diff mbox series

[4/6] drm/i915: use vmap in i915_gem_object_map

Message ID 20200918163724.2511-5-hch@lst.de
State New
Headers show
Series [1/6] zsmalloc: switch from alloc_vm_area to get_vm_area | expand

Commit Message

Christoph Hellwig Sept. 18, 2020, 4:37 p.m. UTC
i915_gem_object_map implements fairly low-level vmap functionality in
a driver.  Split it into two helpers, one for remapping kernel memory
which can use vmap, and one for I/O memory that uses vmap_pfn.

The only practical difference is that alloc_vm_area prefeaults the
vmalloc area PTEs, which doesn't seem to be required here for the
kernel memory case (and could be added to vmap using a flag if actually
required).

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/i915/Kconfig              |   1 +
 drivers/gpu/drm/i915/gem/i915_gem_pages.c | 101 ++++++++++------------
 2 files changed, 47 insertions(+), 55 deletions(-)

Comments

Tvrtko Ursulin Sept. 23, 2020, 9:52 a.m. UTC | #1
On 18/09/2020 17:37, Christoph Hellwig wrote:
> i915_gem_object_map implements fairly low-level vmap functionality in
> a driver.  Split it into two helpers, one for remapping kernel memory
> which can use vmap, and one for I/O memory that uses vmap_pfn.
> 
> The only practical difference is that alloc_vm_area prefeaults the
> vmalloc area PTEs, which doesn't seem to be required here for the
> kernel memory case (and could be added to vmap using a flag if actually
> required).

Patch looks good to me.

Series did not get a CI run from our side because of a different base so 
I don't know if you would like to have a run there? If so you would need 
to rebase against git://anongit.freedesktop.org/drm-tip drm-tip and you 
could even send a series to intel-gfx-trybot@lists.freedesktop.org, 
suppressing cc, to check it out without sending a copy to the real 
mailing list.

