1. On 32-bit x86, memtest=n tests only LOWMEM memory (~ 895 MiB), HIGHMEM is ignored 2. On 3.0.4-hardened-r5, HIGHMEM memory (HIGHMEM64G in my tests) is apparently ignored during memtest. Looking at arch/x86/mm/memtest.c, no special mapping is performed (kmap/kunmap?), so it seems that at most ~895 MiB can be tested in 32-bit x86 kernels. This might not appear like an important issue (as there are other memory testing tools available), but memtest is extremely useful for anti-forensic memory wiping on shutdown/reboot in security-oriented distributions like Liberté Linux and Tails, and there is no other good substitute. See, for instance, some background in Debian bug http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=646361. 3. Keywords: memtest, highmem, mm, security 4. Kernel version: 3.0.4-hardened-r5 (Gentoo) x86 32-bit with PAE -- Maxim Kammerer Liberté Linux (discussion / support: http://dee.su/liberte-contribute) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href