Re: [PATCH 4/4] dmapool: Improve memory usage for devices which can't cross boundaries

2007-09-26 Thread David Miller 
From: Matthew Wilcox <[EMAIL PROTECTED]>
Date: Wed, 26 Sep 2007 15:01:19 -0400

> The previous implementation simply refused to allocate more than a
> boundary's worth of data from an entire page.  Some users didn't know
> this, so specified things like SMP_CACHE_BYTES, not realising the
> horrible waste of memory that this was.  It's fairly easy to correct
> this problem, just by ensuring we don't cross a boundary within a page.
> This even helps drivers like EHCI (which can't cross a 4k boundary)
> on machines with larger page sizes.
> 
> Signed-off-by: Matthew Wilcox <[EMAIL PROTECTED]>

This one looks good to me:

Acked-by: David S. Miller <[EMAIL PROTECTED]>
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Re: [PATCH 4/4] dmapool: Improve memory usage for devices which can't cross boundaries

2007-09-26 Thread roel 
Matthew Wilcox wrote:

[...]

> @@ -142,14 +144,13 @@ struct dma_pool *dma_pool_create(const char *name, 
> struct device *dev,
>   if ((size % align) != 0)
>   size = ALIGN(size, align);
>  
> - if (allocation == 0) {
> - if (PAGE_SIZE < size)
> - allocation = size;
> - else
> - allocation = PAGE_SIZE;
> - // FIXME: round up for less fragmentation
> - } else if (allocation < size)
> + allocation = max_t(size_t, size, PAGE_SIZE);
> +
> + if (!boundary) {
> + boundary = allocation;
> + } else if ((boundary < size) || (boundary & (boundary - 1))) {
>   return NULL;
> + }

if (!boundary)
boundary = allocation;
else if (boundary < size || boundary & (boundary - 1))
return NULL;

[...]

> @@ -190,11 +192,14 @@ struct dma_pool *dma_pool_create(const char *name, 
> struct device *dev,
>  static void pool_initialise_page(struct dma_pool *pool, struct dma_page 
> *page)
>  {
>   unsigned int offset = 0;
> + unsigned int next_boundary = pool->boundary;
>  
>   do {
>   unsigned int next = offset + pool->size;
> - if (unlikely((next + pool->size) >= pool->allocation))
> - next = pool->allocation;
> + if (unlikely((next + pool->size) >= next_boundary)) {

if (unlikely(next + pool->size >= next_boundary)) {

[...]
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[PATCH 4/4] dmapool: Improve memory usage for devices which can't cross boundaries

2007-09-26 Thread Matthew Wilcox 
The previous implementation simply refused to allocate more than a
boundary's worth of data from an entire page.  Some users didn't know
this, so specified things like SMP_CACHE_BYTES, not realising the
horrible waste of memory that this was.  It's fairly easy to correct
this problem, just by ensuring we don't cross a boundary within a page.
This even helps drivers like EHCI (which can't cross a 4k boundary)
on machines with larger page sizes.

Signed-off-by: Matthew Wilcox <[EMAIL PROTECTED]>
---
 mm/dmapool.c |   29 +
 1 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 4418e4d..cc43d20 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -43,6 +43,7 @@ struct dma_pool { /* the pool */
size_t size;
struct device *dev;
size_t allocation;
+   size_t boundary;
char name[32];
wait_queue_head_t waitq;
struct list_head pools;
@@ -107,7 +108,7 @@ static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
  * @dev: device that will be doing the DMA
  * @size: size of the blocks in this pool.
  * @align: alignment requirement for blocks; must be a power of two
- * @allocation: returned blocks won't cross this boundary (or zero)
+ * @boundary: returned blocks won't cross this power of two boundary
  * Context: !in_interrupt()
  *
  * Returns a dma allocation pool with the requested characteristics, or
@@ -117,15 +118,16 @@ static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
  * cache flushing primitives.  The actual size of blocks allocated may be
  * larger than requested because of alignment.
  *
- * If allocation is nonzero, objects returned from dma_pool_alloc() won't
+ * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
  * cross that size boundary.  This is useful for devices which have
  * addressing restrictions on individual DMA transfers, such as not crossing
  * boundaries of 4KBytes.
  */
 struct dma_pool *dma_pool_create(const char *name, struct device *dev,
-size_t size, size_t align, size_t allocation)
+size_t size, size_t align, size_t boundary)
 {
struct dma_pool *retval;
+   size_t allocation;
 
if (align == 0) {
align = 1;
@@ -142,14 +144,13 @@ struct dma_pool *dma_pool_create(const char *name, struct 
device *dev,
if ((size % align) != 0)
size = ALIGN(size, align);
 