Regards,

Tvrtko

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/gpu/drm/i915/Kconfig              |   1 +
>   drivers/gpu/drm/i915/gem/i915_gem_pages.c | 101 ++++++++++------------
>   2 files changed, 47 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index 9afa5c4a6bf006..1e1cb245fca778 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -25,6 +25,7 @@ config DRM_I915
>   	select CRC32
>   	select SND_HDA_I915 if SND_HDA_CORE
>   	select CEC_CORE if CEC_NOTIFIER
> +	select VMAP_PFN
>   	help
>   	  Choose this option if you have a system that has "Intel Graphics
>   	  Media Accelerator" or "HD Graphics" integrated graphics,
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> index e8a083743e0927..90029ea83aede9 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
> @@ -234,50 +234,24 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
>   	return err;
>   }
>   
> -static inline pte_t iomap_pte(resource_size_t base,
> -			      dma_addr_t offset,
> -			      pgprot_t prot)
> -{
> -	return pte_mkspecial(pfn_pte((base + offset) >> PAGE_SHIFT, prot));
> -}
> -
>   /* The 'mapping' part of i915_gem_object_pin_map() below */
> -static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
> +static void *i915_gem_object_map_page(struct drm_i915_gem_object *obj,
>   				 enum i915_map_type type)
>   {
> -	unsigned long n_pte = obj->base.size >> PAGE_SHIFT;
> -	struct sg_table *sgt = obj->mm.pages;
> -	pte_t *stack[32], **mem;
> -	struct vm_struct *area;
> +	unsigned long n_pages = obj->base.size >> PAGE_SHIFT, i;
> +	struct page *stack[32], **pages = stack, *page;
> +	struct sgt_iter iter;
>   	pgprot_t pgprot;
> -
> -	if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC)
> -		return NULL;
> -
> -	/* A single page can always be kmapped */
> -	if (n_pte == 1 && type == I915_MAP_WB)
> -		return kmap(sg_page(sgt->sgl));
> -
> -	mem = stack;
> -	if (n_pte > ARRAY_SIZE(stack)) {
> -		/* Too big for stack -- allocate temporary array instead */
> -		mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
> -		if (!mem)
> -			return NULL;
> -	}
> -
> -	area = alloc_vm_area(obj->base.size, mem);
> -	if (!area) {
> -		if (mem != stack)
> -			kvfree(mem);
> -		return NULL;
> -	}
> +	void *vaddr;
>   
>   	switch (type) {
>   	default:
>   		MISSING_CASE(type);
>   		fallthrough;	/* to use PAGE_KERNEL anyway */
>   	case I915_MAP_WB:
> +		/* A single page can always be kmapped */
> +		if (n_pages == 1)
> +			return kmap(sg_page(obj->mm.pages->sgl));
>   		pgprot = PAGE_KERNEL;
>   		break;
>   	case I915_MAP_WC:
> @@ -285,30 +259,44 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
>   		break;
>   	}
>   
> -	if (i915_gem_object_has_struct_page(obj)) {
> -		struct sgt_iter iter;
> -		struct page *page;
> -		pte_t **ptes = mem;
> -
> -		for_each_sgt_page(page, iter, sgt)
> -			**ptes++ = mk_pte(page, pgprot);
> -	} else {
> -		resource_size_t iomap;
> -		struct sgt_iter iter;
> -		pte_t **ptes = mem;
> -		dma_addr_t addr;
> +	if (n_pages > ARRAY_SIZE(stack)) {
> +		/* Too big for stack -- allocate temporary array instead */
> +		pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
> +		if (!pages)
> +			return NULL;
> +	}
>   
> -		iomap = obj->mm.region->iomap.base;
> -		iomap -= obj->mm.region->region.start;
> +	for_each_sgt_page(page, iter, obj->mm.pages)
> +		pages[i++] = page;
> +	vaddr = vmap(pages, n_pages, 0, pgprot);
> +	if (pages != stack)
> +		kvfree(pages);
> +	return vaddr;
> +}
>   
> -		for_each_sgt_daddr(addr, iter, sgt)
> -			**ptes++ = iomap_pte(iomap, addr, pgprot);
> +static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj)
> +{
> +	resource_size_t iomap = obj->mm.region->iomap.base -
> +		obj->mm.region->region.start;
> +	unsigned long n_pfn = obj->base.size >> PAGE_SHIFT;
> +	unsigned long stack[32], *pfns = stack, i;
> +	struct sgt_iter iter;
> +	dma_addr_t addr;
> +	void *vaddr;
> +
> +	if (n_pfn > ARRAY_SIZE(stack)) {
> +		/* Too big for stack -- allocate temporary array instead */
> +		pfns = kvmalloc_array(n_pfn, sizeof(*pfns), GFP_KERNEL);
> +		if (!pfns)
> +			return NULL;
>   	}
>   
> -	if (mem != stack)
> -		kvfree(mem);
> -
> -	return area->addr;
> +	for_each_sgt_daddr(addr, iter, obj->mm.pages)
> +		pfns[i++] = (iomap + addr) >> PAGE_SHIFT;
> +	vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL_IO));
> +	if (pfns != stack)
> +		kvfree(pfns);
> +	return vaddr;
>   }
>   
>   /* get, pin, and map the pages of the object into kernel space */
> @@ -360,7 +348,10 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
>   	}
>   
>   	if (!ptr) {
> -		ptr = i915_gem_object_map(obj, type);
> +		if (i915_gem_object_has_struct_page(obj))
> +			ptr = i915_gem_object_map_page(obj, type);
> +		else if (type == I915_MAP_WC)
> +			ptr = i915_gem_object_map_pfn(obj);
>   		if (!ptr) {
>   			err = -ENOMEM;
>   			goto err_unpin;
>
Christoph Hellwig Sept. 23, 2020, 1:41 p.m. UTC | #2
On Wed, Sep 23, 2020 at 10:52:33AM +0100, Tvrtko Ursulin wrote:
>
> On 18/09/2020 17:37, Christoph Hellwig wrote:
>> i915_gem_object_map implements fairly low-level vmap functionality in
>> a driver.  Split it into two helpers, one for remapping kernel memory
>> which can use vmap, and one for I/O memory that uses vmap_pfn.
>>
>> The only practical difference is that alloc_vm_area prefeaults the
>> vmalloc area PTEs, which doesn't seem to be required here for the
>> kernel memory case (and could be added to vmap using a flag if actually
>> required).
>
> Patch looks good to me.
>
> Series did not get a CI run from our side because of a different base so I 
> don't know if you would like to have a run there? If so you would need to 
> rebase against git://anongit.freedesktop.org/drm-tip drm-tip and you could 
> even send a series to intel-gfx-trybot@lists.freedesktop.org, suppressing 
> cc, to check it out without sending a copy to the real mailing list.

