[PATCH 10/16] drm/i915/vm_bind: Abstract out common execbuf functions
Matthew Auld
matthew.auld at intel.com
Fri Sep 30 10:45:34 UTC 2022
On 28/09/2022 07:19, Niranjana Vishwanathapura wrote:
> The new execbuf3 ioctl path and the legacy execbuf ioctl
> paths have many common functionalities.
> Abstract out the common execbuf functionalities into a
> separate file where possible, thus allowing code sharing.
>
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
> ---
> drivers/gpu/drm/i915/Makefile | 1 +
> .../drm/i915/gem/i915_gem_execbuffer_common.c | 664 ++++++++++++++++++
> .../drm/i915/gem/i915_gem_execbuffer_common.h | 74 ++
> 3 files changed, 739 insertions(+)
> create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.c
> create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 9bf939ef18ea..bf952f478555 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -148,6 +148,7 @@ gem-y += \
> gem/i915_gem_create.o \
> gem/i915_gem_dmabuf.o \
> gem/i915_gem_domain.o \
> + gem/i915_gem_execbuffer_common.o \
> gem/i915_gem_execbuffer.o \
> gem/i915_gem_internal.o \
> gem/i915_gem_object.o \
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.c
> new file mode 100644
> index 000000000000..a7efd74afc9c
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer_common.c
> @@ -0,0 +1,664 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2022 Intel Corporation
> + */
> +
> +#include <linux/dma-fence-array.h>
> +
> +#include <drm/drm_syncobj.h>
> +
> +#include "gt/intel_context.h"
> +#include "gt/intel_gt.h"
> +#include "gt/intel_gt_pm.h"
> +#include "gt/intel_ring.h"
> +
> +#include "i915_gem_execbuffer_common.h"
> +
> +#define __EXEC_COMMON_FENCE_WAIT BIT(0)
> +#define __EXEC_COMMON_FENCE_SIGNAL BIT(1)
> +
> +static struct i915_request *eb_throttle(struct intel_context *ce)
> +{
> + struct intel_ring *ring = ce->ring;
> + struct intel_timeline *tl = ce->timeline;
> + struct i915_request *rq;
> +
> + /*
> + * Completely unscientific finger-in-the-air estimates for suitable
> + * maximum user request size (to avoid blocking) and then backoff.
> + */
> + if (intel_ring_update_space(ring) >= PAGE_SIZE)
> + return NULL;
> +
> + /*
> + * Find a request that after waiting upon, there will be at least half
> + * the ring available. The hysteresis allows us to compete for the
> + * shared ring and should mean that we sleep less often prior to
> + * claiming our resources, but not so long that the ring completely
> + * drains before we can submit our next request.
> + */
> + list_for_each_entry(rq, &tl->requests, link) {
> + if (rq->ring != ring)
> + continue;
> +
> + if (__intel_ring_space(rq->postfix,
> + ring->emit, ring->size) > ring->size / 2)
> + break;
> + }
> + if (&rq->link == &tl->requests)
> + return NULL; /* weird, we will check again later for real */
> +
> + return i915_request_get(rq);
> +}
> +
> +static int eb_pin_timeline(struct intel_context *ce, bool throttle,
> + bool nonblock)
> +{
> + struct intel_timeline *tl;
> + struct i915_request *rq = NULL;
> +
> + /*
> + * Take a local wakeref for preparing to dispatch the execbuf as
> + * we expect to access the hardware fairly frequently in the
> + * process, and require the engine to be kept awake between accesses.
> + * Upon dispatch, we acquire another prolonged wakeref that we hold
> + * until the timeline is idle, which in turn releases the wakeref
> + * taken on the engine, and the parent device.
> + */
> + tl = intel_context_timeline_lock(ce);
> + if (IS_ERR(tl))
> + return PTR_ERR(tl);
> +
> + intel_context_enter(ce);
> + if (throttle)
> + rq = eb_throttle(ce);
> + intel_context_timeline_unlock(tl);
> +
> + if (rq) {
> + long timeout = nonblock ? 0 : MAX_SCHEDULE_TIMEOUT;
> +
> + if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
> + timeout) < 0) {
> + i915_request_put(rq);
> +
> + /*
> + * Error path, cannot use intel_context_timeline_lock as
> + * that is user interruptable and this clean up step
> + * must be done.
> + */
> + mutex_lock(&ce->timeline->mutex);
> + intel_context_exit(ce);
> + mutex_unlock(&ce->timeline->mutex);
> +
> + if (nonblock)
> + return -EWOULDBLOCK;
> + else
> + return -EINTR;
> + }
> + i915_request_put(rq);
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * i915_eb_pin_engine() - Pin the engine
> + * @ce: the context
> + * @ww: optional locking context or NULL
> + * @throttle: throttle to ensure enough ring space
> + * @nonblock: do not block during throttle
> + *
> + * Pin the @ce timeline. If @throttle is set, enable throttling to ensure
> + * enough ring space is available either by waiting for requests to complete
> + * (if @nonblock is not set) or by returning error -EWOULDBLOCK (if @nonblock
> + * is set).
