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From: Ben Widawsky <ben@bwidawsk.net>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 17/18] drm/i915: Use a slab for object allocation
Date: Mon, 5 Nov 2012 17:49:35 +0000	[thread overview]
Message-ID: <20121105174935.579306dc@bwidawsk.net> (raw)
In-Reply-To: <1350666204-8101-17-git-send-email-chris@chris-wilson.co.uk>

On Fri, 19 Oct 2012 18:03:23 +0100
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> The primary purpose of this was to debug some use-after-free memory
> corruption that was causing an OOPS inside drm/i915. As it turned out
> the corruption was being caused elsewhere and i915.ko as a major user of
> many objects was being hit hardest.
> 
> Indeed as we do frequent the generic kmalloc caches, dedicating one to
> ourselves (or at least naming one for us depending upon the core) aids
> debugging our own slab usage.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

So I previously acked this patch, but you dropped that, so now you get
more words.

Why not go all the way and move all allocations we do in i915 to this
slab (adding a flag with whether or not to zero the memory first)? While
I agree in terms of space, nothing takes up as much as objects, I think
it would be nice to do this so we can totally track what our driver is
doing. In fact I would suggest this is something which core drm should
provide to all of the drivers (we already use drm_alloc calls in some
places).

Anyway, it's still:
Acked-by: Ben Widawsky <ben@bwidawsk.net>

> ---
>  drivers/gpu/drm/i915/i915_dma.c        |    3 +++
>  drivers/gpu/drm/i915/i915_drv.h        |    4 ++++
>  drivers/gpu/drm/i915/i915_gem.c        |   28 +++++++++++++++++++++++-----
>  drivers/gpu/drm/i915/i915_gem_dmabuf.c |    5 ++---
>  drivers/gpu/drm/i915/i915_gem_stolen.c |    4 ++--
>  5 files changed, 34 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 14271aa..69969be 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1776,6 +1776,9 @@ int i915_driver_unload(struct drm_device *dev)
>  
>  	destroy_workqueue(dev_priv->wq);
>  
> +	if (dev_priv->slab)
> +		kmem_cache_destroy(dev_priv->slab);
> +
>  	pci_dev_put(dev_priv->bridge_dev);
>  	kfree(dev->dev_private);
>  
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 5a0e0cd..5084b29 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -398,6 +398,7 @@ struct intel_gmbus {
>  
>  typedef struct drm_i915_private {
>  	struct drm_device *dev;
> +	struct kmem_cache *slab;
>  
>  	const struct intel_device_info *info;
>  
> @@ -1341,12 +1342,15 @@ int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
>  int i915_gem_wait_ioctl(struct drm_device *dev, void *data,
>  			struct drm_file *file_priv);
>  void i915_gem_load(struct drm_device *dev);
> +void *i915_gem_object_alloc(struct drm_device *dev);
> +void i915_gem_object_free(struct drm_i915_gem_object *obj);
>  int i915_gem_init_object(struct drm_gem_object *obj);
>  void i915_gem_object_init(struct drm_i915_gem_object *obj,
>  			 const struct drm_i915_gem_object_ops *ops);
>  struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
>  						  size_t size);
>  void i915_gem_free_object(struct drm_gem_object *obj);
> +
>  int __must_check i915_gem_object_pin(struct drm_i915_gem_object *obj,
>  				     uint32_t alignment,
>  				     bool map_and_fenceable,
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 0349899..8183c0f 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -193,6 +193,18 @@ i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
>  	return 0;
>  }
>  
> +void *i915_gem_object_alloc(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	return kmem_cache_alloc(dev_priv->slab, GFP_KERNEL | __GFP_ZERO);
> +}
> +
> +void i915_gem_object_free(struct drm_i915_gem_object *obj)
> +{
> +	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
> +	kmem_cache_free(dev_priv->slab, obj);
> +}
> +
>  static int
>  i915_gem_create(struct drm_file *file,
>  		struct drm_device *dev,
> @@ -216,7 +228,7 @@ i915_gem_create(struct drm_file *file,
>  	if (ret) {
>  		drm_gem_object_release(&obj->base);
>  		i915_gem_info_remove_obj(dev->dev_private, obj->base.size);
> -		kfree(obj);
> +		i915_gem_object_free(obj);
>  		return ret;
>  	}
>  
> @@ -3780,12 +3792,12 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
>  	struct address_space *mapping;
>  	u32 mask;
>  
> -	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> +	obj = i915_gem_object_alloc(dev);
>  	if (obj == NULL)
>  		return NULL;
>  
>  	if (drm_gem_object_init(dev, &obj->base, size) != 0) {
> -		kfree(obj);
> +		i915_gem_object_free(obj);
>  		return NULL;
>  	}
>  
> @@ -3868,7 +3880,7 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
>  	i915_gem_info_remove_obj(dev_priv, obj->base.size);
>  
>  	kfree(obj->bit_17);
> -	kfree(obj);
> +	i915_gem_object_free(obj);
>  }
>  
>  int
> @@ -4246,8 +4258,14 @@ init_ring_lists(struct intel_ring_buffer *ring)
>  void
>  i915_gem_load(struct drm_device *dev)
>  {
> -	int i;
>  	drm_i915_private_t *dev_priv = dev->dev_private;
> +	int i;
> +
> +	dev_priv->slab =
> +		kmem_cache_create("i915_gem_object",
> +				  sizeof(struct drm_i915_gem_object), 0,
> +				  SLAB_HWCACHE_ALIGN,
> +				  NULL);
>  
>  	INIT_LIST_HEAD(&dev_priv->mm.active_list);
>  	INIT_LIST_HEAD(&dev_priv->mm.inactive_list);
> diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> index ca3497e..f307e31 100644
> --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> @@ -276,8 +276,7 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
>  	if (IS_ERR(attach))
>  		return ERR_CAST(attach);
>  
> -
> -	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> +	obj = i915_gem_object_alloc(dev);
>  	if (obj == NULL) {
>  		ret = -ENOMEM;
>  		goto fail_detach;
> @@ -285,7 +284,7 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
>  
>  	ret = drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
>  	if (ret) {
> -		kfree(obj);
> +		i915_gem_object_free(obj);
>  		goto fail_detach;
>  	}
>  
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index 86c4af4..d7cfa71 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -261,7 +261,7 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
>  {
>  	struct drm_i915_gem_object *obj;
>  
> -	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> +	obj = i915_gem_object_alloc(dev);
>  	if (obj == NULL)
>  		return NULL;
>  
> @@ -286,7 +286,7 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
>  	return obj;
>  
>  cleanup:
> -	kfree(obj);
> +	i915_gem_object_free(obj);
>  	return NULL;
>  }
>  



