[PATCH 3/4] libm/stdlib: Realloc when shrinking by 2* or more

[Corinna Vinschen]

On Aug 11 16:05, Keith Packard via Newlib wrote:
> This reduces memory usage when reallocating objects much smaller.
> 
> Signed-off-by: Keith Packard <keithp@keithp.com>
> ---
>  newlib/libc/stdlib/nano-mallocr.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/newlib/libc/stdlib/nano-mallocr.c b/newlib/libc/stdlib/nano-mallocr.c
> index cef23977e..83234c618 100644
> --- a/newlib/libc/stdlib/nano-mallocr.c
> +++ b/newlib/libc/stdlib/nano-mallocr.c
> @@ -476,10 +476,8 @@ void * nano_realloc(RARG void * ptr, malloc_size_t size)
>          return NULL;
>      }
>  
> -    /* TODO: There is chance to shrink the chunk if newly requested
> -     * size is much small */
>      old_size = nano_malloc_usable_size(RCALL ptr);
> -    if (old_size >= size)
> +    if (size <= old_size && (old_size >> 1) < size)
>        return ptr;
>  
>      mem = nano_malloc(RCALL size);
> -- 
> 2.28.0

Ok, so this patch introduces the need for the conditional I complained
about in the previous patch.  IMO, the conditional should be moved
into this patch to introduce it together with the change it requires.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat