Re: Set huge_page_size on 32bit system

On Fri, Jun 26, 2026 at 01:24:15PM +0900, Kyotaro Horiguchi wrote:
> We could also make the later calculation use a wider integer type, but
> such a value would not be usable anyway on a platform where it does
> not fit in Size. So it seems better to reject it earlier in
> check_huge_page_size(), before reaching CreateAnonymousSegment().

The top of guc.h includes the following thing:
/*
* Maximum for integer GUC variables that are measured in kilobytes of memory.
* This value is chosen to ensure that the corresponding number of bytes fits
* into a variable of type size_t or ssize_t. Be sure to compute the number
* of bytes like "guc_var * (Size) 1024" to avoid int-width overflow.
*/
#if SIZEOF_SIZE_T > 4
#define MAX_KILOBYTES INT_MAX
#else
#define MAX_KILOBYTES (INT_MAX / 1024)
#endif

So it seems to me that the mistake is that huge_page_size uses INT_MAX
as upper bound. We should use MAX_KILOBYTES instead; this definition
exists to exactly prevent this kind of computation mistake in 32b
environments.
--
Michael