It doesn't seem like I can post to any freedesktop list, as I always
get rejection messages.  But I'll happily prepare a branch if one
of you an feed it into your CI.
Tvrtko Ursulin Sept. 23, 2020, 1:58 p.m. UTC | #3
On 23/09/2020 14:41, Christoph Hellwig wrote:
> On Wed, Sep 23, 2020 at 10:52:33AM +0100, Tvrtko Ursulin wrote:
>>
>> On 18/09/2020 17:37, Christoph Hellwig wrote:
>>> i915_gem_object_map implements fairly low-level vmap functionality in
>>> a driver.  Split it into two helpers, one for remapping kernel memory
>>> which can use vmap, and one for I/O memory that uses vmap_pfn.
>>>
>>> The only practical difference is that alloc_vm_area prefeaults the
>>> vmalloc area PTEs, which doesn't seem to be required here for the
>>> kernel memory case (and could be added to vmap using a flag if actually
>>> required).
>>
>> Patch looks good to me.
>>
>> Series did not get a CI run from our side because of a different base so I
>> don't know if you would like to have a run there? If so you would need to
>> rebase against git://anongit.freedesktop.org/drm-tip drm-tip and you could
>> even send a series to intel-gfx-trybot@lists.freedesktop.org, suppressing
>> cc, to check it out without sending a copy to the real mailing list.
> 
> It doesn't seem like I can post to any freedesktop list, as I always
> get rejection messages.  But I'll happily prepare a branch if one
> of you an feed it into your CI.

That's fine, just ping me and I will forward it for testing, thanks!

Regards,

Tvrtko
Christoph Hellwig Sept. 23, 2020, 2:44 p.m. UTC | #4
On Wed, Sep 23, 2020 at 02:58:43PM +0100, Tvrtko Ursulin wrote:
>>> Series did not get a CI run from our side because of a different base so I
>>> don't know if you would like to have a run there? If so you would need to
>>> rebase against git://anongit.freedesktop.org/drm-tip drm-tip and you could
>>> even send a series to intel-gfx-trybot@lists.freedesktop.org, suppressing
>>> cc, to check it out without sending a copy to the real mailing list.
>>
>> It doesn't seem like I can post to any freedesktop list, as I always
>> get rejection messages.  But I'll happily prepare a branch if one
>> of you an feed it into your CI.
>
> That's fine, just ping me and I will forward it for testing, thanks!

    git://git.infradead.org/users/hch/misc.git i915-vmap-wip

Gitweb:

    http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/i915-vmap-wip

note that this includes a new commit to clean up one of the recent
commits in the code.
Tvrtko Ursulin Sept. 24, 2020, 12:22 p.m. UTC | #5
On 23/09/2020 15:44, Christoph Hellwig wrote:
> On Wed, Sep 23, 2020 at 02:58:43PM +0100, Tvrtko Ursulin wrote:
>>>> Series did not get a CI run from our side because of a different base so I
>>>> don't know if you would like to have a run there? If so you would need to
>>>> rebase against git://anongit.freedesktop.org/drm-tip drm-tip and you could
>>>> even send a series to intel-gfx-trybot@lists.freedesktop.org, suppressing
>>>> cc, to check it out without sending a copy to the real mailing list.
>>>
>>> It doesn't seem like I can post to any freedesktop list, as I always
>>> get rejection messages.  But I'll happily prepare a branch if one
>>> of you an feed it into your CI.
>>
>> That's fine, just ping me and I will forward it for testing, thanks!
> 
>      git://git.infradead.org/users/hch/misc.git i915-vmap-wip
> 
> Gitweb:
> 
>      http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/i915-vmap-wip
> 
> note that this includes a new commit to clean up one of the recent
> commits in the code.

CI says series looks good from the i915 perspective (*).

I don't know how will you handle it logistically, but when you have 
final version I am happy to re-read and r-b the i915 patches.


Regards,

Tvrtko

*)
https://patchwork.freedesktop.org/series/82051/
Christoph Hellwig Sept. 24, 2020, 1:23 p.m. UTC | #6
On Thu, Sep 24, 2020 at 01:22:35PM +0100, Tvrtko Ursulin wrote:
> CI says series looks good from the i915 perspective (*).
>
> I don't know how will you handle it logistically, but when you have final 
> version I am happy to re-read and r-b the i915 patches.

I'll resend the series later today, and will make sure you are on the
Cc list.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index 9afa5c4a6bf006..1e1cb245fca778 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -25,6 +25,7 @@  config DRM_I915
 	select CRC32
 	select SND_HDA_I915 if SND_HDA_CORE
 	select CEC_CORE if CEC_NOTIFIER
+	select VMAP_PFN
 	help
 	  Choose this option if you have a system that has "Intel Graphics
 	  Media Accelerator" or "HD Graphics" integrated graphics,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index e8a083743e0927..90029ea83aede9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -234,50 +234,24 @@  int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
 	return err;
 }
 
