Messages in this thread | | | Date | Mon, 27 Jun 2005 05:56:49 -0700 | From | William Lee Irwin III <> | Subject | Re: [PATCH] enable/disable profiling via proc/sysctl |
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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.
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