[PATCH 4/7] drm/ttm: move LRU walk defines into new internal header

Matthew Brost matthew.brost at intel.com
Thu Jul 11 16:00:05 UTC 2024


On Thu, Jul 11, 2024 at 02:01:00PM +0200, Christian König wrote:
> Am 10.07.24 um 20:19 schrieb Matthew Brost:
> > On Wed, Jul 10, 2024 at 02:42:58PM +0200, Christian König wrote:
> > > That is something drivers really shouldn't mess with.
> > > 
> > Thomas uses this in Xe to implement a shrinker [1]. Seems to need to
> > remain available for drivers.
> 
> No, that is exactly what I try to prevent with that.
> 
> This is an internally thing of TTM and drivers should never use it directly.
> 

Admittedly having fully gotten through Thomas's shrinker patches so I
can't reasonably defend how Thomas is using the LRU walker in the Xe
driver but I will say Thomas is generally correct wrt layering code.

I'd say since he for the next month, table this patch until he returns
and we can all discuss options.

Matt

> Regards,
> Christian.
> 
> > 
> > Matt
> > 
> > [1] https://patchwork.freedesktop.org/patch/602165/?series=131815&rev=6
> > 
> > > Signed-off-by: Christian König <christian.koenig at amd.com>
> > > ---
> > >   drivers/gpu/drm/ttm/ttm_bo.c      |  1 +
> > >   drivers/gpu/drm/ttm/ttm_bo_util.c |  2 +
> > >   drivers/gpu/drm/ttm/ttm_bo_util.h | 67 +++++++++++++++++++++++++++++++
> > >   include/drm/ttm/ttm_bo.h          | 35 ----------------
> > >   4 files changed, 70 insertions(+), 35 deletions(-)
> > >   create mode 100644 drivers/gpu/drm/ttm/ttm_bo_util.h
> > > 
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> > > index 0131ec802066..41bee8696e69 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > > @@ -45,6 +45,7 @@
> > >   #include <linux/dma-resv.h>
> > >   #include "ttm_module.h"
> > > +#include "ttm_bo_util.h"
> > >   static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo,
> > >   					struct ttm_placement *placement)
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > index 3c07f4712d5c..03e28e3d0d03 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > @@ -37,6 +37,8 @@
> > >   #include <drm/drm_cache.h>
> > > +#include "ttm_bo_util.h"
> > > +
> > >   struct ttm_transfer_obj {
> > >   	struct ttm_buffer_object base;
> > >   	struct ttm_buffer_object *bo;
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.h b/drivers/gpu/drm/ttm/ttm_bo_util.h
> > > new file mode 100644
> > > index 000000000000..c19b50809208
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.h
> > > @@ -0,0 +1,67 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> > > +/**************************************************************************
> > > + * Copyright 2024 Advanced Micro Devices, Inc.
> > > + *
> > > + * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
> > > + *
> > > + **************************************************************************/
> > > +#ifndef _TTM_BO_UTIL_H_
> > > +#define _TTM_BO_UTIL_H_
> > > +
> > > +struct ww_acquire_ctx;
> > > +
> > > +struct ttm_buffer_object;
> > > +struct ttm_operation_ctx;
> > > +struct ttm_lru_walk;
> > > +
> > > +/** struct ttm_lru_walk_ops - Operations for a LRU walk. */
> > > +struct ttm_lru_walk_ops {
> > > +	/**
> > > +	 * process_bo - Process this bo.
> > > +	 * @walk: struct ttm_lru_walk describing the walk.
> > > +	 * @bo: A locked and referenced buffer object.
> > > +	 *
> > > +	 * Return: Negative error code on error, User-defined positive value
> > > +	 * (typically, but not always, size of the processed bo) on success.
> > > +	 * On success, the returned values are summed by the walk and the
> > > +	 * walk exits when its target is met.
> > > +	 * 0 also indicates success, -EBUSY means this bo was skipped.
> > > +	 */
> > > +	s64 (*process_bo)(struct ttm_lru_walk *walk,
> > > +			  struct ttm_buffer_object *bo);
> > > +};
> > > +
> > > +/**
> > > + * struct ttm_lru_walk - Structure describing a LRU walk.
> > > + */
> > > +struct ttm_lru_walk {
> > > +	/** @ops: Pointer to the ops structure. */
> > > +	const struct ttm_lru_walk_ops *ops;
> > > +	/** @ctx: Pointer to the struct ttm_operation_ctx. */
> > > +	struct ttm_operation_ctx *ctx;
> > > +	/** @ticket: The struct ww_acquire_ctx if any. */
> > > +	struct ww_acquire_ctx *ticket;
> > > +	/** @tryock_only: Only use trylock for locking. */
> > > +	bool trylock_only;
> > > +};
> > > +
> > > +s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
> > > +			   struct ttm_resource_manager *man, s64 target);
> > > +
> > > +#endif
> > > diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
> > > index d1a732d56259..5f7c967222a2 100644
> > > --- a/include/drm/ttm/ttm_bo.h
> > > +++ b/include/drm/ttm/ttm_bo.h
> > > @@ -194,41 +194,6 @@ struct ttm_operation_ctx {
> > >   	uint64_t bytes_moved;
> > >   };
> > > -struct ttm_lru_walk;
> > > -
> > > -/** struct ttm_lru_walk_ops - Operations for a LRU walk. */
> > > -struct ttm_lru_walk_ops {
> > > -	/**
> > > -	 * process_bo - Process this bo.
> > > -	 * @walk: struct ttm_lru_walk describing the walk.
> > > -	 * @bo: A locked and referenced buffer object.
> > > -	 *
> > > -	 * Return: Negative error code on error, User-defined positive value
> > > -	 * (typically, but not always, size of the processed bo) on success.
> > > -	 * On success, the returned values are summed by the walk and the
> > > -	 * walk exits when its target is met.
> > > -	 * 0 also indicates success, -EBUSY means this bo was skipped.
> > > -	 */
> > > -	s64 (*process_bo)(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo);
> > > -};
> > > -
> > > -/**
> > > - * struct ttm_lru_walk - Structure describing a LRU walk.
> > > - */
> > > -struct ttm_lru_walk {
> > > -	/** @ops: Pointer to the ops structure. */
> > > -	const struct ttm_lru_walk_ops *ops;
> > > -	/** @ctx: Pointer to the struct ttm_operation_ctx. */
> > > -	struct ttm_operation_ctx *ctx;
> > > -	/** @ticket: The struct ww_acquire_ctx if any. */
> > > -	struct ww_acquire_ctx *ticket;
> > > -	/** @tryock_only: Only use trylock for locking. */
> > > -	bool trylock_only;
> > > -};
> > > -
> > > -s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
> > > -			   struct ttm_resource_manager *man, s64 target);
> > > -
> > >   /**
> > >    * ttm_bo_get - reference a struct ttm_buffer_object
> > >    *
> > > -- 
> > > 2.34.1
> > > 
> 


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