Re: [PATCH perf/core v10 10/23] perf probe: Remove caches when --cache is given

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Jun 08, 2016 at 06:30:40PM +0900, Masami Hiramatsu escreveu:
> From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> 
> perf-probe --del removes caches when --cache is given.
> Note that the delete pattern is not same as normal events.
> 
> If you cached probes with event name, --del "eventname"
> works as expected. However, if you skipped it, the cached
> probes doesn't have actual event name. In that case
>  --del "probe-desc" is required (wildcard is acceptable).
> For example a cache entry has the probe-desc "vfs_read $params",
> you can remove it with --del 'vfs_read*'.
> 
>   -----
>   # perf probe --cache --list
>   /[kernel.kallsyms] (1466a0a250b5d0070c6d0f03c5fed30b237970a1):
>   vfs_read $params
>   /usr/lib64/libc-2.17.so (c31ffe7942bfd77b2fca8f9bd5709d387a86d3bc):
>   getaddrinfo $params
> 
>   # perf probe --cache --del vfs_read\*
>   Removed cached event: probe:vfs_read
> 
>   # perf probe --cache --list
>   /[kernel.kallsyms] (1466a0a250b5d0070c6d0f03c5fed30b237970a1):
>   /usr/lib64/libc-2.17.so (c31ffe7942bfd77b2fca8f9bd5709d387a86d3bc):
>   getaddrinfo $params
>   -----
> 
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
>  Changes in v9:
>   - Fix to show which event is deleted (Thanks Hemant!)
>  Changes in v4:
>   - move del_perf_probe_caches() into builtin-probe.c since
>     command-line related delete procedure is there now.
> ---
>  tools/perf/Documentation/perf-probe.txt |    1 +
>  tools/perf/builtin-probe.c              |   27 +++++++++++++++++++++++++
>  tools/perf/util/probe-file.c            |   34 +++++++++++++++++++++++++------
>  tools/perf/util/probe-file.h            |    2 ++
>  4 files changed, 57 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
> index 5a70d45..8d09173 100644
> --- a/tools/perf/Documentation/perf-probe.txt
> +++ b/tools/perf/Documentation/perf-probe.txt
> @@ -116,6 +116,7 @@ OPTIONS
>  	(With --add) Cache the probes. Any events which successfully added
>  	are also stored in the cache file.
>  	(With --list) Show cached probes.
> +	(With --del) Remove cached probes.
>  
>  --max-probes=NUM::
>  	Set the maximum number of probe points for an event. Default is 128.
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index 53e380c0e..8f61525 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -363,6 +363,30 @@ out_cleanup:
>  	return ret;
>  }
>  
> +static int del_perf_probe_caches(struct strfilter *filter)
> +{
> +	struct probe_cache *cache;
> +	struct strlist *bidlist;
> +	struct str_node *nd;
> +	int ret;
> +
> +	ret = build_id_cache__list_all(&bidlist);
> +	if (ret < 0) {
> +		pr_debug("Failed to get buildids: %d\n", ret);
> +		return ret;
> +	}
> +
> +	strlist__for_each(nd, bidlist) {
> +		cache = probe_cache__new(nd->s);
> +		if (!cache)
> +			continue;
> +		probe_cache__remove_entries(cache, filter);
> +		probe_cache__commit(cache);



> +		probe_cache__delete(cache);
> +	}
> +	return 0;
> +}
> +
>  static int perf_del_probe_events(struct strfilter *filter)
>  {
>  	int ret, ret2, ufd = -1, kfd = -1;
> @@ -375,6 +399,9 @@ static int perf_del_probe_events(struct strfilter *filter)
>  
>  	pr_debug("Delete filter: \'%s\'\n", str);
>  
> +	if (probe_conf.cache)
> +		return del_perf_probe_caches(filter);
> +
>  	/* Get current event names */
>  	ret = probe_file__open_both(&kfd, &ufd, PF_FL_RW);
>  	if (ret < 0)
> diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
> index a6d4a67..f687607 100644
> --- a/tools/perf/util/probe-file.c
> +++ b/tools/perf/util/probe-file.c
> @@ -660,19 +660,39 @@ out:
>  	return ret;
>  }
>  
> +static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
> +				       struct strfilter *filter)
> +{
> +	char buf[128], *ptr = entry->spev;
> +
> +	if (entry->pev.event) {
> +		snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
> +		ptr = buf;
> +	}
> +	return strfilter__compare(filter, ptr);
> +}
> +
> +int probe_cache__remove_entries(struct probe_cache *pcache,
> +				struct strfilter *filter)
> +{
> +	struct probe_cache_entry *entry, *tmp;
> +
> +	list_for_each_entry_safe(entry, tmp, &pcache->list, list) {

so here you used the preferred idiom, i.e. using
list_for_each_entry_safe(), once you stop doing the list removal at the
list entry destructor, it gets the good old boring usual idiom, please
do that.

Also please consider renaming perf_cache__remove_entries() to
perf_cache__filter_purge(), as it doesn't simply remove entries, it
purges them (that is, remove an entry and delete it), and only if the
entry got filtered.

> +		if (probe_cache_entry__compare(entry, filter)) {
> +			pr_info("Removed cached event: %s\n", entry->spev);
> +			probe_cache_entry__delete(entry);
> +		}
> +	}
> +	return 0;
> +}
> +
>  static int probe_cache__show_entries(struct probe_cache *pcache,
>  				     struct strfilter *filter)
>  {
>  	struct probe_cache_entry *entry;
> -	char buf[128], *ptr;
>  
>  	list_for_each_entry(entry, &pcache->list, list) {
> -		if (entry->pev.event) {
> -			ptr = buf;
> -			snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
> -		} else
> -			ptr = entry->spev;
> -		if (strfilter__compare(filter, ptr))
> +		if (probe_cache_entry__compare(entry, filter))
>  			printf("%s\n", entry->spev);
>  	}
>  	return 0;
> diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
> index ac70446..e6fd9b9 100644
> --- a/tools/perf/util/probe-file.h
> +++ b/tools/perf/util/probe-file.h
> @@ -37,6 +37,8 @@ int probe_cache__add_entry(struct probe_cache *pcache,
>  			   struct probe_trace_event *tevs, int ntevs);
>  int probe_cache__commit(struct probe_cache *pcache);
>  void probe_cache__delete(struct probe_cache *pcache);
> +int probe_cache__remove_entries(struct probe_cache *pcache,
> +				struct strfilter *filter);
>  struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
>  					    struct perf_probe_event *pev);
>  struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,