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author | Dave Hansen <dave@linux.vnet.ibm.com> | 2008-10-16 07:01:46 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-16 20:21:31 +0200 |
commit | 22b8ce94708f7cdf0b04965c6f7443dfd374c35c (patch) | |
tree | e2d5b60e9b881cf251185b23c3853c8b3e52d42a /kernel/profile.c | |
parent | rlimit: permit setting RLIMIT_NOFILE to RLIM_INFINITY (diff) | |
download | linux-22b8ce94708f7cdf0b04965c6f7443dfd374c35c.tar.xz linux-22b8ce94708f7cdf0b04965c6f7443dfd374c35c.zip |
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 <dave@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/profile.c')
-rw-r--r-- | kernel/profile.c | 41 |
1 files changed, 31 insertions, 10 deletions
diff --git a/kernel/profile.c b/kernel/profile.c index cd26bed4cc26..a9e422df6bf6 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -22,6 +22,8 @@ #include <linux/cpu.h> #include <linux/highmem.h> #include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> #include <asm/sections.h> #include <asm/irq_regs.h> #include <asm/ptrace.h> @@ -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) |