Linux Kernel Markers - Architecture Independent Code Deferred Sync Upon marker probe_unregister, we delay call to synchronize_sched() to accelerate mass unregistration (only when there is no more reference to a give module do we call synchronize_sched()). However, we need to make sure every critical region have ended before we re-arm a marker that has been unregistered and then registered back with a different probe data.
Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]> CC: Christoph Hellwig <[EMAIL PROTECTED]> --- kernel/marker.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) Index: linux-2.6-lttng/kernel/marker.c =================================================================== --- linux-2.6-lttng.orig/kernel/marker.c 2007-07-14 19:38:11.000000000 -0400 +++ linux-2.6-lttng/kernel/marker.c 2007-07-14 19:46:25.000000000 -0400 @@ -30,11 +30,21 @@ extern struct __mark_marker __stop___mar /* * module_mutex nests inside markers_mutex. Markers mutex protects the builtin - * and module markers, and the hash table. + * and module markers, the hash table and deferred_sync. */ DEFINE_MUTEX(markers_mutex); /* + * Marker deferred synchronization. + * Upon marker probe_unregister, we delay call to synchronize_sched() to + * accelerate mass unregistration (only when there is no more reference to a + * give module do we call synchronize_sched()). However, we need to make sure + * every critical region have ended before we re-arm a marker that has been + * unregistered and then registered back with a different probe data. + */ +static int deferred_sync; + +/* * Marker hash table, containing the active markers. * Protected by module_mutex. */ @@ -303,8 +313,10 @@ static inline void __marker_update_probe __stop___markers, probe_module, &refcount); /* Markers in modules. */ __marker_update_probes_modules(probe_module, &refcount); - if (probe_module && refcount == 0) + if (probe_module && refcount == 0) { synchronize_sched(); + deferred_sync = 0; + } } #ifdef CONFIG_MODULES @@ -353,6 +365,10 @@ int marker_probe_register(const char *na ret = -EBUSY; goto end; } + if (deferred_sync) { + synchronize_sched(); + deferred_sync = 0; + } ret = _add_marker(name, format, probe, pdata); if (ret) goto end; @@ -384,6 +400,7 @@ void *marker_probe_unregister(const char /* In what module is the probe handler ? */ probe_module = __module_text_address((unsigned long)entry->probe); pdata = _remove_marker(name); + deferred_sync = 1; _marker_update_probes(probe_module); end: mutex_unlock(&markers_mutex); @@ -425,6 +442,7 @@ iter_end: /* In what module is the probe handler ? */ probe_module = __module_text_address((unsigned long)entry->probe); pdata = _remove_marker(entry->name); + deferred_sync = 1; _marker_update_probes(probe_module); end: mutex_unlock(&markers_mutex); -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/