Hi William,
You're right. As you suggest I reverted memory barrier part. Also,
added memory barriers while allocating and freeing memory.
Can you confirm that if it's okay now or missed anything else ?
PS. I couldn't figure out how to reverse function of hotcpu_notifier.
That's why I used register_cpu_notifier and #ifdefs.
On 6/27/05, William Lee Irwin III <[email protected]> wrote:
> On Mon, Jun 27, 2005 at 03:13:13PM +0300, Levent Serinol wrote:
> > +#ifdef CONFIG_SMP
> > +int remove_hash_tables(void)
> > +{
> > + int cpu;
> > +
> > +
> > + for_each_online_cpu(cpu) {
> > + struct page *page;
> > +
> > + if (per_cpu(cpu_profile_hits, cpu)[0]) {
> > + page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
> > + per_cpu(cpu_profile_hits, cpu)[0] = NULL;
> > + __free_page(page);
> > + }
> > + if (per_cpu(cpu_profile_hits, cpu)[1]) {
> > + page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
> > + per_cpu(cpu_profile_hits, cpu)[1] = NULL;
> > + __free_page(page);
> > + }
> > + }
> > + return -1;
>
> Big problem. Timer interrupts can be firing while this is in progress.
> The reason for profile_nop() is so that the code I have running during
> timer interrupts (protected by local_irq_save()) runs to completion,
> where it will afterward discover the flags or variables set to updated
> states. You'll probably have to add more (e.g. memory barriers) since
> you can tolerate less once you're dynamically allocating and freeing etc.
>
>
> On Mon, Jun 27, 2005 at 03:13:13PM +0300, Levent Serinol wrote:
> > @@ -560,7 +668,11 @@ static int __init create_proc_profile(vo
> > return 0;
> > entry->proc_fops = &proc_profile_operations;
> > entry->size = (1+prof_len) * sizeof(atomic_t);
> > - hotcpu_notifier(profile_cpu_callback, 0);
> > +#ifdef CONFIG_HOTPLUG_CPU
> > + register_cpu_notifier(&profile_cpu_notifier);
> > +#endif
> > + profile_params[0] = prof_on;
> > + profile_params[1] = prof_shift;
> > return 0;
> > }
> > module_init(create_proc_profile);
>
> hotcpu_notifier() is there to avoid the #ifdef; you shouldn't need to
> rearrange that.
>
> Anyway, just keep fixing it up. There should be a few more after this.
>
>
> -- wli
>
--
Stay out of the road, if you want to grow old.
~ Pink Floyd ~.
diff -uprN -X dontdiff linux-2.6.12-rc6.orig/include/linux/profile.h linux-2.6.12-rc6/include/linux/profile.h
--- linux-2.6.12-rc6.orig/include/linux/profile.h 2005-03-02 09:38:08.000000000 +0200
+++ linux-2.6.12-rc6/include/linux/profile.h 2005-06-27 10:19:43.000000000 +0300
@@ -6,14 +6,21 @@
#include <linux/kernel.h>
#include <linux/config.h>
#include <linux/init.h>
+#include <linux/sysctl.h>
#include <linux/cpumask.h>
#include <asm/errno.h>
#define CPU_PROFILING 1
#define SCHED_PROFILING 2
+struct ctl_table;
+struct file;
struct proc_dir_entry;
struct pt_regs;
+extern int profile_params[];
+int profile_sysctl_handler(ctl_table *table, int write,
+ struct file *file, void __user *buffer, size_t
+*length, loff_t *ppos);
/* init basic kernel profiler */
void __init profile_init(void);
diff -uprN -X dontdiff linux-2.6.12-rc6.orig/include/linux/sysctl.h linux-2.6.12-rc6/include/linux/sysctl.h
--- linux-2.6.12-rc6.orig/include/linux/sysctl.h 2005-06-27 18:25:13.000000000 +0300
+++ linux-2.6.12-rc6/include/linux/sysctl.h 2005-06-27 10:15:54.000000000 +0300
@@ -136,6 +136,7 @@ enum
KERN_UNKNOWN_NMI_PANIC=66, /* int: unknown nmi panic flag */
KERN_BOOTLOADER_TYPE=67, /* int: boot loader type */
KERN_RANDOMIZE=68, /* int: randomize virtual address space */
+ KERN_PROFILE=69, /* int: profile on/off */
};
diff -uprN -X dontdiff linux-2.6.12-rc6.orig/kernel/profile.c linux-2.6.12-rc6/kernel/profile.c
--- linux-2.6.12-rc6.orig/kernel/profile.c 2005-06-27 18:25:13.000000000 +0300
+++ linux-2.6.12-rc6/kernel/profile.c 2005-06-27 18:23:47.000000000 +0300
@@ -21,7 +21,6 @@
#include <linux/mm.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
-#include <linux/profile.h>
#include <linux/highmem.h>
#include <asm/sections.h>
#include <asm/semaphore.h>
@@ -37,9 +36,12 @@ struct profile_hit {
/* Oprofile timer tick hook */
int (*timer_hook)(struct pt_regs *);
+struct semaphore prof_sem;
+int profile_params[2] = {0, 0};
static atomic_t *prof_buffer;
static unsigned long prof_len, prof_shift;
static int prof_on;
+static int prof_booton;
static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
@@ -74,12 +76,14 @@ __setup("profile=", profile_setup);
void __init profile_init(void)
{
+ init_MUTEX(&prof_sem);
if (!prof_on)
return;
/* only text is profiled */
