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
@@ -404,7 +404,7 @@ static int emit_copy(struct i915_request *rq, int size)
int
intel_context_migrate_copy(struct intel_context *ce,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *src,
enum i915_cache_level src_cache_level,
bool src_is_lmem,
@@ -431,8 +431,8 @@ intel_context_migrate_copy(struct intel_context *ce,
goto out_ce;
}
- if (await) {
- err = i915_request_await_dma_fence(rq, await);
+ if (deps) {
+ err = i915_request_await_deps(rq, deps);
if (err)
goto out_rq;
@@ -442,7 +442,7 @@ intel_context_migrate_copy(struct intel_context *ce,
goto out_rq;
}
- await = NULL;
+ deps = NULL;
}
/* The PTE updates + copy must not be interrupted. */
@@ -525,7 +525,7 @@ static int emit_clear(struct i915_request *rq, int size, u32 value)
int
intel_context_migrate_clear(struct intel_context *ce,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *sg,
enum i915_cache_level cache_level,
bool is_lmem,
@@ -550,8 +550,8 @@ intel_context_migrate_clear(struct intel_context *ce,
goto out_ce;
}
- if (await) {
- err = i915_request_await_dma_fence(rq, await);
+ if (deps) {
+ err = i915_request_await_deps(rq, deps);
if (err)
goto out_rq;
@@ -561,7 +561,7 @@ intel_context_migrate_clear(struct intel_context *ce,
goto out_rq;
}
- await = NULL;
+ deps = NULL;
}
/* The PTE updates + clear must not be interrupted. */
@@ -599,7 +599,7 @@ intel_context_migrate_clear(struct intel_context *ce,
int intel_migrate_copy(struct intel_migrate *m,
struct i915_gem_ww_ctx *ww,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *src,
enum i915_cache_level src_cache_level,
bool src_is_lmem,
@@ -624,7 +624,7 @@ int intel_migrate_copy(struct intel_migrate *m,
if (err)
goto out;
- err = intel_context_migrate_copy(ce, await,
+ err = intel_context_migrate_copy(ce, deps,
src, src_cache_level, src_is_lmem,
dst, dst_cache_level, dst_is_lmem,
out);
@@ -638,7 +638,7 @@ int intel_migrate_copy(struct intel_migrate *m,
int
intel_migrate_clear(struct intel_migrate *m,
struct i915_gem_ww_ctx *ww,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *sg,
enum i915_cache_level cache_level,
bool is_lmem,
@@ -661,7 +661,7 @@ intel_migrate_clear(struct intel_migrate *m,
if (err)
goto out;
- err = intel_context_migrate_clear(ce, await, sg, cache_level,
+ err = intel_context_migrate_clear(ce, deps, sg, cache_level,
is_lmem, value, out);
intel_context_unpin(ce);
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.h b/drivers/gpu/drm/i915/gt/intel_migrate.h
index 4e18e755a00b..ccc677ec4aa3 100644
--- a/drivers/gpu/drm/i915/gt/intel_migrate.h
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.h
@@ -11,6 +11,7 @@
#include "intel_migrate_types.h"
struct dma_fence;
+struct i915_deps;
struct i915_request;
struct i915_gem_ww_ctx;
struct intel_gt;
@@ -23,7 +24,7 @@ struct intel_context *intel_migrate_create_context(struct intel_migrate *m);
int intel_migrate_copy(struct intel_migrate *m,
struct i915_gem_ww_ctx *ww,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *src,
enum i915_cache_level src_cache_level,
bool src_is_lmem,
@@ -33,7 +34,7 @@ int intel_migrate_copy(struct intel_migrate *m,
struct i915_request **out);
int intel_context_migrate_copy(struct intel_context *ce,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *src,
enum i915_cache_level src_cache_level,
bool src_is_lmem,
@@ -45,7 +46,7 @@ int intel_context_migrate_copy(struct intel_context *ce,
int
intel_migrate_clear(struct intel_migrate *m,
struct i915_gem_ww_ctx *ww,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *sg,
enum i915_cache_level cache_level,
bool is_lmem,
@@ -53,7 +54,7 @@ intel_migrate_clear(struct intel_migrate *m,
struct i915_request **out);
int
intel_context_migrate_clear(struct intel_context *ce,
- struct dma_fence *await,
+ const struct i915_deps *deps,
struct scatterlist *sg,
enum i915_cache_level cache_level,
bool is_lmem,
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 40cf8ec0b9fc..7d804df27546 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -32,6 +32,7 @@
#include <linux/sched/mm.h>
#include "gem/i915_gem_context.h"
+#include "gem/i915_gem_ttm_move.h"
#include "gt/intel_breadcrumbs.h"
#include "gt/intel_context.h"
#include "gt/intel_engine.h"
@@ -1543,6 +1544,27 @@ i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence)
return 0;
}
+/**
+ * i915_request_await_deps - set this request to (async) wait upon a struct
+ * i915_deps dma_fence collection
+ * @rq: request we are wishing to use
+ * @deps: The struct i915_deps containing the dependencies.
+ *
+ * Returns 0 if successful, negative error code on error.
+ */
+int i915_request_await_deps(struct i915_request *rq, const struct i915_deps *deps)
+{
+ int i, err;
+
+ for (i = 0; i < deps->num_deps; ++i) {
+ err = i915_request_await_dma_fence(rq, deps->fences[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
/**
* i915_request_await_object - set this request to (async) wait upon a bo
* @to: request we are wishing to use
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index ce7714210697..170ee78c2858 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -47,6 +47,7 @@
struct drm_file;
struct drm_i915_gem_object;
struct drm_printer;
+struct i915_deps;
struct i915_request;
#if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
@@ -411,6 +412,7 @@ int i915_request_await_object(struct i915_request *to,
bool write);
int i915_request_await_dma_fence(struct i915_request *rq,
struct dma_fence *fence);
+int i915_request_await_deps(struct i915_request *rq, const struct i915_deps *deps);
int i915_request_await_execution(struct i915_request *rq,
struct dma_fence *fence);
--
2.31.1
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