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55b9a0549e
Lockdep reports a circular locking dependency with pages_lock taken in the shrinker callback. The deadlock can't actually happen with current users at least as a BO will never be purgeable when pages_lock is held. To be safe, let's use mutex_trylock() instead and bail if a BO is locked already. Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-by: Steven Price <steven.price@arm.com> Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190823021216.5862-7-robh@kernel.org
111 lines
2.7 KiB
C
111 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (C) 2019 Arm Ltd.
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*
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* Based on msm_gem_freedreno.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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#include <linux/list.h>
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#include <drm/drm_device.h>
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#include <drm/drm_gem_shmem_helper.h>
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#include "panfrost_device.h"
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#include "panfrost_gem.h"
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#include "panfrost_mmu.h"
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static unsigned long
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panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct panfrost_device *pfdev =
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container_of(shrinker, struct panfrost_device, shrinker);
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struct drm_gem_shmem_object *shmem;
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unsigned long count = 0;
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if (!mutex_trylock(&pfdev->shrinker_lock))
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return 0;
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list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
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if (drm_gem_shmem_is_purgeable(shmem))
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count += shmem->base.size >> PAGE_SHIFT;
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}
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mutex_unlock(&pfdev->shrinker_lock);
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return count;
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}
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static bool panfrost_gem_purge(struct drm_gem_object *obj)
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{
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struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
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if (!mutex_trylock(&shmem->pages_lock))
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return false;
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panfrost_mmu_unmap(to_panfrost_bo(obj));
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drm_gem_shmem_purge_locked(obj);
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mutex_unlock(&shmem->pages_lock);
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return true;
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}
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static unsigned long
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panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct panfrost_device *pfdev =
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container_of(shrinker, struct panfrost_device, shrinker);
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struct drm_gem_shmem_object *shmem, *tmp;
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unsigned long freed = 0;
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if (!mutex_trylock(&pfdev->shrinker_lock))
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return SHRINK_STOP;
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list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
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if (freed >= sc->nr_to_scan)
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break;
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if (drm_gem_shmem_is_purgeable(shmem) &&
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panfrost_gem_purge(&shmem->base)) {
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freed += shmem->base.size >> PAGE_SHIFT;
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list_del_init(&shmem->madv_list);
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}
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}
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mutex_unlock(&pfdev->shrinker_lock);
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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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/**
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* panfrost_gem_shrinker_init - Initialize panfrost shrinker
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* @dev: DRM device
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*
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* This function registers and sets up the panfrost shrinker.
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*/
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void panfrost_gem_shrinker_init(struct drm_device *dev)
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{
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struct panfrost_device *pfdev = dev->dev_private;
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pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
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pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
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pfdev->shrinker.seeks = DEFAULT_SEEKS;
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WARN_ON(register_shrinker(&pfdev->shrinker));
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}
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/**
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* panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
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* @dev: DRM device
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*
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* This function unregisters the panfrost shrinker.
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*/
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void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
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{
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struct panfrost_device *pfdev = dev->dev_private;
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if (pfdev->shrinker.nr_deferred) {
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unregister_shrinker(&pfdev->shrinker);
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}
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}
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