回复: Re: [PATCH] tools/virtio: Use the __GFP_ZERO flag of kmalloc to complete the memory initialization.

[崔涛 <cuitao@xxxxxxxxxx>]

Sorry, this is a stupid mistake.

 

I wonder if the gfp parameter in static inline void *kmalloc(size_t s, gfp_t gfp) can be deleted if it is not used.

 

Or would be better to move memset to kmalloc.

Like this:

#define __GFP_ZERO 0x1

static inline void *kmalloc(size_t s, gfp_t gfp)

{

void *p;

if (__kmalloc_fake)

return __kmalloc_fake;

 

p = malloc(s);

if (!p)

        return p;

 

if (gfp & __GFP_ZERO)

memset(p, 0, s);

return p;

}

----

 

主　题：Re: [PATCH] tools/virtio: Use the __GFP_ZERO flag of kmalloc to complete the memory initialization.
日　期：2024-06-06 08:29
发件人：jasowang
收件人：崔涛;

On Wed, Jun 5, 2024 at 9:56 PM cuitao wrote:
>
> Use the __GFP_ZERO flag of kmalloc to initialize memory while allocating it,
> without the need for an additional memset call.
>
> Signed-off-by: cuitao
> ---
> tools/virtio/linux/kernel.h | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
> index 6702008f7f5c..9e401fb7c215 100644
> --- a/tools/virtio/linux/kernel.h
> +++ b/tools/virtio/linux/kernel.h
> @@ -66,10 +66,7 @@ static inline void *kmalloc_array(unsigned n, size_t s, gfp_t gfp)
>
> static inline void *kzalloc(size_t s, gfp_t gfp)
> {
> - void *p = kmalloc(s, gfp);
> -
> - memset(p, 0, s);
> - return p;
> + return kmalloc(s, gfp | __GFP_ZERO);
> }
>
> static inline void *alloc_pages_exact(size_t s, gfp_t gfp)
> --
> 2.25.1
>

Does this really work?

extern void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
static inline void *kmalloc(size_t s, gfp_t gfp)
{
if (__kmalloc_fake)
return __kmalloc_fake;
return malloc(s);
}

Thanks