Re: [PATCH v9 2/5] genalloc:support allocating specific region

[Scott Wood]

On Mon, 2015-09-14 at 09:38 +0800, Zhao Qiang wrote:
> Add new algo for genalloc, it reserve a specific region of
> memory matching the size requirement (no alignment constraint)
> 
> Signed-off-by: Zhao Qiang 
> ---
> Changes for v9:
>   - reserve a specific region, if the return region
>   - is not during the specific region, return fail.
> 
>  include/linux/genalloc.h | 11 +++
>  lib/genalloc.c   | 30 ++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
> index aaf3dc2..85e3b2f 100644
> --- a/include/linux/genalloc.h
> +++ b/include/linux/genalloc.h
> @@ -82,6 +82,13 @@ struct genpool_data_align {
>   int align;  /* alignment by bytes for starting address */
>  };
>  
> +/*
> + *  gen_pool data descriptor for gen_pool_fixed_fit.
> + */
> +struct genpool_data_fixed {
> + unsigned long offset;   /* The offset of the specific region */
> +};
> +
>  extern struct gen_pool *gen_pool_create(int, int);
>  extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned 
> long);
>  extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
> @@ -121,6 +128,10 @@ extern unsigned long gen_pool_first_fit(unsigned long 
> *map, unsigned long size,
>   unsigned long start, unsigned int nr, void *data,
>   struct gen_pool *pool);
>  
> +extern unsigned long gen_pool_fixed_fit(unsigned long *map,
> + unsigned long size, unsigned long start, unsigned int nr,
> + void *data, struct gen_pool *pool);
> +

"fixed fit" doesn't make much sense...  How about "fixed_alloc"?

 /**
> + * gen_pool_fixed_fit - reserve a specific region of
> + * matching the size requirement (no alignment constraint)
> + * @map: The address to base the search on
> + * @size: The bitmap size in bits
> + * @start: The bitnumber to start searching at
> + * @nr: The number of zeroed bits we're looking for
> + * @data: data for alignment
> + * @pool: pool to get order from
> + */
> +unsigned long gen_pool_fixed_fit(unsigned long *map, unsigned long size,
> + unsigned long start, unsigned int nr, void *data,
> + struct gen_pool *pool)
> +{
> + struct genpool_data_fixed *fixed_data;
> + int order;
> + unsigned long offset_bit;
> + unsigned long start_bit;
> +
> + fixed_data = data;
> + order = pool->min_alloc_order;
> + offset_bit = fixed_data->offset >> order;
> + start_bit = bitmap_find_next_zero_area(map, size,
> + start + offset_bit, nr, 0);
> + if (start_bit != offset_bit)
> + start_bit = size;
> + return start_bit;
> +}
> +EXPORT_SYMBOL(gen_pool_fixed_fit);

This would be simpler with bitmap_allocate_region().

-Scott

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Re: [PATCH v9 2/5] genalloc:support allocating specific region

[Scott Wood]

On Thu, 2015-09-17 at 15:19 -0500, Scott Wood wrote:
> On Mon, 2015-09-14 at 09:38 +0800, Zhao Qiang wrote:
> > Add new algo for genalloc, it reserve a specific region of
> > memory matching the size requirement (no alignment constraint)
> > 
> > Signed-off-by: Zhao Qiang 
> > ---
> > Changes for v9:
> >   - reserve a specific region, if the return region
> >   - is not during the specific region, return fail.
> > 
> >  include/linux/genalloc.h | 11 +++
> >  lib/genalloc.c   | 30 ++
> >  2 files changed, 41 insertions(+)
> > 
> > diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
> > index aaf3dc2..85e3b2f 100644
> > --- a/include/linux/genalloc.h
> > +++ b/include/linux/genalloc.h
> > @@ -82,6 +82,13 @@ struct genpool_data_align {
> >   int align;  /* alignment by bytes for starting address 
> > */
> >  };
> >  
> > +/*
> > + *  gen_pool data descriptor for gen_pool_fixed_fit.
> > + */
> > +struct genpool_data_fixed {
> > + unsigned long offset;   /* The offset of the specific 
> > region */
> > +};
> > +
> >  extern struct gen_pool *gen_pool_create(int, int);
> >  extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned 
> > long);
> >  extern int gen_pool_add_virt(struct gen_pool *, unsigned long, 
> > phys_addr_t,
> > @@ -121,6 +128,10 @@ extern unsigned long gen_pool_first_fit(unsigned 
> > long 
> > *map, unsigned long size,
> >   unsigned long start, unsigned int nr, void *data,
> >   struct gen_pool *pool);
> >  
> > +extern unsigned long gen_pool_fixed_fit(unsigned long *map,
> > + unsigned long size, unsigned long start, unsigned int nr,
> > + void *data, struct gen_pool *pool);
> > +
> 
> "fixed fit" doesn't make much sense...  How about "fixed_alloc"?
> 
>  /**
> > + * gen_pool_fixed_fit - reserve a specific region of
> > + * matching the size requirement (no alignment constraint)
> > + * @map: The address to base the search on
> > + * @size: The bitmap size in bits
> > + * @start: The bitnumber to start searching at
> > + * @nr: The number of zeroed bits we're looking for
> > + * @data: data for alignment
> > + * @pool: pool to get order from
> > + */
> > +unsigned long gen_pool_fixed_fit(unsigned long *map, unsigned long size,
> > + unsigned long start, unsigned int nr, void *data,
> > + struct gen_pool *pool)
> > +{
> > + struct genpool_data_fixed *fixed_data;
> > + int order;
> > + unsigned long offset_bit;
> > + unsigned long start_bit;
> > +
> > + fixed_data = data;
> > + order = pool->min_alloc_order;
> > + offset_bit = fixed_data->offset >> order;
> > + start_bit = bitmap_find_next_zero_area(map, size,
> > + start + offset_bit, nr, 0);
> > + if (start_bit != offset_bit)
> > + start_bit = size;
> > + return start_bit;
> > +}
> > +EXPORT_SYMBOL(gen_pool_fixed_fit);
> 
> This would be simpler with bitmap_allocate_region().

