From 420f8f68c9c5148dddf946bebdbc7eacde2172cb Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 5 Nov 2005 17:25:54 +0100 Subject: [PATCH] x86_64: New heuristics to find out hotpluggable CPUs. With a NR_CPUS==128 kernel with CPU hotplug enabled we would waste 4MB on per CPU data of all possible CPUs. The reason was that HOTPLUG always set up possible map to NR_CPUS cpus and then we need to allocate that much (each per CPU data is roughly ~32k now) The underlying problem is that ACPI didn't tell us how many hotplug CPUs the platform supports. So the old code just assumed all, which would lead to this memory wastage. This implements some new heuristics: - If the BIOS specified disabled CPUs in the ACPI/mptables assume they can be enabled later (this is bending the ACPI specification a bit, but seems like a obvious extension) - The user can overwrite it with a new additionals_cpus=NUM option - Otherwise use half of the available CPUs or 2, whatever is more. Cc: ashok.raj@intel.com Cc: len.brown@intel.com Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- Documentation/x86_64/boot-options.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/x86_64/boot-options.txt') diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index ffe1c06..a831396 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -122,6 +122,9 @@ SMP cpumask=MASK only use cpus with bits set in mask + additional_cpus=NUM Allow NUM more CPUs for hotplug + (defaults are specified by the BIOS or half the available CPUs) + NUMA numa=off Only set up a single NUMA node spanning all memory. -- cgit v1.1 From e583538f077d5f70191670b47a046ba436ec3428 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 5 Nov 2005 17:25:54 +0100 Subject: [PATCH] x86_64: Log machine checks from boot on Intel systems The logging for boot errors was turned off because it was broken on some AMD systems. But give Intel EM64T systems a chance because they are supposed to be correct there. The advantage is that there is a chance to actually log uncorrected machine checks after the reset. Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- Documentation/x86_64/boot-options.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Documentation/x86_64/boot-options.txt') diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index a831396..aaabb58 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -7,10 +7,12 @@ Machine check mce=off disable machine check mce=bootlog Enable logging of machine checks left over from booting. - Disabled by default because some BIOS leave bogus ones. + Disabled by default on AMD because some BIOS leave bogus ones. If your BIOS doesn't do that it's a good idea to enable though to make sure you log even machine check events that result - in a reboot. + in a reboot. On Intel systems it is enabled by default. + mce=nobootlog + Disable boot machine check logging. mce=tolerancelevel (number) 0: always panic, 1: panic if deadlock possible, 2: try to avoid panic, 3: never panic or exit (for testing) -- cgit v1.1 From 9e43e1b7c7c9872da032442d8e4bb112a02d16f4 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 5 Nov 2005 17:25:54 +0100 Subject: [PATCH] x86_64: Remove CONFIG_CHECKING and add command line option for pagefault tracing CONFIG_CHECKING covered some debugging code used in the early times of the port. But it wasn't even SMP safe for quite some time and the bugs it checked for seem to be gone. This patch removes all the code to verify GS at kernel entry. There haven't been any new bugs in this area for a long time. Previously it also covered the sysctl for the page fault tracing. That didn't make much sense because that code was unconditionally compiled in. I made that a boot option now because it is typically only useful at boot. Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- Documentation/x86_64/boot-options.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/x86_64/boot-options.txt') diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index aaabb58..e566aff 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -193,6 +193,9 @@ Debugging kstack=N Print that many words from the kernel stack in oops dumps. + pagefaulttrace Dump all page faults. Only useful for extreme debugging + and will create a lot of output. + Misc noreplacement Don't replace instructions with more appropiate ones -- cgit v1.1