From e057d7aea9d8f2a46cd440d8bfb72245d4e72d79 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Mon, 15 Dec 2008 20:26:48 -0800 Subject: cpumask: add sysfs displays for configured and disabled cpu maps Impact: add new sysfs files. Add sysfs files "kernel_max" and "offline" to display the max CPU index allowed (NR_CPUS-1), and the map of cpus that are offline. Cpus can be offlined via HOTPLUG, disabled by the BIOS ACPI tables, or if they exceed the number of cpus allowed by the NR_CPUS config option, or the "maxcpus=NUM" kernel start parameter. The "possible_cpus=NUM" parameter can also extend the number of possible cpus allowed, in which case the cpus not present at startup will be in the offline state. (These cpus can be HOTPLUGGED ON after system startup [pending a follow-on patch to provide the capability via the /sys/devices/sys/cpu/cpuN/online mechanism to bring them online.]) By design, the "offlined cpus > possible cpus" display will always use the following formats: * all possible cpus online: "x$" or "x-y$" * some possible cpus offline: ".*,x$" or ".*,x-y$" where: x == number of possible cpus (nr_cpu_ids); and y == number of cpus >= NR_CPUS or maxcpus (if y > x). One use of this feature is for distros to select (or configure) the appropriate kernel to install for the resident system. Notes: * cpus offlined <= possible cpus will be printed for all architectures. * cpus offlined > possible cpus will only be printed for arches that set 'total_cpus' [X86 only in this patch]. Based on tip/cpus4096 + .../rusty/linux-2.6-for-ingo.git/master + x86-only-patches sent 12/15. Signed-off-by: Mike Travis Signed-off-by: Rusty Russell --- include/linux/smp.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/smp.h') diff --git a/include/linux/smp.h b/include/linux/smp.h index 3f9a60043a97..0d5770c2e43a 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -21,6 +21,9 @@ struct call_single_data { u16 priv; }; +/* total number of cpus in this system (may exceed NR_CPUS) */ +extern unsigned int total_cpus; + #ifdef CONFIG_SMP #include -- cgit v1.2.3 From 54b11e6d57a10aa9d0009efd93873e17bffd5d30 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 30 Dec 2008 09:05:16 +1030 Subject: cpumask: smp_call_function_many() Impact: Implementation change to remove cpumask_t from stack. Actually change smp_call_function_mask() to smp_call_function_many(). We avoid cpumasks on the stack in this version. (S390 has its own version, but that's going away apparently). We have to do some dancing to figure out if 0 or 1 other cpus are in the mask supplied and the online mask without allocating a tmp cpumask. It's still fairly cheap. We allocate the cpumask at the end of the call_function_data structure: if allocation fails we fallback to smp_call_function_single rather than using the baroque quiescing code (which needs a cpumask on stack). (Thanks to Hiroshi Shimamoto for spotting several bugs in previous versions!) Signed-off-by: Rusty Russell Signed-off-by: Mike Travis Cc: Hiroshi Shimamoto Cc: npiggin@suse.de Cc: axboe@kernel.dk --- include/linux/smp.h | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'include/linux/smp.h') diff --git a/include/linux/smp.h b/include/linux/smp.h index 2f85f3b04bc4..b82466968101 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -67,15 +67,16 @@ extern void smp_cpus_done(unsigned int max_cpus); * Call a function on all other processors */ int smp_call_function(void(*func)(void *info), void *info, int wait); -/* Deprecated: use smp_call_function_many() which uses a cpumask ptr. */ -int smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info, - int wait); +void smp_call_function_many(const struct cpumask *mask, + void (*func)(void *info), void *info, bool wait); -static inline void smp_call_function_many(const struct cpumask *mask, - void (*func)(void *info), void *info, - int wait) +/* Deprecated: Use smp_call_function_many which takes a pointer to the mask. */ +static inline int +smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info, + int wait) { - smp_call_function_mask(*mask, func, info, wait); + smp_call_function_many(&mask, func, info, wait); + return 0; } int smp_call_function_single(int cpuid, void (*func) (void *info), void *info, -- cgit v1.2.3