Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH 13/29] params: Add a per cpu module param type | Date | Fri, 22 Mar 2013 18:25:07 -0700 |
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From: Andi Kleen <ak@linux.intel.com>
This is mainly useful for simple statistic counters. Essentially read-only, writing only clears.
Cc: rusty@rustcorp.co.au Signed-off-by: Andi Kleen <ak@linux.intel.com> --- include/linux/moduleparam.h | 4 ++++ kernel/params.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 137b419..e3c41af 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -394,6 +394,10 @@ extern int param_set_bint(const char *val, const struct kernel_param *kp); #define param_get_bint param_get_int #define param_check_bint param_check_int +/* A per cpu read-only unsigned integer. Useful for counters. */ +extern struct kernel_param_ops param_ops_percpu_uint; +#define param_check_percpu_uint(name, p) param_check_uint + /** * module_param_array - a parameter which is an array of some type * @name: the name of the array variable diff --git a/kernel/params.c b/kernel/params.c index ed35345..1a8a1ca 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -499,6 +499,34 @@ struct kernel_param_ops param_ops_string = { }; EXPORT_SYMBOL(param_ops_string); +/* Per CPU read only module param. */ + +static int param_percpu_uint_set(const char *val, const struct kernel_param *kp) +{ + int cpu; + + /* just clear on any write */ + for_each_possible_cpu(cpu) + *per_cpu_ptr((unsigned * __percpu)(kp->arg), cpu) = 0; + return 0; +} + +static int param_percpu_uint_get(char *buffer, const struct kernel_param *kp) +{ + int cpu; + unsigned count = 0; + + for_each_possible_cpu(cpu) + count += *per_cpu_ptr((unsigned * __percpu)(kp->arg), cpu); + return sprintf(buffer, "%u", count); +} + +struct kernel_param_ops param_ops_percpu_uint = { + .set = param_percpu_uint_set, + .get = param_percpu_uint_get, +}; +EXPORT_SYMBOL(param_ops_percpu_uint); + /* sysfs output in /sys/modules/XYZ/parameters/ */ #define to_module_attr(n) container_of(n, struct module_attribute, attr) #define to_module_kobject(n) container_of(n, struct module_kobject, kobj) -- 1.7.7.6
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