From fb40bd78b0f91b274879cf5db8facd1e04b6052e Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Wed, 13 Feb 2008 15:03:37 -0800 Subject: Linux Kernel Markers: support multiple probes RCU style multiple probes support for the Linux Kernel Markers. Common case (one probe) is still fast and does not require dynamic allocation or a supplementary pointer dereference on the fast path. - Move preempt disable from the marker site to the callback. Since we now have an internal callback, move the preempt disable/enable to the callback instead of the marker site. Since the callback change is done asynchronously (passing from a handler that supports arguments to a handler that does not setup the arguments is no arguments are passed), we can safely update it even if it is outside the preempt disable section. - Move probe arm to probe connection. Now, a connected probe is automatically armed. Remove MARK_MAX_FORMAT_LEN, unused. This patch modifies the Linux Kernel Markers API : it removes the probe "arm/disarm" and changes the probe function prototype : it now expects a va_list * instead of a "...". If we want to have more than one probe connected to a marker at a given time (LTTng, or blktrace, ssytemtap) then we need this patch. Without it, connecting a second probe handler to a marker will fail. It allow us, for instance, to do interesting combinations : Do standard tracing with LTTng and, eventually, to compute statistics with SystemTAP, or to have a special trigger on an event that would call a systemtap script which would stop flight recorder tracing. Signed-off-by: Mathieu Desnoyers Cc: Christoph Hellwig Cc: Mike Mason Cc: Dipankar Sarma Cc: David Smith Cc: "Paul E. McKenney" Cc: "Frank Ch. Eigler" Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/platforms/cell/spufs/sputrace.c | 31 ++++++++++------------------ 1 file changed, 11 insertions(+), 20 deletions(-) (limited to 'arch') diff --git a/arch/powerpc/platforms/cell/spufs/sputrace.c b/arch/powerpc/platforms/cell/spufs/sputrace.c index 2b1953f6f12..01974f7776e 100644 --- a/arch/powerpc/platforms/cell/spufs/sputrace.c +++ b/arch/powerpc/platforms/cell/spufs/sputrace.c @@ -146,34 +146,28 @@ static void sputrace_log_item(const char *name, struct spu_context *ctx, wake_up(&sputrace_wait); } -static void spu_context_event(const struct marker *mdata, - void *private, const char *format, ...) +static void spu_context_event(void *probe_private, void *call_data, + const char *format, va_list *args) { - struct spu_probe *p = mdata->private; - va_list ap; + struct spu_probe *p = probe_private; struct spu_context *ctx; struct spu *spu; - va_start(ap, format); - ctx = va_arg(ap, struct spu_context *); - spu = va_arg(ap, struct spu *); + ctx = va_arg(*args, struct spu_context *); + spu = va_arg(*args, struct spu *); sputrace_log_item(p->name, ctx, spu); - va_end(ap); } -static void spu_context_nospu_event(const struct marker *mdata, - void *private, const char *format, ...) +static void spu_context_nospu_event(void *probe_private, void *call_data, + const char *format, va_list *args) { - struct spu_probe *p = mdata->private; - va_list ap; + struct spu_probe *p = probe_private; struct spu_context *ctx; - va_start(ap, format); - ctx = va_arg(ap, struct spu_context *); + ctx = va_arg(*args, struct spu_context *); sputrace_log_item(p->name, ctx, NULL); - va_end(ap); } struct spu_probe spu_probes[] = { @@ -219,10 +213,6 @@ static int __init sputrace_init(void) if (error) printk(KERN_INFO "Unable to register probe %s\n", p->name); - - error = marker_arm(p->name); - if (error) - printk(KERN_INFO "Unable to arm probe %s\n", p->name); } return 0; @@ -238,7 +228,8 @@ static void __exit sputrace_exit(void) int i; for (i = 0; i < ARRAY_SIZE(spu_probes); i++) - marker_probe_unregister(spu_probes[i].name); + marker_probe_unregister(spu_probes[i].name, + spu_probes[i].probe_func, &spu_probes[i]); remove_proc_entry("sputrace", NULL); kfree(sputrace_log); -- cgit v1.2.3