Re: [Qemu-devel] [PATCH v1 01/17] qemu/obj_pool.h: introduce object allocation pool

[Eric Blake]

On 08/04/2014 09:33 PM, Ming Lei wrote:
> This patch introduces object allocation pool for speeding up
> object allocation in fast path.
> 
> Signed-off-by: Ming Lei <address@hidden>
> ---
>  include/qemu/obj_pool.h |   64 
> +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 64 insertions(+)
>  create mode 100644 include/qemu/obj_pool.h
> 
> diff --git a/include/qemu/obj_pool.h b/include/qemu/obj_pool.h
> new file mode 100644
> index 0000000..94b5f49
> --- /dev/null
> +++ b/include/qemu/obj_pool.h
> @@ -0,0 +1,64 @@
> +#ifndef QEMU_OBJ_POOL_HEAD
> +#define QEMU_OBJ_POOL_HEAD

Missing copyright boilerplate.  According to LICENSE, that makes this
file GPLv2+, but I'd much rather you make it explicit.

> +
> +typedef struct {
> +    unsigned int size;
> +    unsigned int cnt;

size_t feels better for sizes.  int may be okay in this case, but
definitely consider if size_t is appropriate.

> +
> +    void **free_obj;
> +    int free_idx;
> +
> +    char *objs;
> +} ObjPool;
> +
> +static inline void obj_pool_init(ObjPool *op, void *objs_buf, void 
> **free_objs,
> +                                 unsigned int obj_size, unsigned cnt)
> +{
> +    int i;
> +
> +    op->objs = (char *)objs_buf;

Why the cast? This is C, not C++.

> +    op->free_obj = free_objs;
> +    op->size = obj_size;
> +    op->cnt = cnt;
> +
> +    for (i = 0; i < op->cnt; i++) {
> +        op->free_obj[i] = (void *)&op->objs[i * op->size];

Again, why the cast?


> +static inline bool obj_pool_has_obj(ObjPool *op, void *obj)
> +{
> +    return op && (unsigned long)obj >= (unsigned long)&op->objs[0] &&
> +           (unsigned long)obj <=
> +           (unsigned long)&op->objs[(op->cnt - 1) * op->size];

uintptr_t, not unsigned long.  You are asking for problems on 64-bit
mingw, where unsigned long is 32 bits but uintptr_t is 64 bits.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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