In the coming patches, we will share the lru list b/t ttm bo based memory allocator and hmm/svm based memory allocator. Thus lru_lock (which is used mainly to protect the lru list) is moved from struct ttm_device to struct drm_device, so this lock can be shared b/t those two memory allocators. To minimize code change, struct ttm_device still hold a weak reference of lru_lock, so ttm layer can still reference to this lock easily. Signed-off-by: Oak Zeng <oak.zeng@xxxxxxxxx> --- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 +- drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 4 +- drivers/gpu/drm/drm_drv.c | 1 + drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 4 +- drivers/gpu/drm/ttm/ttm_bo.c | 40 +++++++++---------- drivers/gpu/drm/ttm/ttm_device.c | 18 ++++----- drivers/gpu/drm/ttm/ttm_resource.c | 42 ++++++++++---------- drivers/gpu/drm/xe/xe_bo.c | 4 +- drivers/gpu/drm/xe/xe_exec.c | 4 +- drivers/gpu/drm/xe/xe_vm.c | 4 +- include/drm/drm_device.h | 5 +++ include/drm/ttm/ttm_bo.h | 4 +- include/drm/ttm/ttm_device.h | 4 +- 13 files changed, 72 insertions(+), 66 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index f5daadcec865..747bcad86d5d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -368,9 +368,9 @@ int amdgpu_vm_lock_pd(struct amdgpu_vm *vm, struct drm_exec *exec, void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev, struct amdgpu_vm *vm) { - spin_lock(&adev->mman.bdev.lru_lock); + spin_lock(adev->mman.bdev.lru_lock); ttm_lru_bulk_move_tail(&vm->lru_bulk_move); - spin_unlock(&adev->mman.bdev.lru_lock); + spin_unlock(adev->mman.bdev.lru_lock); } /* Create scheduler entities for page table updates */ diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c index c7085a747b03..b83e1741905e 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c @@ -290,9 +290,9 @@ static void amdgpu_vram_mgr_do_reserve(struct ttm_resource_manager *man) vis_usage = amdgpu_vram_mgr_vis_size(adev, block); atomic64_add(vis_usage, &mgr->vis_usage); - spin_lock(&man->bdev->lru_lock); + spin_lock(man->bdev->lru_lock); man->usage += rsv->size; - spin_unlock(&man->bdev->lru_lock); + spin_unlock(man->bdev->lru_lock); list_move(&rsv->blocks, &mgr->reserved_pages); } } diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 3eda026ffac6..1943c38815aa 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -623,6 +623,7 @@ static int drm_dev_init(struct drm_device *dev, INIT_LIST_HEAD(&dev->managed.resources); spin_lock_init(&dev->managed.lock); + spin_lock_init(&dev->lru_lock); /* no per-device feature limits by default */ dev->driver_features = ~0u; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c index 9227f8146a58..c46f54f83f54 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c @@ -984,7 +984,7 @@ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj) /* * Put on the correct LRU list depending on the MADV status */ - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); if (shrinkable) { /* Try to keep shmem_tt from being considered for shrinking. */ bo->priority = TTM_MAX_BO_PRIORITY - 1; @@ -1013,7 +1013,7 @@ void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj) } ttm_bo_move_to_lru_tail(bo); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } /* diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index e58b7e249816..26e0555bad0c 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -68,7 +68,7 @@ static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo, * @bo: The buffer object. * * Move this BO to the tail of all lru lists used to lookup and reserve an - * object. This function must be called with struct ttm_global::lru_lock + * object. This function must be called with struct drm_device::lru_lock * held, and is used to make a BO less likely to be considered for eviction. */ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo) @@ -102,13 +102,13 @@ void ttm_bo_set_bulk_move(struct ttm_buffer_object *bo, if (bo->bulk_move == bulk) return; - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); if (bo->resource) ttm_resource_del_bulk_move(bo->resource, bo); bo->bulk_move = bulk; if (bo->resource) ttm_resource_add_bulk_move(bo->resource, bo); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } EXPORT_SYMBOL(ttm_bo_set_bulk_move); @@ -202,9 +202,9 @@ static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo) * reference it any more. The only tricky case is the trylock on * the resv object while holding the lru_lock. */ - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); bo->base.resv = &bo->base._resv; - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } return r; @@ -255,7 +255,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, if (unlock_resv) dma_resv_unlock(bo->base.resv); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); lret = dma_resv_wait_timeout(resv, DMA_RESV_USAGE_BOOKKEEP, interruptible, @@ -266,7 +266,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, else if (lret == 0) return -EBUSY; - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); if (unlock_resv && !dma_resv_trylock(bo->base.resv)) { /* * We raced, and lost, someone else holds the reservation now, @@ -276,7 +276,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, * delayed destruction would succeed, so just return success * here. */ - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); return 0; } ret = 0; @@ -285,11 +285,11 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, if (ret) { if (unlock_resv) dma_resv_unlock(bo->base.resv); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); return ret; } - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); ttm_bo_cleanup_memtype_use(bo); if (unlock_resv) @@ -351,7 +351,7 @@ static void ttm_bo_release(struct kref *kref) ttm_bo_flush_all_fences(bo); bo->deleted = true; - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); /* * Make pinned bos immediately available to @@ -367,7 +367,7 @@ static void ttm_bo_release(struct kref *kref) } kref_init(&bo->kref); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); INIT_WORK(&bo->delayed_delete, ttm_bo_delayed_delete); queue_work(bdev->wq, &bo->delayed_delete); @@ -598,7 +598,7 @@ int ttm_mem_evict_first(struct ttm_device *bdev, bool locked = false; int ret; - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); ttm_resource_manager_for_each_res(man, &cursor, res) { bool busy; @@ -621,7 +621,7 @@ int ttm_mem_evict_first(struct ttm_device *bdev, if (!bo) { if (busy_bo && !ttm_bo_get_unless_zero(busy_bo)) busy_bo = NULL; - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); ret = ttm_mem_evict_wait_busy(busy_bo, ctx, ticket); if (busy_bo) ttm_bo_put(busy_bo); @@ -635,7 +635,7 @@ int ttm_mem_evict_first(struct ttm_device *bdev, return ret; } - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); ret = ttm_bo_evict(bo, ctx); if (locked) @@ -658,11 +658,11 @@ void ttm_bo_pin(struct ttm_buffer_object *bo) { dma_resv_assert_held(bo->base.resv); WARN_ON_ONCE(!kref_read(&bo->kref)); - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); if (bo->resource) ttm_resource_del_bulk_move(bo->resource, bo); ++bo->pin_count; - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } EXPORT_SYMBOL(ttm_bo_pin); @@ -679,11 +679,11 @@ void ttm_bo_unpin(struct ttm_buffer_object *bo) if (WARN_ON_ONCE(!bo->pin_count)) return; - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); --bo->pin_count; if (bo->resource) ttm_resource_add_bulk_move(bo->resource, bo); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } EXPORT_SYMBOL(ttm_bo_unpin); @@ -1156,7 +1156,7 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx, } /* TODO: Cleanup the locking */ - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); /* * Move to system cached diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c index 12014788b595..d18eca86ebd6 100644 --- a/drivers/gpu/drm/ttm/ttm_device.c +++ b/drivers/gpu/drm/ttm/ttm_device.c @@ -147,7 +147,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx, unsigned i; int ret; - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) { man = ttm_manager_type(bdev, i); if (!man || !man->use_tt) @@ -169,7 +169,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx, return ret; } } - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); return 0; } EXPORT_SYMBOL(ttm_device_swapout); @@ -217,7 +217,7 @@ int ttm_device_init(struct ttm_device *bdev, const struct ttm_device_funcs *func use_dma_alloc, use_dma32); bdev->vma_manager = vma_manager; - spin_lock_init(&bdev->lru_lock); + bdev->lru_lock = &drm->lru_lock; INIT_LIST_HEAD(&bdev->pinned); bdev->dev_mapping = mapping; mutex_lock(&ttm_global_mutex); @@ -244,11 +244,11 @@ void ttm_device_fini(struct ttm_device *bdev) drain_workqueue(bdev->wq); destroy_workqueue(bdev->wq); - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) if (list_empty(&man->lru[0])) pr_debug("Swap list %d was clean\n", i); - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); ttm_pool_fini(&bdev->pool); ttm_global_release(); @@ -260,7 +260,7 @@ static void ttm_device_clear_lru_dma_mappings(struct ttm_device *bdev, { struct ttm_resource *res; - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); while ((res = list_first_entry_or_null(list, typeof(*res), lru))) { struct ttm_buffer_object *bo = res->bo; @@ -269,15 +269,15 @@ static void ttm_device_clear_lru_dma_mappings(struct ttm_device *bdev, continue; list_del_init(&res->lru); - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); if (bo->ttm) ttm_tt_unpopulate(bo->bdev, bo->ttm); ttm_bo_put(bo); - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); } - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); } void ttm_device_clear_dma_mappings(struct ttm_device *bdev) diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c index 46ff9c75bb12..6ada77f51fba 100644 --- a/drivers/gpu/drm/ttm/ttm_resource.c +++ b/drivers/gpu/drm/ttm/ttm_resource.c @@ -48,7 +48,7 @@ EXPORT_SYMBOL(ttm_lru_bulk_move_init); * @bulk: bulk move structure * * Bulk move BOs to the LRU tail, only valid to use when driver makes sure that - * resource order never changes. Should be called with &ttm_device.lru_lock held. + * resource order never changes. Should be called with &drm_device.lru_lock held. */ void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk) { @@ -62,7 +62,7 @@ void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk) if (!pos->first) continue; - lockdep_assert_held(&pos->first->bo->bdev->lru_lock); + lockdep_assert_held(pos->first->bo->bdev->lru_lock); dma_resv_assert_held(pos->first->bo->base.resv); dma_resv_assert_held(pos->last->bo->base.resv); @@ -148,7 +148,7 @@ void ttm_resource_move_to_lru_tail(struct ttm_resource *res) struct ttm_buffer_object *bo = res->bo; struct ttm_device *bdev = bo->bdev; - lockdep_assert_held(&bo->bdev->lru_lock); + lockdep_assert_held(bo->bdev->lru_lock); if (bo->pin_count) { list_move_tail(&res->lru, &bdev->pinned); @@ -191,13 +191,13 @@ void ttm_resource_init(struct ttm_buffer_object *bo, res->bo = bo; man = ttm_manager_type(bo->bdev, place->mem_type); - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); if (bo->pin_count) list_add_tail(&res->lru, &bo->bdev->pinned); else list_add_tail(&res->lru, &man->lru[bo->priority]); man->usage += res->size; - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } EXPORT_SYMBOL(ttm_resource_init); @@ -216,10 +216,10 @@ void ttm_resource_fini(struct ttm_resource_manager *man, { struct ttm_device *bdev = man->bdev; - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); list_del_init(&res->lru); man->usage -= res->size; - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); } EXPORT_SYMBOL(ttm_resource_fini); @@ -235,9 +235,9 @@ int ttm_resource_alloc(struct ttm_buffer_object *bo, if (ret) return ret; - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); ttm_resource_add_bulk_move(*res_ptr, bo); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); return 0; } @@ -248,9 +248,9 @@ void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource **res) if (!*res) return; - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); ttm_resource_del_bulk_move(*res, bo); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); man = ttm_manager_type(bo->bdev, (*res)->mem_type); man->func->free(man, *res); *res = NULL; @@ -368,9 +368,9 @@ bool ttm_resource_compat(struct ttm_resource *res, void ttm_resource_set_bo(struct ttm_resource *res, struct ttm_buffer_object *bo) { - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); res->bo = bo; - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } /** @@ -424,18 +424,18 @@ int ttm_resource_manager_evict_all(struct ttm_device *bdev, * Can't use standard list traversal since we're unlocking. */ - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { while (!list_empty(&man->lru[i])) { - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); ret = ttm_mem_evict_first(bdev, man, NULL, &ctx, NULL); if (ret) return ret; - spin_lock(&bdev->lru_lock); + spin_lock(bdev->lru_lock); } } - spin_unlock(&bdev->lru_lock); + spin_unlock(bdev->lru_lock); spin_lock(&man->move_lock); fence = dma_fence_get(man->move); @@ -463,9 +463,9 @@ uint64_t ttm_resource_manager_usage(struct ttm_resource_manager *man) { uint64_t usage; - spin_lock(&man->bdev->lru_lock); + spin_lock(man->bdev->lru_lock); usage = man->usage; - spin_unlock(&man->bdev->lru_lock); + spin_unlock(man->bdev->lru_lock); return usage; } EXPORT_SYMBOL(ttm_resource_manager_usage); @@ -502,7 +502,7 @@ ttm_resource_manager_first(struct ttm_resource_manager *man, { struct ttm_resource *res; - lockdep_assert_held(&man->bdev->lru_lock); + lockdep_assert_held(man->bdev->lru_lock); for (cursor->priority = 0; cursor->priority < TTM_MAX_BO_PRIORITY; ++cursor->priority) @@ -526,7 +526,7 @@ ttm_resource_manager_next(struct ttm_resource_manager *man, struct ttm_resource_cursor *cursor, struct ttm_resource *res) { - lockdep_assert_held(&man->bdev->lru_lock); + lockdep_assert_held(man->bdev->lru_lock); list_for_each_entry_continue(res, &man->lru[cursor->priority], lru) return res; diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c index 25fdc04627ca..827f798cccc0 100644 --- a/drivers/gpu/drm/xe/xe_bo.c +++ b/drivers/gpu/drm/xe/xe_bo.c @@ -946,9 +946,9 @@ static bool xe_ttm_bo_lock_in_destructor(struct ttm_buffer_object *ttm_bo) * the ttm_bo refcount is zero at this point. So trylocking *should* * always succeed here, as long as we hold the lru lock. */ - spin_lock(&ttm_bo->bdev->lru_lock); + spin_lock(ttm_bo->bdev->lru_lock); locked = dma_resv_trylock(ttm_bo->base.resv); - spin_unlock(&ttm_bo->bdev->lru_lock); + spin_unlock(ttm_bo->bdev->lru_lock); XE_WARN_ON(!locked); return locked; diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c index 890fadb0a93e..dafebdfb2368 100644 --- a/drivers/gpu/drm/xe/xe_exec.c +++ b/drivers/gpu/drm/xe/xe_exec.c @@ -370,9 +370,9 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file) xe_vm_reactivate_rebind(vm); if (!err && !xe_vm_no_dma_fences(vm)) { - spin_lock(&xe->ttm.lru_lock); + spin_lock(xe->ttm.lru_lock); ttm_lru_bulk_move_tail(&vm->lru_bulk_move); - spin_unlock(&xe->ttm.lru_lock); + spin_unlock(xe->ttm.lru_lock); } err_repin: diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index a6a0f17fec1d..44e038276d41 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -651,9 +651,9 @@ static void preempt_rebind_work_func(struct work_struct *w) #undef retry_required - spin_lock(&vm->xe->ttm.lru_lock); + spin_lock(vm->xe->ttm.lru_lock); ttm_lru_bulk_move_tail(&vm->lru_bulk_move); - spin_unlock(&vm->xe->ttm.lru_lock); + spin_unlock(vm->xe->ttm.lru_lock); /* Point of no return. */ arm_preempt_fences(vm, &preempt_fences); diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index 7cf4afae2e79..d0b5f42786be 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -326,6 +326,11 @@ struct drm_device { */ struct list_head debugfs_list; + /** + * @lru_lock: Protection for the per manager LRU and destroy lists. + */ + spinlock_t lru_lock; + /* Everything below here is for legacy driver, never use! */ /* private: */ #if IS_ENABLED(CONFIG_DRM_LEGACY) diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h index 0223a41a64b2..49f32df32204 100644 --- a/include/drm/ttm/ttm_bo.h +++ b/include/drm/ttm/ttm_bo.h @@ -290,9 +290,9 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo); static inline void ttm_bo_move_to_lru_tail_unlocked(struct ttm_buffer_object *bo) { - spin_lock(&bo->bdev->lru_lock); + spin_lock(bo->bdev->lru_lock); ttm_bo_move_to_lru_tail(bo); - spin_unlock(&bo->bdev->lru_lock); + spin_unlock(bo->bdev->lru_lock); } static inline void ttm_bo_assign_mem(struct ttm_buffer_object *bo, diff --git a/include/drm/ttm/ttm_device.h b/include/drm/ttm/ttm_device.h index bab868d55383..4d29e96bd892 100644 --- a/include/drm/ttm/ttm_device.h +++ b/include/drm/ttm/ttm_device.h @@ -248,9 +248,9 @@ struct ttm_device { struct ttm_pool pool; /** - * @lru_lock: Protection for the per manager LRU and ddestroy lists. + * @lru_lock: Weak reference to drm_device::lru_lock. */ - spinlock_t lru_lock; + spinlock_t *lru_lock; /** * @pinned: Buffer objects which are pinned and so not on any LRU list. -- 2.26.3