-   if (allocation == 0) {
-   if (PAGE_SIZE < size)
-   allocation = size;
-   else
-   allocation = PAGE_SIZE;
-   // FIXME: round up for less fragmentation
-   } else if (allocation < size)
+   allocation = max_t(size_t, size, PAGE_SIZE);
+
+   if (!boundary) {
+   boundary = allocation;
+   } else if ((boundary < size) || (boundary & (boundary - 1))) {
return NULL;
+   }
 
retval = kmalloc_node(sizeof *retval, GFP_KERNEL, dev_to_node(dev));
if (!retval)
@@ -162,6 +163,7 @@ struct dma_pool *dma_pool_create(const char *name, struct 
device *dev,
INIT_LIST_HEAD(>page_list);
spin_lock_init(>lock);
retval->size = size;
+   retval->boundary = boundary;
retval->allocation = allocation;
init_waitqueue_head(>waitq);
 
@@ -190,11 +192,14 @@ struct dma_pool *dma_pool_create(const char *name, struct 
device *dev,
 static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
 {
unsigned int offset = 0;
+   unsigned int next_boundary = pool->boundary;
 
do {
unsigned int next = offset + pool->size;
-   if (unlikely((next + pool->size) >= pool->allocation))
-   next = pool->allocation;
+   if (unlikely((next + pool->size) >= next_boundary)) {
+   next = next_boundary;
+   next_boundary += pool->boundary;
+   }
*(int *)(page->vaddr + offset) = next;
offset = next;
} while (offset < pool->allocation);
-- 
1.5.3.1

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[PATCH 4/4] dmapool: Improve memory usage for devices which can't cross boundaries

2007-09-26 Thread Matthew Wilcox 
The previous implementation simply refused to allocate more than a
boundary's worth of data from an entire page.  Some users didn't know
this, so specified things like SMP_CACHE_BYTES, not realising the
horrible waste of memory that this was.  It's fairly easy to correct
this problem, just by ensuring we don't cross a boundary within a page.
This even helps drivers like EHCI (which can't cross a 4k boundary)
on machines with larger page sizes.

Signed-off-by: Matthew Wilcox [EMAIL PROTECTED]
---
 mm/dmapool.c |   29 +
 1 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 4418e4d..cc43d20 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -43,6 +43,7 @@ struct dma_pool { /* the pool */
size_t size;
struct device *dev;
size_t allocation;
+   size_t boundary;
char name[32];
wait_queue_head_t waitq;
struct list_head pools;
@@ -107,7 +108,7 @@ static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
  * @dev: device that will be doing the DMA
  * @size: size of the blocks in this pool.
  * @align: alignment requirement for blocks; must be a power of two
- * @allocation: returned blocks won't cross this boundary (or zero)
+ * @boundary: returned blocks won't cross this power of two boundary
  * Context: !in_interrupt()
  *
  * Returns a dma allocation pool with the requested characteristics, or
@@ -117,15 +118,16 @@ static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
  * cache flushing primitives.  The actual size of blocks allocated may be
  * larger than requested because of alignment.
  *
- * If allocation is nonzero, objects returned from dma_pool_alloc() won't
+ * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
  * cross that size boundary.  This is useful for devices which have
  * addressing restrictions on individual DMA transfers, such as not crossing
  * boundaries of 4KBytes.
  */
 struct dma_pool *dma_pool_create(const char *name, struct device *dev,
-size_t size, size_t align, size_t allocation)
+size_t size, size_t align, size_t boundary)
 {
struct dma_pool *retval;
+   size_t allocation;
 
if (align == 0) {
align = 1;
@@ -142,14 +144,13 @@ struct dma_pool *dma_pool_create(const char *name, struct 
device *dev,
if ((size % align) != 0)
size = ALIGN(size, align);
 
