On 04/20/2011 10:01 AM, Borislav Petkov wrote: > On Wed, Apr 20, 2011 at 04:46:22PM +0100, Robert Whitton wrote: >> >>> On Wed, Apr 20, 2011 at 05:19:41PM +0200, Clemens Ladisch wrote: >>>>> Unfortunately in common with a large number of hardware platforms >>>>> background scrubbing isn't supported in the hardware (even though ECC >>>>> error correction is supported) and thus there is no BIOS option to >>>>> enable it. >>>> >>>> Which hardware platform is this? AFAICT all architectures with ECC >>>> (old AMD64, Family 0Fh, Family 10h) also have scrubbing support. >>>> If your BIOS is too dumb, just try enabling it directly (bits 0-4 of >>>> PCI configuration register 0x58 in function 3 of the CPU's northbridge >>>> device, see the BIOS and Kernel's Developer's Guide for details). >>> >>> Or even better, if on AMD, you can build the amd64_edac module >>> (CONFIG_EDAC_AMD64) and do >>> >>> echo > /sys/devices/system/edac/mc/mc/sdram_scrub_rate >>> >>> where x is the scrubbing bandwidth in bytes/sec and y is the memory >>> controller on the machine, i.e. node. >> >> Unfortunately that also isn't an option on my platform(s). There surely must be a way for a module to be able to get a mapping for each physical page of memory in the system and to be able to use that mapping to do atomic read/writes to scrub the memory. > > For such questions I've added just the right ML to Cc :). There was a thread back in 2009 cwith the subject "marching through all physical memory in software" that discussed some of the issues of a software background scrub. Chris -- Chris Friesen Software Developer GENBAND chris.friesen@xxxxxxxxxxx www.genband.com -- 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>