RE: overly aggressive memory usage by sort.c

[Voelker, Bernhard]

Paul Eggert wrote:
> On 06/11/2012 03:02 AM, Paul Eggert wrote:
> > * src/sort.c (default_sort_size): Do not exceed 3/4 of total memory
> 
> Come to think of it, that patch is too conservative, as it
> limits things to at most 3/8 of total memory.  The 3/4 limit
> should be applied after 'size' is halved, not before.  Here's
> a better patch:

Then shouldn't the  * 0.75 be _instead_ of the /2 then?

>    size_t size = SIZE_MAX;
>    if (getrlimit (RLIMIT_DATA, &rlimit) == 0 && rlimit.rlim_cur < size)
>      size = rlimit.rlim_cur;
> @@ -1434,6 +1435,10 @@ default_sort_size (void)
>      size = rlimit.rlim_cur / 16 * 15;
>  #endif
>  
> +  /* Similarly, leave a 1/4 margin for physical memory.  */
> +  if (total * 0.75 < size)
> +    size = total * 0.75;
> +

and I'd put it before the rlimit calculation:
e.g. a system has 8GB of RAM, but the admin want sort to
only take 4GB. He'll use ulimit or plimit to 4GB.
With this patch, sort will only take 3GB.
Am I wrong?

Have a nice day,
Berny