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authorDave Hansen <dave@linux.vnet.ibm.com>2008-10-15 22:01:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 11:21:31 -0700
commit22b8ce94708f7cdf0b04965c6f7443dfd374c35c (patch)
treee2d5b60e9b881cf251185b23c3853c8b3e52d42a /kernel/profile.c
parent0c2d64fb6cae9aae480f6a46cfe79f8d7d48b59f (diff)
downloadop-kernel-dev-22b8ce94708f7cdf0b04965c6f7443dfd374c35c.zip
op-kernel-dev-22b8ce94708f7cdf0b04965c6f7443dfd374c35c.tar.gz
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.c41
1 files changed, 31 insertions, 10 deletions
diff --git a/kernel/profile.c b/kernel/profile.c
index cd26bed..a9e422d 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)
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