![Sushmita Susheelendra](/assets/img/avatar_default.png)
Buffer object specific resources like pages, domains, sg list need not be protected with struct_mutex. They can be protected with a buffer object level lock. This simplifies locking and makes it easier to avoid potential recursive locking scenarios for SVM involving mmap_sem and struct_mutex. This also removes unnecessary serialization when creating buffer objects, and also between buffer object creation and GPU command submission. Signed-off-by: Sushmita Susheelendra <ssusheel@codeaurora.org> [robclark: squash in handling new locking for shrinker] Signed-off-by: Rob Clark <robdclark@gmail.com>
175 lines
4.6 KiB
C
175 lines
4.6 KiB
C
/*
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* Copyright (C) 2016 Red Hat
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* Author: Rob Clark <robdclark@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "msm_drv.h"
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#include "msm_gem.h"
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static bool msm_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
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{
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/* NOTE: we are *closer* to being able to get rid of
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* mutex_trylock_recursive().. the msm_gem code itself does
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* not need struct_mutex, although codepaths that can trigger
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* shrinker are still called in code-paths that hold the
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* struct_mutex.
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*
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* Also, msm_obj->madv is protected by struct_mutex.
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*
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* The next step is probably split out a seperate lock for
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* protecting inactive_list, so that shrinker does not need
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* struct_mutex.
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*/
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switch (mutex_trylock_recursive(&dev->struct_mutex)) {
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case MUTEX_TRYLOCK_FAILED:
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return false;
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case MUTEX_TRYLOCK_SUCCESS:
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*unlock = true;
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return true;
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case MUTEX_TRYLOCK_RECURSIVE:
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*unlock = false;
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return true;
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}
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BUG();
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}
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static unsigned long
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msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct msm_drm_private *priv =
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container_of(shrinker, struct msm_drm_private, shrinker);
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struct drm_device *dev = priv->dev;
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struct msm_gem_object *msm_obj;
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unsigned long count = 0;
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bool unlock;
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if (!msm_gem_shrinker_lock(dev, &unlock))
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return 0;
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list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
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if (is_purgeable(msm_obj))
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count += msm_obj->base.size >> PAGE_SHIFT;
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}
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if (unlock)
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mutex_unlock(&dev->struct_mutex);
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return count;
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}
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static unsigned long
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msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct msm_drm_private *priv =
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container_of(shrinker, struct msm_drm_private, shrinker);
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struct drm_device *dev = priv->dev;
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struct msm_gem_object *msm_obj;
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unsigned long freed = 0;
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bool unlock;
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if (!msm_gem_shrinker_lock(dev, &unlock))
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return SHRINK_STOP;
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list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
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if (freed >= sc->nr_to_scan)
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break;
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if (is_purgeable(msm_obj)) {
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msm_gem_purge(&msm_obj->base, OBJ_LOCK_SHRINKER);
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freed += msm_obj->base.size >> PAGE_SHIFT;
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}
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}
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if (unlock)
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mutex_unlock(&dev->struct_mutex);
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if (freed > 0)
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pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
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return freed;
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}
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static int
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msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
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{
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struct msm_drm_private *priv =
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container_of(nb, struct msm_drm_private, vmap_notifier);
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struct drm_device *dev = priv->dev;
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struct msm_gem_object *msm_obj;
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unsigned unmapped = 0;
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bool unlock;
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if (!msm_gem_shrinker_lock(dev, &unlock))
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return NOTIFY_DONE;
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list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
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if (is_vunmapable(msm_obj)) {
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msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);
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/* since we don't know any better, lets bail after a few
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* and if necessary the shrinker will be invoked again.
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* Seems better than unmapping *everything*
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*/
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if (++unmapped >= 15)
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break;
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}
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}
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if (unlock)
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mutex_unlock(&dev->struct_mutex);
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*(unsigned long *)ptr += unmapped;
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if (unmapped > 0)
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pr_info_ratelimited("Purging %u vmaps\n", unmapped);
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return NOTIFY_DONE;
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}
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/**
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* msm_gem_shrinker_init - Initialize msm shrinker
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* @dev_priv: msm device
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*
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* This function registers and sets up the msm shrinker.
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*/
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void msm_gem_shrinker_init(struct drm_device *dev)
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{
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struct msm_drm_private *priv = dev->dev_private;
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priv->shrinker.count_objects = msm_gem_shrinker_count;
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priv->shrinker.scan_objects = msm_gem_shrinker_scan;
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priv->shrinker.seeks = DEFAULT_SEEKS;
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WARN_ON(register_shrinker(&priv->shrinker));
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priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
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WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
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}
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/**
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* msm_gem_shrinker_cleanup - Clean up msm shrinker
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* @dev_priv: msm device
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*
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* This function unregisters the msm shrinker.
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*/
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void msm_gem_shrinker_cleanup(struct drm_device *dev)
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{
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struct msm_drm_private *priv = dev->dev_private;
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if (priv->shrinker.nr_deferred) {
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WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
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unregister_shrinker(&priv->shrinker);
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}
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}
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