-- 
Ben Widawsky, Intel Open Source Technology Center

  parent reply	other threads:[~2012-11-05 17:49 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-19 17:03 [PATCH 01/18] drm: Introduce drm_mm_create_block() Chris Wilson
2012-10-19 17:03 ` [PATCH 02/18] drm/i915: Fix detection of stolen base for gen2 Chris Wilson
2012-11-01 23:51   ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 03/18] drm/i915: Fix location of stolen memory register for SandyBridge+ Chris Wilson
2012-10-26 21:58   ` Ben Widawsky
2012-10-28  9:48     ` Chris Wilson
2012-10-28 17:52       ` Ben Widawsky
2012-11-02  0:08       ` Ben Widawsky
2012-11-02  8:54         ` Chris Wilson
2012-11-05 13:53           ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 04/18] drm/i915: Avoid clearing preallocated regions from the GTT Chris Wilson
2012-10-26 22:22   ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 05/18] drm: Introduce an iterator over holes in the drm_mm range manager Chris Wilson
2012-11-05 13:41   ` Ben Widawsky
2012-11-05 15:13     ` Chris Wilson
2012-10-19 17:03 ` [PATCH 06/18] drm/i915: Delay allocation of stolen space for FBC Chris Wilson
2012-11-05 13:44   ` Ben Widawsky
2012-11-05 15:24     ` Chris Wilson
2012-10-19 17:03 ` [PATCH 07/18] drm/i915: Defer allocation of stolen memory for FBC until actual first use Chris Wilson
2012-11-05 15:00   ` Ben Widawsky
2012-11-05 15:28     ` Chris Wilson
2012-11-05 15:32       ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 08/18] drm/i915: Allow objects to be created with no backing pages, but stolen space Chris Wilson
2012-10-19 17:03 ` [PATCH 09/18] drm/i915: Differentiate between prime and stolen objects Chris Wilson
2012-10-19 17:03 ` [PATCH 10/18] drm/i915: Support readback of stolen objects upon error Chris Wilson
2012-11-05 15:41   ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 11/18] drm/i915: Handle stolen objects in pwrite Chris Wilson
2012-10-19 17:03 ` [PATCH 12/18] drm/i915: Handle stolen objects for pread Chris Wilson
2012-10-19 17:03 ` [PATCH 13/18] drm/i915: Introduce i915_gem_object_create_stolen() Chris Wilson
2012-11-05 16:32   ` Ben Widawsky
2012-11-05 16:59     ` Chris Wilson
2012-11-05 17:34       ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 14/18] drm/i915: Allocate fbcon from stolen memory Chris Wilson
2012-10-19 17:03 ` [PATCH 15/18] drm/i915: Allocate ringbuffers " Chris Wilson
2012-10-19 17:03 ` [PATCH 16/18] drm/i915: Allocate overlay registers " Chris Wilson
2012-11-05 17:39   ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 17/18] drm/i915: Use a slab for object allocation Chris Wilson
2012-10-24 20:21   ` Paulo Zanoni
2012-11-05 17:49   ` Ben Widawsky [this message]
2012-11-05 20:57     ` Chris Wilson
2012-11-07 13:59       ` Ben Widawsky
2012-11-05 18:07   ` Ben Widawsky
2012-11-05 18:10     ` Ben Widawsky
2012-10-19 17:03 ` [PATCH 18/18] drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl Chris Wilson
2012-10-22 22:21   ` Jesse Barnes
2012-10-23  7:20     ` Daniel Vetter
2012-10-23 17:50       ` Eric Anholt
2012-10-26 21:47 ` [PATCH 01/18] drm: Introduce drm_mm_create_block() Ben Widawsky
2012-10-28  9:57   ` Chris Wilson
2012-10-28 18:12     ` Ben Widawsky
2012-10-28 18:14       ` Ben Widawsky

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