> + *
> + * Returns 0 upon success, -ve error code upon error.
> + */
> +int i915_eb_pin_engine(struct intel_context *ce, struct i915_gem_ww_ctx *ww,
> + bool throttle, bool nonblock)
> +{
> + struct intel_context *child;
> + int err;
> + int i = 0, j = 0;
> +
> + if (unlikely(intel_context_is_banned(ce)))
> + return -EIO;
> +
> + /*
> + * Pinning the contexts may generate requests in order to acquire
> + * GGTT space, so do this first before we reserve a seqno for
> + * ourselves.
> + */
> + err = intel_context_pin_ww(ce, ww);
> + if (err)
> + return err;
> +
> + for_each_child(ce, child) {
> + err = intel_context_pin_ww(child, ww);
> + GEM_BUG_ON(err); /* perma-pinned should incr a counter */
> + }
> +
> + for_each_child(ce, child) {
> + err = eb_pin_timeline(child, throttle, nonblock);
> + if (err)
> + goto unwind;
> + ++i;
> + }
> + err = eb_pin_timeline(ce, throttle, nonblock);
> + if (err)
> + goto unwind;
> +
> + return 0;
> +
> +unwind:
> + for_each_child(ce, child) {
> + if (j++ < i) {
> + mutex_lock(&child->timeline->mutex);
> + intel_context_exit(child);
> + mutex_unlock(&child->timeline->mutex);
> + }
> + }
> + for_each_child(ce, child)
> + intel_context_unpin(child);
> + intel_context_unpin(ce);
> + return err;
> +}
> +
> +/**
> + * i915_eb_unpin_engine() - Unpin the engine
> + * @ce: the context
> + *
> + * Unpin the @ce timeline.
> + */
> +void i915_eb_unpin_engine(struct intel_context *ce)
> +{
> + struct intel_context *child;
> +
> + for_each_child(ce, child) {
> + mutex_lock(&child->timeline->mutex);
> + intel_context_exit(child);
> + mutex_unlock(&child->timeline->mutex);
> +
> + intel_context_unpin(child);
> + }
> +
> + mutex_lock(&ce->timeline->mutex);
> + intel_context_exit(ce);
> + mutex_unlock(&ce->timeline->mutex);
> +
> + intel_context_unpin(ce);
> +}
> +
> +/**
> + * i915_eb_find_context() - Find the context
> + * @context: the context
> + * @context_number: required context index
> + *
> + * Returns the @context_number'th child of specified @context,
> + * or NULL if the child context is not found.
> + * If @context_number is 0, return the specified @context.
> + */
> +struct intel_context *
> +i915_eb_find_context(struct intel_context *context, unsigned int context_number)
> +{
> + struct intel_context *child;
> +
> + if (likely(context_number == 0))
> + return context;
> +
> + for_each_child(context, child)
> + if (!--context_number)
> + return child;
> +
> + GEM_BUG_ON("Context not found");
> +
> + return NULL;
> +}
> +
> +static void __free_fence_array(struct eb_fence *fences, u64 n)
> +{
> + while (n--) {
> + drm_syncobj_put(ptr_mask_bits(fences[n].syncobj, 2));
> + dma_fence_put(fences[n].dma_fence);
> + dma_fence_chain_free(fences[n].chain_fence);
> + }
> + kvfree(fences);
> +}
> +
> +/**
> + * i915_eb_put_fence_array() - Free Execbuffer fence array
> + * @fences: Pointer to array of Execbuffer fences (See struct eb_fences)
> + * @num_fences: Number of fences in @fences array
> + *
> + * Free the Execbuffer fences in @fences array.
> + */
> +void i915_eb_put_fence_array(struct eb_fence *fences, u64 num_fences)
> +{
> + if (fences)
> + __free_fence_array(fences, num_fences);
> +}
> +
> +/**
> + * i915_eb_add_timeline_fence() - Add a fence to the specified Execbuffer fence
> + * array.
> + * @file: drm file pointer
> + * @handle: drm_syncobj handle
> + * @point: point in the timeline
> + * @f: Execbuffer fence
> + * @wait: wait for the specified fence
> + * @signal: signal the specified fence
> + *
> + * Add the fence specified by drm_syncobj @handle at specified @point in the
> + * timeline to the Execbuffer fence array @f. If @wait is specified, it is an
> + * input fence and if @signal is specified it is an output fence.
> + *
> + * Returns 0 upon success, -ve error upon failure.
Also can return 1, which also means success. Also maybe clarify that
zero here is special.
Acked-by: Matthew Auld <matthew.auld at intel.com>
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