From 22b8ce94708f7cdf0b04965c6f7443dfd374c35c Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Wed, 15 Oct 2008 22:01:46 -0700 Subject: [PATCH] profiling: dynamically enable readprofile at runtime Way too often, I have a machine that exhibits some kind of crappy behavior. The CPU looks wedged in the kernel or it is spending way too much system time and I wonder what is responsible. I try to run readprofile. But, of course, Ubuntu doesn't enable it by default. Dang! The reason we boot-time enable it is that it takes a big bufffer that we generally can only bootmem alloc. But, does it hurt to at least try and runtime-alloc it? To use: echo 2 > /sys/kernel/profile Then run readprofile like normal. This should fix the compile issue with allmodconfig. I've compile-tested on a bunch more configs now including a few more architectures. Signed-off-by: Dave Hansen Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/ABI/testing/sysfs-profiling | 13 +++++++ include/linux/profile.h | 8 +++-- kernel/ksysfs.c | 35 +++++++++++++++++++ kernel/profile.c | 41 +++++++++++++++++------ 4 files changed, 84 insertions(+), 13 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-profiling diff --git a/Documentation/ABI/testing/sysfs-profiling b/Documentation/ABI/testing/sysfs-profiling new file mode 100644 index 00000000000..b02d8b8c173 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-profiling @@ -0,0 +1,13 @@ +What: /sys/kernel/profile +Date: September 2008 +Contact: Dave Hansen +Description: + /sys/kernel/profile is the runtime equivalent + of the boot-time profile= option. + + You can get the same effect running: + + echo 2 > /sys/kernel/profile + + as you would by issuing profile=2 on the boot + command line. diff --git a/include/linux/profile.h b/include/linux/profile.h index 7e7087239af..570045053ce 100644 --- a/include/linux/profile.h +++ b/include/linux/profile.h @@ -35,7 +35,9 @@ enum profile_type { extern int prof_on __read_mostly; /* init basic kernel profiler */ -void __init profile_init(void); +int profile_init(void); +int profile_setup(char *str); +int create_proc_profile(void); void profile_tick(int type); /* @@ -84,9 +86,9 @@ struct pt_regs; #define prof_on 0 -static inline void profile_init(void) +static inline int profile_init(void) { - return; + return 0; } static inline void profile_tick(int type) diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index e53bc30e9ba..08dd8ed86c7 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #define KERNEL_ATTR_RO(_name) \ @@ -53,6 +54,37 @@ static ssize_t uevent_helper_store(struct kobject *kobj, KERNEL_ATTR_RW(uevent_helper); #endif +#ifdef CONFIG_PROFILING +static ssize_t profiling_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", prof_on); +} +static ssize_t profiling_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int ret; + + if (prof_on) + return -EEXIST; + /* + * This eventually calls into get_option() which + * has a ton of callers and is not const. It is + * easiest to cast it away here. + */ + profile_setup((char *)buf); + ret = profile_init(); + if (ret) + return ret; + ret = create_proc_profile(); + if (ret) + return ret; + return count; +} +KERNEL_ATTR_RW(profiling); +#endif + #ifdef CONFIG_KEXEC static ssize_t kexec_loaded_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) @@ -109,6 +141,9 @@ static struct attribute * kernel_attrs[] = { &uevent_seqnum_attr.attr, &uevent_helper_attr.attr, #endif +#ifdef CONFIG_PROFILING + &profiling_attr.attr, +#endif #ifdef CONFIG_KEXEC &kexec_loaded_attr.attr, &kexec_crash_loaded_attr.attr, diff --git a/kernel/profile.c b/kernel/profile.c index cd26bed4cc2..a9e422df6bf 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #include #include #include @@ -50,11 +52,11 @@ static DEFINE_PER_CPU(int, cpu_profile_flip); static DEFINE_MUTEX(profile_flip_mutex); #endif /* CONFIG_SMP */ -static int __init profile_setup(char *str) +int profile_setup(char *str) { - static char __initdata schedstr[] = "schedule"; - static char __initdata sleepstr[] = "sleep"; - static char __initdata kvmstr[] = "kvm"; + static char schedstr[] = "schedule"; + static char sleepstr[] = "sleep"; + static char kvmstr[] = "kvm"; int par; if (!strncmp(str, sleepstr, strlen(sleepstr))) { @@ -100,14 +102,33 @@ static int __init profile_setup(char *str) __setup("profile=", profile_setup); -void __init profile_init(void) +int profile_init(void) { + int buffer_bytes; if (!prof_on) - return; + return 0; /* only text is profiled */ prof_len = (_etext - _stext) >> prof_shift; - prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t)); + buffer_bytes = prof_len*sizeof(atomic_t); + if (!slab_is_available()) { + prof_buffer = alloc_bootmem(buffer_bytes); + return 0; + } + + prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL); + if (prof_buffer) + return 0; + + prof_buffer = alloc_pages_exact(buffer_bytes, GFP_KERNEL|__GFP_ZERO); + if (prof_buffer) + return 0; + + prof_buffer = vmalloc(buffer_bytes); + if (prof_buffer) + return 0; + + return -ENOMEM; } /* Profile event notifications */ @@ -527,7 +548,7 @@ static void __init profile_nop(void *unused) { } -static int __init create_hash_tables(void) +static int create_hash_tables(void) { int cpu; @@ -575,14 +596,14 @@ out_cleanup: #define create_hash_tables() ({ 0; }) #endif -static int __init create_proc_profile(void) +int create_proc_profile(void) { struct proc_dir_entry *entry; if (!prof_on) return 0; if (create_hash_tables()) - return -1; + return -ENOMEM; entry = proc_create("profile", S_IWUSR | S_IRUGO, NULL, &proc_profile_operations); if (!entry) -- 2.41.0