On 27.04.2011 18:49, Randy Dunlap wrote: > On Wed, 27 Apr 2011 18:16:47 +0200 Stefan Assmann wrote: > >> Add Documentation/BadRAM.txt for in-depth information and update >> Documentation/kernel-parameters.txt. >> >> Signed-off-by: Stefan Assmann <sassmann@xxxxxxxxx> >> --- >> CREDITS | 9 + >> Documentation/BadRAM.txt | 369 +++++++++++++++++++++++++++++++++++ >> Documentation/kernel-parameters.txt | 5 + >> 3 files changed, 383 insertions(+), 0 deletions(-) >> create mode 100644 Documentation/BadRAM.txt > >> diff --git a/Documentation/BadRAM.txt b/Documentation/BadRAM.txt >> new file mode 100644 >> index 0000000..67a7ccc >> --- /dev/null >> +++ b/Documentation/BadRAM.txt >> @@ -0,0 +1,369 @@ > [snip] Spelling errors will be fixed in next version. Thanks! > I thought that /boot/grub/grub.conf was the current file name. (?) Not sure about that, some distros use menu.lst others grub.conf for GRUB. Also GRUB 2 uses /boot/grub/grub.cfg. Either of these would be fine with me, /boot/grub/menu.lst sometimes is a symlink to /boot/grub/grub.conf and I felt it's the most convenient one, but I have no strong preference here. > >> + >> +When the kernel now boots, it should not give any trouble with RAM. >> +Mind you, this is under the assumption that the kernel and its data >> +storage do not overlap an erroneous part. If they do, and the >> +kernel does not choke on it right away, BadRAM itself will stop the >> +system with a kernel panic. When the error is that low in memory, >> +you will need additional bootloader magic, to load the kernel at an >> +alternative address. >> + >> +Now look up your memory status with >> + >> + cat /proc/meminfo |grep HardwareCorrupted >> + >> +which prints a single line with information like >> + >> +HardwareCorrupted: 2048 kB >> + >> +The entry HardwareCorrupted: 2048k represents the loss of 2MB >> +of general purpose RAM due to the errors. Or, positively rephrased, >> +instead of throwing out 32MB as useless, you only throw out 2MB. >> +Note that 2048 kB equals 512 pages of 4kB. The size of a page is >> +defined by the processor architecture. >> + >> +If the system is stable (which you can test by compiling a few >> +kernels, and a few file finds in / or so) you can decide to add >> +the boot parameter to /boot/grub/menu.lst, in addition to any > > file name? See above comment. > >> +other boot parameters that may already be there. For example, >> + >> + kernel /boot/vmlinuz root=/dev/sda1 ro >> + >> +would become >> + >> + kernel /boot/vmlinuz root=/dev/sda1 ro badram=0x008042f4,0xff805fff >> + >> +Depending on how helpful your Linux distribution is, you may >> +have to add this feature again after upgrading your kernel. If >> +your boot loader is GRUB, you can always do this manually if you >> +rebooted before you remembered to make that adaption. >> + >> + > ... > > >> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt >> index f4a04c0..84f9ef5 100644 >> --- a/Documentation/kernel-parameters.txt >> +++ b/Documentation/kernel-parameters.txt >> @@ -373,6 +373,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. >> >> autotest [IA64] >> >> + badram= When CONFIG_MEMORY_FAILURE is set, this parameter >> + allows memory areas to be flagged as hwpoison. > > hwpoison?? undefined. BadRAM depends on hwpoison to be available. The code is located in mm/memory-failure.c. That file is only compiled if CONFIG_MEMORY_FAILURE is defined. grep CONFIG_MEMORY_FAILURE mm/Makefile obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o So for your question, if hwpoison is not available BadRAM also won't be available. > >> + Format: <addr>,<mask>[,...] >> + See Documentation/BadRAM.txt >> + > > > --- > ~Randy > *** Remember to use Documentation/SubmitChecklist when testing your code *** Thanks for the review Randy! Stefan -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>