-   if (allocation == 0) {
-   if (PAGE_SIZE  size)
-   allocation = size;
-   else
-   allocation = PAGE_SIZE;
-   // FIXME: round up for less fragmentation
-   } else if (allocation  size)
+   allocation = max_t(size_t, size, PAGE_SIZE);
+
+   if (!boundary) {
+   boundary = allocation;
+   } else if ((boundary  size) || (boundary  (boundary - 1))) {
return NULL;
+   }
 
retval = kmalloc_node(sizeof *retval, GFP_KERNEL, dev_to_node(dev));
if (!retval)
@@ -162,6 +163,7 @@ struct dma_pool *dma_pool_create(const char *name, struct 
device *dev,
INIT_LIST_HEAD(retval-page_list);
spin_lock_init(retval-lock);
retval-size = size;
+   retval-boundary = boundary;
retval-allocation = allocation;
init_waitqueue_head(retval-waitq);
 
@@ -190,11 +192,14 @@ struct dma_pool *dma_pool_create(const char *name, struct 
device *dev,
 static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
 {
unsigned int offset = 0;
+   unsigned int next_boundary = pool-boundary;
 
do {
unsigned int next = offset + pool-size;
-   if (unlikely((next + pool-size) = pool-allocation))
-   next = pool-allocation;
+   if (unlikely((next + pool-size) = next_boundary)) {
+   next = next_boundary;
+   next_boundary += pool-boundary;
+   }
*(int *)(page-vaddr + offset) = next;
offset = next;
} while (offset  pool-allocation);
-- 
1.5.3.1

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Re: [PATCH 4/4] dmapool: Improve memory usage for devices which can't cross boundaries

2007-09-26 Thread roel 
Matthew Wilcox wrote:

[...]

 @@ -142,14 +144,13 @@ struct dma_pool *dma_pool_create(const char *name, 
 struct device *dev,
   if ((size % align) != 0)
   size = ALIGN(size, align);
  
 - if (allocation == 0) {
 - if (PAGE_SIZE  size)
 - allocation = size;
 - else
 - allocation = PAGE_SIZE;
 - // FIXME: round up for less fragmentation
 - } else if (allocation  size)
 + allocation = max_t(size_t, size, PAGE_SIZE);
 +
 + if (!boundary) {
 + boundary = allocation;
 + } else if ((boundary  size) || (boundary  (boundary - 1))) {
   return NULL;
 + }

if (!boundary)
boundary = allocation;
else if (boundary  size || boundary  (boundary - 1))
return NULL;

[...]

 @@ -190,11 +192,14 @@ struct dma_pool *dma_pool_create(const char *name, 
 struct device *dev,
  static void pool_initialise_page(struct dma_pool *pool, struct dma_page 
 *page)
  {
   unsigned int offset = 0;
 + unsigned int next_boundary = pool-boundary;
  
   do {
   unsigned int next = offset + pool-size;
 - if (unlikely((next + pool-size) = pool-allocation))
 - next = pool-allocation;
 + if (unlikely((next + pool-size) = next_boundary)) {

if (unlikely(next + pool-size = next_boundary)) {

[...]
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Re: [PATCH 4/4] dmapool: Improve memory usage for devices which can't cross boundaries

2007-09-26 Thread David Miller 
From: Matthew Wilcox [EMAIL PROTECTED]
Date: Wed, 26 Sep 2007 15:01:19 -0400

 The previous implementation simply refused to allocate more than a
 boundary's worth of data from an entire page.  Some users didn't know
 this, so specified things like SMP_CACHE_BYTES, not realising the
 horrible waste of memory that this was.  It's fairly easy to correct
 this problem, just by ensuring we don't cross a boundary within a page.
 This even helps drivers like EHCI (which can't cross a 4k boundary)
 on machines with larger page sizes.
 
 Signed-off-by: Matthew Wilcox [EMAIL PROTECTED]

This one looks good to me:

Acked-by: David S. Miller [EMAIL PROTECTED]
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/