-static inline pte_t iomap_pte(resource_size_t base,
-			      dma_addr_t offset,
-			      pgprot_t prot)
-{
-	return pte_mkspecial(pfn_pte((base + offset) >> PAGE_SHIFT, prot));
-}
-
 /* The 'mapping' part of i915_gem_object_pin_map() below */
-static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
+static void *i915_gem_object_map_page(struct drm_i915_gem_object *obj,
 				 enum i915_map_type type)
 {
-	unsigned long n_pte = obj->base.size >> PAGE_SHIFT;
-	struct sg_table *sgt = obj->mm.pages;
-	pte_t *stack[32], **mem;
-	struct vm_struct *area;
+	unsigned long n_pages = obj->base.size >> PAGE_SHIFT, i;
+	struct page *stack[32], **pages = stack, *page;
+	struct sgt_iter iter;
 	pgprot_t pgprot;
-
-	if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC)
-		return NULL;
-
-	/* A single page can always be kmapped */
-	if (n_pte == 1 && type == I915_MAP_WB)
-		return kmap(sg_page(sgt->sgl));
-
-	mem = stack;
-	if (n_pte > ARRAY_SIZE(stack)) {
-		/* Too big for stack -- allocate temporary array instead */
-		mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
-		if (!mem)
-			return NULL;
-	}
-
-	area = alloc_vm_area(obj->base.size, mem);
-	if (!area) {
-		if (mem != stack)
-			kvfree(mem);
-		return NULL;
-	}
+	void *vaddr;
 
 	switch (type) {
 	default:
 		MISSING_CASE(type);
 		fallthrough;	/* to use PAGE_KERNEL anyway */
 	case I915_MAP_WB:
+		/* A single page can always be kmapped */
+		if (n_pages == 1)
+			return kmap(sg_page(obj->mm.pages->sgl));
 		pgprot = PAGE_KERNEL;
 		break;
 	case I915_MAP_WC:
@@ -285,30 +259,44 @@  static void *i915_gem_object_map(struct drm_i915_gem_object *obj,
 		break;
 	}
 
-	if (i915_gem_object_has_struct_page(obj)) {
-		struct sgt_iter iter;
-		struct page *page;
-		pte_t **ptes = mem;
-
-		for_each_sgt_page(page, iter, sgt)
-			**ptes++ = mk_pte(page, pgprot);
-	} else {
-		resource_size_t iomap;
-		struct sgt_iter iter;
-		pte_t **ptes = mem;
-		dma_addr_t addr;
+	if (n_pages > ARRAY_SIZE(stack)) {
+		/* Too big for stack -- allocate temporary array instead */
+		pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
+		if (!pages)
+			return NULL;
+	}
 
-		iomap = obj->mm.region->iomap.base;
-		iomap -= obj->mm.region->region.start;
+	for_each_sgt_page(page, iter, obj->mm.pages)
+		pages[i++] = page;
+	vaddr = vmap(pages, n_pages, 0, pgprot);
+	if (pages != stack)
+		kvfree(pages);
+	return vaddr;
+}
 
-		for_each_sgt_daddr(addr, iter, sgt)
-			**ptes++ = iomap_pte(iomap, addr, pgprot);
+static void *i915_gem_object_map_pfn(struct drm_i915_gem_object *obj)
+{
+	resource_size_t iomap = obj->mm.region->iomap.base -
+		obj->mm.region->region.start;
+	unsigned long n_pfn = obj->base.size >> PAGE_SHIFT;
+	unsigned long stack[32], *pfns = stack, i;
+	struct sgt_iter iter;
+	dma_addr_t addr;
+	void *vaddr;
+
+	if (n_pfn > ARRAY_SIZE(stack)) {
+		/* Too big for stack -- allocate temporary array instead */
+		pfns = kvmalloc_array(n_pfn, sizeof(*pfns), GFP_KERNEL);
+		if (!pfns)
+			return NULL;
 	}
 
-	if (mem != stack)
-		kvfree(mem);
-
-	return area->addr;
+	for_each_sgt_daddr(addr, iter, obj->mm.pages)
+		pfns[i++] = (iomap + addr) >> PAGE_SHIFT;
+	vaddr = vmap_pfn(pfns, n_pfn, pgprot_writecombine(PAGE_KERNEL_IO));
+	if (pfns != stack)
+		kvfree(pfns);
+	return vaddr;
 }
 
 /* get, pin, and map the pages of the object into kernel space */
@@ -360,7 +348,10 @@  void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 	}
 
 	if (!ptr) {
-		ptr = i915_gem_object_map(obj, type);
+		if (i915_gem_object_has_struct_page(obj))
+			ptr = i915_gem_object_map_page(obj, type);
+		else if (type == I915_MAP_WC)
+			ptr = i915_gem_object_map_pfn(obj);
 		if (!ptr) {
 			err = -ENOMEM;
 			goto err_unpin;