Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262450AbUKDWEz (ORCPT ); Thu, 4 Nov 2004 17:04:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262472AbUKDWCI (ORCPT ); Thu, 4 Nov 2004 17:02:08 -0500 Received: from omx3-ext.sgi.com ([192.48.171.20]:19653 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S262446AbUKDVzn (ORCPT ); Thu, 4 Nov 2004 16:55:43 -0500 From: Jesse Barnes To: William Lee Irwin III Subject: Re: contention on profile_lock Date: Thu, 4 Nov 2004 13:55:27 -0800 User-Agent: KMail/1.7 Cc: Jack Steiner , linux-kernel@vger.kernel.org, edwardsg@sgi.com, dipankar@in.ibm.com, levon@movementarian.org References: <200411021152.16038.jbarnes@engr.sgi.com> <20041104201257.GA14786@holomorphy.com> <200411041249.21718.jbarnes@engr.sgi.com> In-Reply-To: <200411041249.21718.jbarnes@engr.sgi.com> MIME-Version: 1.0 Content-Type: Multipart/Mixed; boundary="Boundary-00=_PVqiBv6S+eG5gdA" Message-Id: <200411041355.27228.jbarnes@engr.sgi.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4814 Lines: 175 --Boundary-00=_PVqiBv6S+eG5gdA Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Thursday, November 4, 2004 12:49 pm, Jesse Barnes wrote: > John pointed out that this breaks modules. Would registering and > unregistering a function pointer thus be module safe? Dipankar, hopefully > you have something better? > > static int timer_start(void) > { > /* Setup the callback pointer */ > oprofile_timer_notify = oprofile_timer; > return 0; > } > > > static void timer_stop(void) > { > /* Tear down the callback pointer after sync_kernel */ > synchronize_kernel(); > oprofile_timer_notify = NULL; > } Ok, here's another one that uses this approach. Hopefully it satisfies all parties? (Compile tested only so far.) Thanks, Jesse --Boundary-00=_PVqiBv6S+eG5gdA Content-Type: text/plain; charset="iso-8859-1"; name="remove-profile-notifier-list-3.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="remove-profile-notifier-list-3.patch" ===== drivers/oprofile/timer_int.c 1.8 vs edited ===== --- 1.8/drivers/oprofile/timer_int.c 2004-09-03 16:55:27 -07:00 +++ edited/drivers/oprofile/timer_int.c 2004-11-04 13:54:13 -08:00 @@ -13,33 +13,31 @@ #include #include #include +#include #include -static int timer_notify(struct notifier_block * self, unsigned long val, void * data) +static int timer_notify(struct pt_regs *regs) { - struct pt_regs * regs = (struct pt_regs *)data; int cpu = smp_processor_id(); unsigned long eip = profile_pc(regs); oprofile_add_sample(eip, !user_mode(regs), 0, cpu); return 0; } - - -static struct notifier_block timer_notifier = { - .notifier_call = timer_notify, -}; - static int timer_start(void) { - return register_profile_notifier(&timer_notifier); + /* Setup the callback pointer */ + oprofile_timer_notify = timer_notify; + return 0; } static void timer_stop(void) { - unregister_profile_notifier(&timer_notifier); + /* Tear down the callback pointer after sync_kernel */ + synchronize_kernel(); + oprofile_timer_notify = NULL; } ===== include/linux/oprofile.h 1.10 vs edited ===== --- 1.10/include/linux/oprofile.h 2004-06-24 01:56:02 -07:00 +++ edited/include/linux/oprofile.h 2004-11-04 13:54:04 -08:00 @@ -105,5 +105,8 @@ /** lock for read/write safety */ extern spinlock_t oprofilefs_lock; + +/* Timer based profiling hook */ +extern int (*oprofile_timer_notify)(struct pt_regs *); #endif /* OPROFILE_H */ ===== kernel/profile.c 1.14 vs edited ===== --- 1.14/kernel/profile.c 2004-10-19 02:40:31 -07:00 +++ edited/kernel/profile.c 2004-11-04 13:50:36 -08:00 @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -34,6 +35,9 @@ #define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit)) #define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ) +/* Oprofile timer tick hook */ +int (*oprofile_timer_notify)(struct pt_regs *); + static atomic_t *prof_buffer; static unsigned long prof_len, prof_shift; static int prof_on; @@ -168,38 +172,6 @@ return err; } -static struct notifier_block * profile_listeners; -static rwlock_t profile_lock = RW_LOCK_UNLOCKED; - -int register_profile_notifier(struct notifier_block * nb) -{ - int err; - write_lock_irq(&profile_lock); - err = notifier_chain_register(&profile_listeners, nb); - write_unlock_irq(&profile_lock); - return err; -} - - -int unregister_profile_notifier(struct notifier_block * nb) -{ - int err; - write_lock_irq(&profile_lock); - err = notifier_chain_unregister(&profile_listeners, nb); - write_unlock_irq(&profile_lock); - return err; -} - - -void profile_hook(struct pt_regs * regs) -{ - read_lock(&profile_lock); - notifier_call_chain(&profile_listeners, 0, regs); - read_unlock(&profile_lock); -} - -EXPORT_SYMBOL_GPL(register_profile_notifier); -EXPORT_SYMBOL_GPL(unregister_profile_notifier); EXPORT_SYMBOL_GPL(task_handoff_register); EXPORT_SYMBOL_GPL(task_handoff_unregister); @@ -394,8 +366,8 @@ void profile_tick(int type, struct pt_regs *regs) { - if (type == CPU_PROFILING) - profile_hook(regs); + if (type == CPU_PROFILING && oprofile_timer_notify) + oprofile_timer_notify(regs); if (!user_mode(regs) && cpu_isset(smp_processor_id(), prof_cpu_mask)) profile_hit(type, (void *)profile_pc(regs)); } --Boundary-00=_PVqiBv6S+eG5gdA-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/