Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12, 2014 at 12:19:54PM +0200, Michal Nazarewicz wrote:
> On Thu, Jun 12 2014, Joonsoo Kim wrote:
> > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> >
> > Signed-off-by: Joonsoo Kim
>
> Acked-by: Michal Nazarewicz
>
> > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > index bc4c171..9bc9340 100644
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> > unsigned long base_pfn;
> > unsigned long count;
>
> Have you considered replacing count with maxno?
No, I haven't.
I think that count is better than maxno, since it represent number of
pages in this region.
>
> > unsigned long *bitmap;
> > + int order_per_bit; /* Order of pages represented by one bit */
>
> I'd make it unsigned.
Will fix it.
> > struct mutexlock;
> > };
> >
> > +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int
> > count)
>
> For consistency cma_clear_bitmap would make more sense I think. On the
> other hand, you're just moving stuff around so perhaps renaming the
> function at this point is not worth it any more.
Will fix it.
> > +{
> > + unsigned long bitmapno, nr_bits;
> > +
> > + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> > + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> > +
> > + mutex_lock(&cma->lock);
> > + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> > + mutex_unlock(&cma->lock);
> > +}
> > +
> > static int __init cma_activate_area(struct cma *cma)
> > {
> > - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> > + int bitmap_maxno = cma_bitmap_maxno(cma);
> > + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> > unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> > unsigned i = cma->count >> pageblock_order;
> > struct zone *zone;
>
> bitmap_maxno is never used again, perhaps:
>
> + int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
>
> instead? Up to you.
Okay!!
Thanks.
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Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
Joonsoo Kim writes:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim
Reviewed-by: Aneesh Kumar K.V
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
> struct mutexlock;
> };
>
> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>
> static DEFINE_MUTEX(cma_mutex);
>
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int
> align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
> * @base: Base address of the reserved area optional, use 0 for any
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> *
> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
> */
> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment,
> + phys_addr_t alignment, int order_per_bit,
> struct cma **res_cma, bool fixed)
> {
> struct cma *cma = &cma_areas[cma_area_count];
> @@ -269,6 +300,8 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
> base = ALIGN(base, alignment);
> size = ALIGN(size, alignment);
> limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>
> /* Reserve memory */
> if (base && fixed) {
> @@ -294,6 +327,7 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
>*/
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> *res_cma = cma;
> cma_area_count++;
>
> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> res_cma, fixed);
> if (ret)
> return ret;
> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> return 0;
> }
>
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
> - mutex_unlock(&cma->lock);
> -}
> -
> /**
> * dma_alloc_from_contiguous() - allocate pages from contiguous area
> * @dev: Pointer to device for which the allocation is performed.
> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned
> long pfn, int count)
> static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> unsigned int align)
> {
> - unsigned long mask, pfn, pageno, start = 0;
> + unsigned long ma
Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12 2014, Joonsoo Kim wrote:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim
Acked-by: Michal Nazarewicz
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
Have you considered replacing count with maxno?
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
I'd make it unsigned.
> struct mutexlock;
> };
>
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int
> count)
For consistency cma_clear_bitmap would make more sense I think. On the
other hand, you're just moving stuff around so perhaps renaming the
function at this point is not worth it any more.
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
bitmap_maxno is never used again, perhaps:
+ int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
instead? Up to you.
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz(o o)
ooo +--ooO--(_)--Ooo--
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Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On 06/12/2014 11:21 AM, Joonsoo Kim wrote:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim
Acked-by: Zhang Yanfei
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
> struct mutexlock;
> };
>
> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>
> static DEFINE_MUTEX(cma_mutex);
>
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int
> align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
> * @base: Base address of the reserved area optional, use 0 for any
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> *
> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
> */
> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment,
> + phys_addr_t alignment, int order_per_bit,
> struct cma **res_cma, bool fixed)
> {
> struct cma *cma = &cma_areas[cma_area_count];
> @@ -269,6 +300,8 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
> base = ALIGN(base, alignment);
> size = ALIGN(size, alignment);
> limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>
> /* Reserve memory */
> if (base && fixed) {
> @@ -294,6 +327,7 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
>*/
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> *res_cma = cma;
> cma_area_count++;
>
> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> res_cma, fixed);
> if (ret)
> return ret;
> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> return 0;
> }
>
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
> - mutex_unlock(&cma->lock);
> -}
> -
> /**
> * dma_alloc_from_contiguous() - allocate pages from contiguous area
> * @dev: Pointer to device for which the allocation is performed.
> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned
> long pfn, int count)
> static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> unsigned int align)
> {
> - unsigned long mask, pfn, pageno, start
Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12, 2014 at 04:08:11PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> >
> > Signed-off-by: Joonsoo Kim
> Acked-by: Minchan Kim
>
Thanks.
