From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- Documentation/memory.txt | 60 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 Documentation/memory.txt (limited to 'Documentation/memory.txt') diff --git a/Documentation/memory.txt b/Documentation/memory.txt new file mode 100644 index 000000000000..2b3dedd39538 --- /dev/null +++ b/Documentation/memory.txt @@ -0,0 +1,60 @@ +There are several classic problems related to memory on Linux +systems. + + 1) There are some buggy motherboards which cannot properly + deal with the memory above 16MB. Consider exchanging + your motherboard. + + 2) You cannot do DMA on the ISA bus to addresses above + 16M. Most device drivers under Linux allow the use + of bounce buffers which work around this problem. Drivers + that don't use bounce buffers will be unstable with + more than 16M installed. Drivers that use bounce buffers + will be OK, but may have slightly higher overhead. + + 3) There are some motherboards that will not cache above + a certain quantity of memory. If you have one of these + motherboards, your system will be SLOWER, not faster + as you add more memory. Consider exchanging your + motherboard. + +All of these problems can be addressed with the "mem=XXXM" boot option +(where XXX is the size of RAM to use in megabytes). +It can also tell Linux to use less memory than is actually installed. +If you use "mem=" on a machine with PCI, consider using "memmap=" to avoid +physical address space collisions. + +See the documentation of your boot loader (LILO, loadlin, etc.) about +how to pass options to the kernel. + +There are other memory problems which Linux cannot deal with. Random +corruption of memory is usually a sign of serious hardware trouble. +Try: + + * Reducing memory settings in the BIOS to the most conservative + timings. + + * Adding a cooling fan. + + * Not overclocking your CPU. + + * Having the memory tested in a memory tester or exchanged + with the vendor. Consider testing it with memtest86 yourself. + + * Exchanging your CPU, cache, or motherboard for one that works. + + * Disabling the cache from the BIOS. + + * Try passing the "mem=4M" option to the kernel to limit + Linux to using a very small amount of memory. Use "memmap="-option + together with "mem=" on systems with PCI to avoid physical address + space collisions. + + +Other tricks: + + * Try passing the "no-387" option to the kernel to ignore + a buggy FPU. + + * Try passing the "no-hlt" option to disable the potentially + buggy HLT instruction in your CPU. -- cgit v1.2.3