prof_len = (_etext - _stext) >> prof_shift;
prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t));
+ prof_booton = 1;
}
/* Profile event notifications */
@@ -367,6 +371,12 @@ static int __devinit profile_cpu_callbac
}
return NOTIFY_OK;
}
+static struct notifier_block profile_cpu_notifier =
+{
+ .notifier_call = profile_cpu_callback,
+ .priority = 0,
+};
+
#endif /* CONFIG_HOTPLUG_CPU */
#else /* !CONFIG_SMP */
#define profile_flip_buffers() do { } while (0)
@@ -500,11 +510,11 @@ static struct file_operations proc_profi
};
#ifdef CONFIG_SMP
-static void __init profile_nop(void *unused)
+static void profile_nop(void *unused)
{
}
-static int __init create_hash_tables(void)
+int create_hash_tables(void)
{
int cpu;
@@ -548,6 +558,113 @@ out_cleanup:
#define create_hash_tables() ({ 0; })
#endif
+#ifdef CONFIG_SMP
+int remove_hash_tables(void)
+{
+ int cpu;
+
+
+ prof_on = 0;
+ smp_mb();
+ on_each_cpu(profile_nop, NULL, 0, 1);
+
+ for_each_online_cpu(cpu) {
+ struct page *page;
+
+ if (per_cpu(cpu_profile_hits, cpu)[0]) {
+ page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
+ per_cpu(cpu_profile_hits, cpu)[0] = NULL;
+ __free_page(page);
+ }
+ if (per_cpu(cpu_profile_hits, cpu)[1]) {
+ page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
+ per_cpu(cpu_profile_hits, cpu)[1] = NULL;
+ __free_page(page);
+ }
+ }
+ return -1;
+}
+#else
+#define remove_hash_tables() ({ 0; })
+#endif
+
+int profile_sysctl_handler(ctl_table *table, int write, struct file *file,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ int err;
+ struct proc_dir_entry *entry;
+
+
+ down(&prof_sem);
+
+ if (prof_booton && write)
+ goto out;
+
+ err=proc_dointvec(table, write, file, buffer, length, ppos);
+ if (err < 0 || !write)
+ goto out;
+
+ prof_shift = profile_params[1];
+
+ if (!profile_params[0]) {
+ if (prof_on) {
+ prof_on = 0;
+ remove_proc_entry("profile",NULL);
+#ifdef CONFIG_HOTPLUG_CPU
+ unregister_cpu_notifier(&profile_cpu_notifier);
+#endif
+ remove_hash_tables();
+ smp_mb();
+ on_each_cpu(profile_nop, NULL, 0, 1);
+ vfree(prof_buffer);
+ printk(KERN_INFO "kernel profiling disabled\n");
+ }
+ }
+
+ if ((profile_params[0]==SCHED_PROFILING) || (profile_params[0]==CPU_PROFILING)) {
+ if (prof_on)
+ goto out;
+ prof_len = (_etext - _stext) >> prof_shift;
+ smp_mb();
+ prof_buffer = vmalloc(prof_len*sizeof(atomic_t));
+ if (!prof_buffer)
+ goto out;
+ if (create_hash_tables()) {
+ vfree(prof_buffer);
+ goto out;
+ }
+ prof_on = profile_params[0];
+ if (!(entry = create_proc_entry("profile", S_IWUSR | S_IRUGO, NULL))) {
+ remove_hash_tables();
+ smp_mb();
+ on_each_cpu(profile_nop, NULL, 0, 1);
+ vfree(prof_buffer);
+ goto out;
+ }
+ entry->proc_fops = &proc_profile_operations;
+ entry->size = (1+prof_len) * sizeof(atomic_t);
+#ifdef CONFIG_HOTPLUG_CPU
+ register_cpu_notifier(&profile_cpu_notifier);
+#endif
+ profile_discard_flip_buffers();
+ memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
+ switch(prof_on) {
+ case SCHED_PROFILING:
+ printk(KERN_INFO "kernel schedule profiling enabled (shift: %ld)\n",
+ prof_shift);
+ break;
+ case CPU_PROFILING:
+ printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
+ prof_shift);
+ break;
+ }
+ }
+
+out:
+ up(&prof_sem);
+ return 0;
+}
+
static int __init create_proc_profile(void)
{
struct proc_dir_entry *entry;
@@ -560,7 +677,11 @@ static int __init create_proc_profile(vo
return 0;
entry->proc_fops = &proc_profile_operations;
entry->size = (1+prof_len) * sizeof(atomic_t);
- hotcpu_notifier(profile_cpu_callback, 0);
+#ifdef CONFIG_HOTPLUG_CPU
+ register_cpu_notifier(&profile_cpu_notifier);
+#endif
+ profile_params[0] = prof_on;
+ profile_params[1] = prof_shift;
return 0;
}
module_init(create_proc_profile);
diff -uprN -X dontdiff linux-2.6.12-rc6.orig/kernel/sysctl.c linux-2.6.12-rc6/kernel/sysctl.c
--- linux-2.6.12-rc6.orig/kernel/sysctl.c 2005-06-27 18:25:13.000000000 +0300
+++ linux-2.6.12-rc6/kernel/sysctl.c 2005-06-27 10:19:07.000000000 +0300
@@ -21,6 +21,7 @@
#include <linux/config.h>
#include <linux/module.h>
#include <linux/mm.h>
+#include <linux/profile.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
@@ -642,7 +643,15 @@ static ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
-
+ {
+ .ctl_name = KERN_PROFILE,
+ .procname = "profile",
+ .data = &profile_params,
+ .maxlen = 2*sizeof(int),
+ .mode = 0644,
+ .proc_handler = &profile_sysctl_handler,
+ .strategy = &sysctl_intvec,
+ },
{ .ctl_name = 0 }
};
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