After expanding a freshly installed system for a while I find that the default value of LOG_BUF_SHIFT becomes inadequate. The kernel log buffer apparently is too small and the log is no longer complete (at least when viewed with demsg). I suggest raising it from 14 to 15 or 16 for a standard uniprocessor system. Reproducible: Always Steps to Reproduce: 1.dmesg|more 2. 3. Actual Results: dmesg output doesn't start where it should Expected Results: list the complete kernel startup log ZeusGentooTest ~ # emerge info Portage 2.0.51.19 (default-linux/x86/2005.0, gcc-3.4.3-20050110, glibc-2.3.4.20050125-r1, 2.6.11-gentoo-r6 i686) ================================================================= System uname: 2.6.11-gentoo-r6 i686 Intel(R) Pentium(R) 4 CPU 2.40GHz Gentoo Base System version 1.6.10 Python: dev-lang/python-2.3.5 [2.3.5 (#1, Mar 26 2005, 10:00:42)] ccache version 2.4 [enabled] dev-lang/python: 2.3.5 sys-devel/autoconf: 2.13, 2.59-r6 sys-devel/automake: 1.5, 1.9.5, 1.7.9-r1, 1.6.3, 1.4_p6, 1.8.5-r3 sys-devel/binutils: 2.15.92.0.2-r8 sys-devel/libtool: 1.5.14 virtual/os-headers: 2.6.8.1-r4 ACCEPT_KEYWORDS="x86 ~x86" AUTOCLEAN="yes" CFLAGS="-O3 -march=pentium4 -mtune=pentium4 -fforce-addr -momit-leaf-frame-pointer -fomit-frame-pointer -ftracer -pipe" CHOST="i686-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.4/env /usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config /usr/lib/X11/xkb /usr/share/config /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-O3 -march=pentium4 -mtune=pentium4 -fforce-addr -momit-leaf-frame-pointer -fomit-frame-pointer -ftracer -pipe -fvisibility-inlines-hidden" DISTDIR="/usr/portage/distfiles" FEATURES="autoaddcvs autoconfig candy ccache distlocks sandbox sfperms" GENTOO_MIRRORS="ftp://GentooMirror/gentoo" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" SYNC="rsync://GentooMirror/gentoo-portage" USE="x86 4kstacks X acpi alsa apm arts avi bdf berkdb bitmap-fonts cdr crypt cups curl directfb dvd dvdr emboss encode esd exif fam fbcon flac font-server foomaticdb fortran ftp gdbm gif gphoto2 gpm gtk gtk2 imlib ipv6 ithreads java javascript jpeg kde kdeenablefinal ldap libg++ libwww lm_sensors mad mikmod mmx motif mozilla moznocompose moznoirc moznomail mozsvg mp3 mpeg ncurses nls nptl nvidia offensive oggvorbis opengl oss pam pcmcia pdflib perl png pthreads python qt quicktime readline samba sblive scanner sdl slp spell sse ssl svg svga sysfs tcpd tiff truetype truetype-fonts type1-fonts unicode usb userlocales utf8 wifi xml2 xmms xscreensaver xv xvid zlib linguas_nl" Unset: ASFLAGS, CBUILD, CTARGET, LANG, LC_ALL, LDFLAGS ZeusGentooTest ~ #
Something weird is happening here. I suddenly discovered that increasing LOG_BUF_SHIFT from 14 to 16, which means from 16 KB to 64 KB according to the kernel comments, increases my kernel size with 1 MB! It used to be 1,6 MB and now its 2,6 MB: ZeusGentooTest ~ # ls -l /boot/bzI* -rw-r--r-- 1 root root 2641879 Apr 10 12:04 /boot/bzImage -rw-r--r-- 1 root root 1621948 Apr 8 16:36 /boot/bzImage~ I do not recall making any other changes but obviously some further testing may be needed.
Ingnore my previous comment. On other systems I did not reproduce this behaviour, so it must be something else. I apologize.
Please mail the linux kernel mailing list about this.
