i915_gem_evict.c

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/*
 * Copyright © 2008-2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eric Anholt <[email protected]>
 *    Chris Wilson <[email protected]>
 *
 */

#include <drm/drmP.h>
#include "i915_drv.h"
#include <drm/i915_drm.h>
#include "i915_trace.h"

static bool
mark_free(struct drm_i915_gem_object *obj, struct list_head *unwind)
{
    if (obj->pin_count)
        return false;

    list_add(&obj->exec_list, unwind);
    return drm_mm_scan_add_block(obj->gtt_space);
}

int
i915_gem_evict_something(struct drm_device *dev, int min_size,
             unsigned alignment, unsigned cache_level,
             bool mappable, bool nonblocking)
{
    drm_i915_private_t *dev_priv = dev->dev_private;
    struct list_head eviction_list, unwind_list;
    struct drm_i915_gem_object *obj;
    int ret = 0;

    trace_i915_gem_evict(dev, min_size, alignment, mappable);

    /*
     * The goal is to evict objects and amalgamate space in LRU order.
     * The oldest idle objects reside on the inactive list, which is in
     * retirement order. The next objects to retire are those on the (per
     * ring) active list that do not have an outstanding flush. Once the
     * hardware reports completion (the seqno is updated after the
     * batchbuffer has been finished) the clean buffer objects would
     * be retired to the inactive list. Any dirty objects would be added
     * to the tail of the flushing list. So after processing the clean
     * active objects we need to emit a MI_FLUSH to retire the flushing
     * list, hence the retirement order of the flushing list is in
     * advance of the dirty objects on the active lists.
     *
     * The retirement sequence is thus:
     *   1. Inactive objects (already retired)
     *   2. Clean active objects
     *   3. Flushing list
     *   4. Dirty active objects.
     *
     * On each list, the oldest objects lie at the HEAD with the freshest
     * object on the TAIL.
     */

    INIT_LIST_HEAD(&unwind_list);
    if (mappable)
        drm_mm_init_scan_with_range(&dev_priv->mm.gtt_space,
                        min_size, alignment, cache_level,
                        0, dev_priv->mm.gtt_mappable_end);
    else
        drm_mm_init_scan(&dev_priv->mm.gtt_space,
                 min_size, alignment, cache_level);

    /* First see if there is a large enough contiguous idle region... */
    list_for_each_entry(obj, &dev_priv->mm.inactive_list, mm_list) {
        if (mark_free(obj, &unwind_list))
            goto found;
    }

    if (nonblocking)
        goto none;

    /* Now merge in the soon-to-be-expired objects... */
    list_for_each_entry(obj, &dev_priv->mm.active_list, mm_list) {
        if (mark_free(obj, &unwind_list))
            goto found;
    }

none:
    /* Nothing found, clean up and bail out! */
    while (!list_empty(&unwind_list)) {
        obj = list_first_entry(&unwind_list,
                       struct drm_i915_gem_object,
                       exec_list);

        ret = drm_mm_scan_remove_block(obj->gtt_space);
        BUG_ON(ret);

        list_del_init(&obj->exec_list);
    }

    /* We expect the caller to unpin, evict all and try again, or give up.
     * So calling i915_gem_evict_everything() is unnecessary.
     */
    return -ENOSPC;

found:
    /* drm_mm doesn't allow any other other operations while
     * scanning, therefore store to be evicted objects on a
     * temporary list. */
    INIT_LIST_HEAD(&eviction_list);
    while (!list_empty(&unwind_list)) {
        obj = list_first_entry(&unwind_list,
                       struct drm_i915_gem_object,
                       exec_list);
        if (drm_mm_scan_remove_block(obj->gtt_space)) {
            list_move(&obj->exec_list, &eviction_list);
            drm_gem_object_reference(&obj->base);
            continue;
        }
        list_del_init(&obj->exec_list);
    }

    /* Unbinding will emit any required flushes */
    while (!list_empty(&eviction_list)) {
        obj = list_first_entry(&eviction_list,
                       struct drm_i915_gem_object,
                       exec_list);
        if (ret == 0)
            ret = i915_gem_object_unbind(obj);

        list_del_init(&obj->exec_list);
        drm_gem_object_unreference(&obj->base);
    }

    return ret;
}

int
i915_gem_evict_everything(struct drm_device *dev)
{
    drm_i915_private_t *dev_priv = dev->dev_private;
    struct drm_i915_gem_object *obj, *next;
    bool lists_empty;
    int ret;

    lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
               list_empty(&dev_priv->mm.active_list));
    if (lists_empty)
        return -ENOSPC;

    trace_i915_gem_evict_everything(dev);

    /* The gpu_idle will flush everything in the write domain to the
     * active list. Then we must move everything off the active list
     * with retire requests.
     */
    ret = i915_gpu_idle(dev);
    if (ret)
        return ret;

    i915_gem_retire_requests(dev);

    /* Having flushed everything, unbind() should never raise an error */
    list_for_each_entry_safe(obj, next,
                 &dev_priv->mm.inactive_list, mm_list)
        if (obj->pin_count == 0)
            WARN_ON(i915_gem_object_unbind(obj));

    return 0;
}