From f1477c4b74d46f7e85b658473b3a37c87d00b886 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 1 Aug 2013 15:00:02 +0200 Subject: [PATCH] mkswap: add note about swap header limit to the man page Signed-off-by: Karel Zak --- disk-utils/mkswap.8 | 3 +++ 1 file changed, 3 insertions(+) diff --git a/disk-utils/mkswap.8 b/disk-utils/mkswap.8 index 6435dd6aee..68cc40ba37 100644 --- a/disk-utils/mkswap.8 +++ b/disk-utils/mkswap.8 @@ -107,6 +107,9 @@ It is roughly 2GiB on i386, PPC, m68k and ARM, 1GiB on sparc, 512MiB on mips, 128GiB on alpha, and 3TiB on sparc64. For kernels after 2.3.3 (May 1999) there is no such limitation. +The maximum number of the pages that is possible to address by swap area header +is 4294967295 (UINT_MAX). The remaining space on the swap device is ignored. + Note that before version 2.1.117 the kernel allocated one byte for each page, while it now allocates two bytes, so that taking into use a swap area of 2 GiB might require 2 MiB of kernel memory. -- 2.47.2