Never mind, that doesn't fit with how the algorithm is used by the caller, 
and unlike genalloc isn't atomic.

-Scott

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[PATCH v9 2/5] genalloc:support allocating specific region

[Zhao Qiang]

Add new algo for genalloc, it reserve a specific region of
memory matching the size requirement (no alignment constraint)

Signed-off-by: Zhao Qiang 
---
Changes for v9:
- reserve a specific region, if the return region
- is not during the specific region, return fail.

 include/linux/genalloc.h | 11 +++
 lib/genalloc.c   | 30 ++
 2 files changed, 41 insertions(+)

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index aaf3dc2..85e3b2f 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -82,6 +82,13 @@ struct genpool_data_align {
int align;  /* alignment by bytes for starting address */
 };
 
+/*
+ *  gen_pool data descriptor for gen_pool_fixed_fit.
+ */
+struct genpool_data_fixed {
+   unsigned long offset;   /* The offset of the specific region */
+};
+
 extern struct gen_pool *gen_pool_create(int, int);
 extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
 extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
@@ -121,6 +128,10 @@ extern unsigned long gen_pool_first_fit(unsigned long 
*map, unsigned long size,
unsigned long start, unsigned int nr, void *data,
struct gen_pool *pool);
 
+extern unsigned long gen_pool_fixed_fit(unsigned long *map,
+   unsigned long size, unsigned long start, unsigned int nr,
+   void *data, struct gen_pool *pool);
+
 extern unsigned long gen_pool_first_fit_align(unsigned long *map,
unsigned long size, unsigned long start, unsigned int nr,
void *data, struct gen_pool *pool);
diff --git a/lib/genalloc.c b/lib/genalloc.c
index b8762b1..87a045e 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -554,6 +554,36 @@ unsigned long gen_pool_first_fit_align(unsigned long *map, 
unsigned long size,
 EXPORT_SYMBOL(gen_pool_first_fit_align);
 
 /**
+ * gen_pool_fixed_fit - reserve a specific region of
+ * matching the size requirement (no alignment constraint)
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @data: data for alignment
+ * @pool: pool to get order from
+ */
+unsigned long gen_pool_fixed_fit(unsigned long *map, unsigned long size,
+   unsigned long start, unsigned int nr, void *data,
+   struct gen_pool *pool)
+{
+   struct genpool_data_fixed *fixed_data;
+   int order;
+   unsigned long offset_bit;
+   unsigned long start_bit;
+
+   fixed_data = data;
+   order = pool->min_alloc_order;
+   offset_bit = fixed_data->offset >> order;
+   start_bit = bitmap_find_next_zero_area(map, size,
+   start + offset_bit, nr, 0);
+   if (start_bit != offset_bit)
+   start_bit = size;
+   return start_bit;
+}
+EXPORT_SYMBOL(gen_pool_fixed_fit);
+
+/**
  * gen_pool_first_fit_order_align - find the first available region
  * of memory matching the size requirement. The region will be aligned
  * to the order of the size specified.
-- 
2.1.0.27.g96db324

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