[snip...]
> > /**
> > * dma_alloc_from_contiguous() - allocate pages from contiguous area
> > * @dev: Pointer to device for which the allocation is performed.
> > @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned
> > long pfn, int count)
> > static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> >unsigned int align)
> > {
> > - unsigned long mask, pfn, pageno, start = 0;
> > + unsigned long mask, pfn, start = 0;
> > + unsigned long bitmap_maxno, bitmapno, nr_bits;
>
> Just Nit: bitmap_maxno, bitmap_no or something consistent.
> I know you love consistent when I read description in first patch
> in this patchset. ;-)
Yeah, I will fix it. :)
Thanks.
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Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On 06/12/2014 03:08 PM, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
>> ppc kvm's cma region management requires arbitrary bitmap granularity,
>> since they want to reserve very large memory and manage this region
>> with bitmap that one bit for several pages to reduce management overheads.
>> So support arbitrary bitmap granularity for following generalization.
>>
>> Signed-off-by: Joonsoo Kim
> Acked-by: Minchan Kim
>
> Just a nit below.
>
>>
>> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
>> index bc4c171..9bc9340 100644
>> --- a/drivers/base/dma-contiguous.c
>> +++ b/drivers/base/dma-contiguous.c
>> @@ -38,6 +38,7 @@ struct cma {
>> unsigned long base_pfn;
>> unsigned long count;
>> unsigned long *bitmap;
>> +int order_per_bit; /* Order of pages represented by one bit */
>> struct mutexlock;
>> };
>>
>> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>>
>> static DEFINE_MUTEX(cma_mutex);
>>
>> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int
>> align_order)
>> +{
>> +return (1 << (align_order >> cma->order_per_bit)) - 1;
>> +}
>> +
>> +static unsigned long cma_bitmap_maxno(struct cma *cma)
>> +{
>> +return cma->count >> cma->order_per_bit;
>> +}
>> +
>> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
>> +unsigned long pages)
>> +{
>> +return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
>> +}
>> +
>> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>> +{
>> +unsigned long bitmapno, nr_bits;
>> +
>> +bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
>> +nr_bits = cma_bitmap_pages_to_bits(cma, count);
>> +
>> +mutex_lock(&cma->lock);
>> +bitmap_clear(cma->bitmap, bitmapno, nr_bits);
>> +mutex_unlock(&cma->lock);
>> +}
>> +
>> static int __init cma_activate_area(struct cma *cma)
>> {
>> -int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
>> +int bitmap_maxno = cma_bitmap_maxno(cma);
>> +int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
>> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
>> unsigned i = cma->count >> pageblock_order;
>> struct zone *zone;
>> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
>> * @base: Base address of the reserved area optional, use 0 for any
>> * @limit: End address of the reserved memory (optional, 0 for any).
>> * @alignment: Alignment for the contiguous memory area, should be power of
>> 2
>> + * @order_per_bit: Order of pages represented by one bit on bitmap.
>> * @res_cma: Pointer to store the created cma region.
>> * @fixed: hint about where to place the reserved area
>> *
>> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
>> */
>> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
>> phys_addr_t base, phys_addr_t limit,
>> -phys_addr_t alignment,
>> +phys_addr_t alignment, int order_per_bit,
>> struct cma **res_cma, bool fixed)
>> {
>> struct cma *cma = &cma_areas[cma_area_count];
>> @@ -269,6 +300,8 @@ static int __init
>> __dma_contiguous_reserve_area(phys_addr_t size,
>> base = ALIGN(base, alignment);
>> size = ALIGN(size, alignment);
>> limit &= ~(alignment - 1);
>> +/* size should be aligned with order_per_bit */
>> +BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>>
>> /* Reserve memory */
>> if (base && fixed) {
>> @@ -294,6 +327,7 @@ static int __init
>> __dma_contiguous_reserve_area(phys_addr_t size,
>> */
>> cma->base_pfn = PFN_DOWN(base);
>> cma->count = size >> PAGE_SHIFT;
>> +cma->order_per_bit = order_per_bit;
>> *res_cma = cma;
>> cma_area_count++;
>>
>> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
>> phys_addr_t base,
>> {
>> int ret;
>>
>> -ret = __dma_contiguous_reserve_area(size, base, limit, 0,
>> +ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
>> res_cma, fixed);
>> if (ret)
>> return ret;
>> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t
>> size, phys_addr_t base,
>> return 0;
>> }
>>
>> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>> -{
>> -mutex_lock(&cma->lock);
>> -bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
>> -mutex_unlock(&cma->lock);
>> -}
>> -
>> /**
>> * dma_alloc_from_contiguous() - allocate pages from contiguous area
>> * @dev: Pointer to device for which the allocation is performed.
>> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned
>> long pfn, int count)
>> static struct page *_
Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim
Acked-by: Minchan Kim
Just a nit below.
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
> struct mutexlock;
> };
>
> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>
> static DEFINE_MUTEX(cma_mutex);
>
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int
> align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
> * @base: Base address of the reserved area optional, use 0 for any
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> *
> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
> */
> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment,
> + phys_addr_t alignment, int order_per_bit,
> struct cma **res_cma, bool fixed)
> {
> struct cma *cma = &cma_areas[cma_area_count];
> @@ -269,6 +300,8 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
> base = ALIGN(base, alignment);
> size = ALIGN(size, alignment);
> limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>
> /* Reserve memory */
> if (base && fixed) {
> @@ -294,6 +327,7 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
>*/
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> *res_cma = cma;
> cma_area_count++;
>
> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> res_cma, fixed);
> if (ret)
> return ret;
> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> return 0;
> }
>
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
> - mutex_unlock(&cma->lock);
> -}
> -
> /**
> * dma_alloc_from_contiguous() - allocate pages from contiguous area
> * @dev: Pointer to device for which the allocation is performed.
> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned
> long pfn, int count)
> static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> unsigned int align)
> {
> - uns
Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12, 2014 at 03:43:55PM +0900, Joonsoo Kim wrote:
> On Thu, Jun 12, 2014 at 03:06:10PM +0900, Minchan Kim wrote:
> > On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> > > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > > since they want to reserve very large memory and manage this region
> > > with bitmap that one bit for several pages to reduce management overheads.
> > > So support arbitrary bitmap granularity for following generalization.
> > >
> > > Signed-off-by: Joonsoo Kim
> > >
> > > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > > index bc4c171..9bc9340 100644
> > > --- a/drivers/base/dma-contiguous.c
> > > +++ b/drivers/base/dma-contiguous.c
> > > @@ -38,6 +38,7 @@ struct cma {
> > > unsigned long base_pfn;
> > > unsigned long count;
> > > unsigned long *bitmap;
> > > + int order_per_bit; /* Order of pages represented by one bit */
> >
> > Hmm, I'm not sure it's good as *general* interface even though it covers
> > existing usecases.
> >
> > It forces a cma area should be handled by same size unit. Right?
> > It's really important point for this patchset's motivation so I will stop
> > review and wait other opinions.
>
> If you pass 0 to order_per_bit, you can manage cma area in every
> size(page unit) you want. If you pass certain number to order_per_bit,
> you can allocate and release cma area in multiple of such page order.
>
> I think that this is more general implementation than previous versions.
Fair enough.
--
Kind regards,
Minchan Kim
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Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12, 2014 at 03:06:10PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> >
> > Signed-off-by: Joonsoo Kim
> >
> > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > index bc4c171..9bc9340 100644
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> > unsigned long base_pfn;
> > unsigned long count;
> > unsigned long *bitmap;
> > + int order_per_bit; /* Order of pages represented by one bit */
>
> Hmm, I'm not sure it's good as *general* interface even though it covers
> existing usecases.
>
> It forces a cma area should be handled by same size unit. Right?
> It's really important point for this patchset's motivation so I will stop
> review and wait other opinions.
If you pass 0 to order_per_bit, you can manage cma area in every
size(page unit) you want. If you pass certain number to order_per_bit,
you can allocate and release cma area in multiple of such page order.
I think that this is more general implementation than previous versions.
Thanks.
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Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
Hmm, I'm not sure it's good as *general* interface even though it covers
existing usecases.
It forces a cma area should be handled by same size unit. Right?
It's really important point for this patchset's motivation so I will stop
review and wait other opinions.
> struct mutexlock;
> };
>
> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>
> static DEFINE_MUTEX(cma_mutex);
>
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int
> align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
> * @base: Base address of the reserved area optional, use 0 for any
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> *
> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
> */
> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment,
> + phys_addr_t alignment, int order_per_bit,
> struct cma **res_cma, bool fixed)
> {
> struct cma *cma = &cma_areas[cma_area_count];
> @@ -269,6 +300,8 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
> base = ALIGN(base, alignment);
> size = ALIGN(size, alignment);
> limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>
> /* Reserve memory */
> if (base && fixed) {
> @@ -294,6 +327,7 @@ static int __init
> __dma_contiguous_reserve_area(phys_addr_t size,
>*/
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> *res_cma = cma;
> cma_area_count++;
>
> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> res_cma, fixed);
> if (ret)
> return ret;
> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base,
> return 0;
> }
>
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
> - mutex_unlock(&cma->lock);
> -}
> -
> /**
> * dma_alloc_from_contiguous() - allocate pages from contiguous area
> * @dev: Pointer to device for which the allocation is performed.
> @@ -345,7 +372,8 @@ static voi
