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![Chris Wilson](/assets/img/avatar_default.png)
In preparation to support many distinct timelines, we need to expand the activity tracking on the GEM object to handle more than just a request per engine. We already use the struct reservation_object on the dma-buf to handle many fence contexts, so integrating that into the GEM object itself is the preferred solution. (For example, we can now share the same reservation_object between every consumer/producer using this buffer and skip the manual import/export via dma-buf.) v2: Reimplement busy-ioctl (by walking the reservation object), postpone the ABI change for another day. Similarly use the reservation object to find the last_write request (if active and from i915) for choosing display CS flips. Caveats: * busy-ioctl: busy-ioctl only reports on the native fences, it will not warn of stalls (in set-domain-ioctl, pread/pwrite etc) if the object is being rendered to by external fences. It also will not report the same busy state as wait-ioctl (or polling on the dma-buf) in the same circumstances. On the plus side, it does retain reporting of which *i915* engines are engaged with this object. * non-blocking atomic modesets take a step backwards as the wait for render completion blocks the ioctl. This is fixed in a subsequent patch to use a fence instead for awaiting on the rendering, see "drm/i915: Restore nonblocking awaits for modesetting" * dynamic array manipulation for shared-fences in reservation is slower than the previous lockless static assignment (e.g. gem_exec_lut_handle runtime on ivb goes from 42s to 66s), mainly due to atomic operations (maintaining the fence refcounts). * loss of object-level retirement callbacks, emulated by VMA retirement tracking. * minor loss of object-level last activity information from debugfs, could be replaced with per-vma information if desired Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-21-chris@chris-wilson.co.uk
146 lines
4.4 KiB
C
146 lines
4.4 KiB
C
/*
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* Copyright © 2014 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include "i915_drv.h"
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#include "i915_gem_batch_pool.h"
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/**
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* DOC: batch pool
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*
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* In order to submit batch buffers as 'secure', the software command parser
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* must ensure that a batch buffer cannot be modified after parsing. It does
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* this by copying the user provided batch buffer contents to a kernel owned
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* buffer from which the hardware will actually execute, and by carefully
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* managing the address space bindings for such buffers.
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*
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* The batch pool framework provides a mechanism for the driver to manage a
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* set of scratch buffers to use for this purpose. The framework can be
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* extended to support other uses cases should they arise.
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*/
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/**
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* i915_gem_batch_pool_init() - initialize a batch buffer pool
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* @engine: the associated request submission engine
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* @pool: the batch buffer pool
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*/
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void i915_gem_batch_pool_init(struct intel_engine_cs *engine,
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struct i915_gem_batch_pool *pool)
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{
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int n;
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pool->engine = engine;
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for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
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INIT_LIST_HEAD(&pool->cache_list[n]);
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}
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/**
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* i915_gem_batch_pool_fini() - clean up a batch buffer pool
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* @pool: the pool to clean up
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*
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* Note: Callers must hold the struct_mutex.
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*/
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void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool)
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{
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int n;
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lockdep_assert_held(&pool->engine->i915->drm.struct_mutex);
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for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
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struct drm_i915_gem_object *obj, *next;
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list_for_each_entry_safe(obj, next,
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&pool->cache_list[n],
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batch_pool_link)
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__i915_gem_object_release_unless_active(obj);
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INIT_LIST_HEAD(&pool->cache_list[n]);
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}
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}
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/**
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* i915_gem_batch_pool_get() - allocate a buffer from the pool
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* @pool: the batch buffer pool
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* @size: the minimum desired size of the returned buffer
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*
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* Returns an inactive buffer from @pool with at least @size bytes,
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* with the pages pinned. The caller must i915_gem_object_unpin_pages()
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* on the returned object.
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*
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* Note: Callers must hold the struct_mutex
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*
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* Return: the buffer object or an error pointer
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*/
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struct drm_i915_gem_object *
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i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
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size_t size)
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{
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struct drm_i915_gem_object *obj = NULL;
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struct drm_i915_gem_object *tmp;
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struct list_head *list;
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int n, ret;
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lockdep_assert_held(&pool->engine->i915->drm.struct_mutex);
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/* Compute a power-of-two bucket, but throw everything greater than
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* 16KiB into the same bucket: i.e. the the buckets hold objects of
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* (1 page, 2 pages, 4 pages, 8+ pages).
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*/
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n = fls(size >> PAGE_SHIFT) - 1;
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if (n >= ARRAY_SIZE(pool->cache_list))
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n = ARRAY_SIZE(pool->cache_list) - 1;
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list = &pool->cache_list[n];
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list_for_each_entry(tmp, list, batch_pool_link) {
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/* The batches are strictly LRU ordered */
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if (i915_gem_object_is_active(tmp))
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break;
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GEM_BUG_ON(!reservation_object_test_signaled_rcu(tmp->resv,
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true));
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if (tmp->base.size >= size) {
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/* Clear the set of shared fences early */
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ww_mutex_lock(&tmp->resv->lock, NULL);
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reservation_object_add_excl_fence(tmp->resv, NULL);
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ww_mutex_unlock(&tmp->resv->lock);
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obj = tmp;
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break;
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}
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}
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if (obj == NULL) {
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obj = i915_gem_object_create_internal(pool->engine->i915, size);
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if (IS_ERR(obj))
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return obj;
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}
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ret = i915_gem_object_pin_pages(obj);
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if (ret)
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return ERR_PTR(ret);
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list_move_tail(&obj->batch_pool_link, list);
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return obj;
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}
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