Re: [RFC patch 02/41] LTTng - core data structures

Steven Rostedt
2009-03-06T18:41:23Z

On Thu, 5 Mar 2009, Mathieu Desnoyers wrote:

> Home of the traces data structures. Needs to be built into the kernel.
>
> LTT heartbeat is a module specialized into firing periodical interrupts to
> record events in traces (so cycle counter rollover can be detected) and to
> update the 64 bits "synthetic TSC" (extended from the CPU 32 bits TSC on MIPS).
> Also needs to be built into the kernel.

Why is patch 1 and 2 separate. They look like they should be a single
patch. Patch 1 is pretty useless by itself. This patch depends on patch 1.

-- Steve

>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> ---
> MAINTAINERS | 7 +++
> include/linux/ltt-core.h | 10 ++++
> ltt/ltt-core.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 118 insertions(+)
>
> Index: linux-2.6-lttng/MAINTAINERS
> ===================================================================
> --- linux-2.6-lttng.orig/MAINTAINERS 2009-03-04 13:24:38.000000000 -0500
> +++ linux-2.6-lttng/MAINTAINERS 2009-03-04 13:24:59.000000000 -0500
> @@ -2766,6 +2766,13 @@ P: Eric Piel
> M: eric.piel@tremplin-utc.net
> S: Maintained
>
> +LINUX TRACE TOOLKIT NEXT GENERATION
> +P: Mathieu Desnoyers
> +M: mathieu.desnoyers@polymtl.ca
> +L: ltt-dev@lttng.org
> +W: http://ltt.polymtl.ca
> +S: Maintained
> +
> LM83 HARDWARE MONITOR DRIVER
> P: Jean Delvare
> M: khali@linux-fr.org
> Index: linux-2.6-lttng/ltt/ltt-core.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6-lttng/ltt/ltt-core.c 2009-03-04 13:36:17.000000000 -0500
> @@ -0,0 +1,101 @@
> +/*
> + * LTT core in-kernel infrastructure.
> + *
> + * Copyright 2006 - Mathieu Desnoyers mathieu.desnoyers@polymtl.ca
> + *
> + * Distributed under the GPL license
> + */
> +
> +#include <linux/ltt-core.h>
> +#include <linux/percpu.h>
> +#include <linux/module.h>
> +#include <linux/debugfs.h>
> +#include <linux/kref.h>
> +
> +/* Traces structures */
> +struct ltt_traces ltt_traces = {
> + .setup_head = LIST_HEAD_INIT(ltt_traces.setup_head),
> + .head = LIST_HEAD_INIT(ltt_traces.head),
> +};
> +EXPORT_SYMBOL(ltt_traces);
> +
> +/* Traces list writer locking */
> +static DEFINE_MUTEX(ltt_traces_mutex);
> +
> +/* root dentry mutex */
> +static DEFINE_MUTEX(ltt_root_mutex);
> +/* dentry of ltt's root dir */
> +static struct dentry *ltt_root_dentry;
> +static struct kref ltt_root_kref = {
> + .refcount = ATOMIC_INIT(0),
> +};
> +
> +static void ltt_root_release(struct kref *ref)
> +{
> + debugfs_remove(ltt_root_dentry);
> + ltt_root_dentry = NULL;
> +}
> +
> +void put_ltt_root(void)
> +{
> + mutex_lock(&ltt_root_mutex);
> + if (ltt_root_dentry)
> + kref_put(&ltt_root_kref, ltt_root_release);
> + mutex_unlock(&ltt_root_mutex);
> +}
> +EXPORT_SYMBOL_GPL(put_ltt_root);
> +
> +struct dentry *get_ltt_root(void)
> +{
> + mutex_lock(&ltt_root_mutex);
> + if (!ltt_root_dentry) {
> + ltt_root_dentry = debugfs_create_dir(LTT_ROOT, NULL);
> + if (!ltt_root_dentry) {
> + printk(KERN_ERR "LTT : create ltt root dir failed\n");
> + goto out;
> + }
> + kref_init(&ltt_root_kref);
> + goto out;
> + }
> + kref_get(&ltt_root_kref);
> +out:
> + mutex_unlock(&ltt_root_mutex);
> + return ltt_root_dentry;
> +}
> +EXPORT_SYMBOL_GPL(get_ltt_root);
> +
> +void ltt_lock_traces(void)
> +{
> + mutex_lock(&ltt_traces_mutex);
> +}
> +EXPORT_SYMBOL_GPL(ltt_lock_traces);
> +
> +void ltt_unlock_traces(void)
> +{
> + mutex_unlock(&ltt_traces_mutex);
> +}
> +EXPORT_SYMBOL_GPL(ltt_unlock_traces);
> +
> +DEFINE_PER_CPU(unsigned int, ltt_nesting);
> +EXPORT_PER_CPU_SYMBOL(ltt_nesting);
> +
> +int ltt_run_filter_default(void *trace, uint16_t eID)
> +{
> + return 1;
> +}
> +
> +/* This function pointer is protected by a trace activation check */
> +ltt_run_filter_functor ltt_run_filter = ltt_run_filter_default;
> +EXPORT_SYMBOL_GPL(ltt_run_filter);
> +
> +void ltt_filter_register(ltt_run_filter_functor func)
> +{
> + ltt_run_filter = func;
> +}
> +EXPORT_SYMBOL_GPL(ltt_filter_register);
> +
> +void ltt_filter_unregister(void)
> +{
> + ltt_run_filter = ltt_run_filter_default;
> +}
> +EXPORT_SYMBOL_GPL(ltt_filter_unregister);
>
> --
> Mathieu Desnoyers
> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
>