Re: [PATCH v2 2/2] malloc: Improve MAP_HUGETLB with glibc.malloc.hugetlb=2

[DJ Delorie <dj@redhat.com>]

Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
> diff --git a/malloc/arena.c b/malloc/arena.c
> index a1a75e5a2b..c73f68890d 100644
> --- a/malloc/arena.c
> +++ b/malloc/arena.c
> @@ -312,10 +312,17 @@ ptmalloc_init (void)
>  # endif
>    TUNABLE_GET (mxfast, size_t, TUNABLE_CALLBACK (set_mxfast));
>    TUNABLE_GET (hugetlb, size_t, TUNABLE_CALLBACK (set_hugetlb));
> +
>    if (mp_.hp_pagesize > 0)
> -    /* Force mmap for main arena instead of sbrk, so hugepages are explicitly
> -       used.  */
> -    __always_fail_morecore = true;
> +    {
> +      /* Force mmap for main arena instead of sbrk, so MAP_HUGETLB is always
> +         tried.  Also tune the mmap threshold, so allocation smaller than the
> +	 large page will also try to use large pages by falling back
> +	 to sysmalloc_mmap_fallback on sysmalloc.  */
> +      if (!TUNABLE_IS_INITIALIZED (mmap_threshold))
> +	do_set_mmap_threshold (mp_.hp_pagesize);
> +      __always_fail_morecore = true;
> +    }
>  }
>  
>  /* Managing heaps and arenas (for concurrent threads) */

Ok.

LGTM
Reviewed-by: DJ Delorie <dj@redhat.com>