Messages in this thread | | | Date | Tue, 16 Oct 2018 12:23:22 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf tools: Fix tracing_path_mount proper path |
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Em Tue, Oct 16, 2018 at 12:18:13PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Oct 16, 2018 at 01:48:18PM +0200, Jiri Olsa escreveu: > > If there's no tracefs (RHEL7) support the tracing_path_mount > > returns debugfs path which results in following fail: > > > > # perf probe sys_write > > kprobe_events file does not exist - please rebuild kernel with CONFIG_KPROBE_EVENTS. > > Error: Failed to add events. > > > > In tracing_path_debugfs_mount function we need to return the > > 'tracing' path instead of just the mount to make it work: > > > > # perf probe sys_write > > Added new event: > > probe:sys_write (on sys_write) > > > > You can now use it in all perf tools, such as: > > > > perf record -e probe:sys_write -aR sleep 1 > > > > Adding the 'return tracing_path;' also to tracing_path_tracefs_mount > > function just for consistency with tracing_path_debugfs_mount. > > > > Upstream keeps working, because it has the tracefs support. > > > > Link: http://lkml.kernel.org/n/tip-yiwkzexq9fk1ey1xg3gnjlw4@git.kernel.org > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > --- > > tools/lib/api/fs/tracing_path.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c > > index 120037496f77..5afb11b30fca 100644 > > --- a/tools/lib/api/fs/tracing_path.c > > +++ b/tools/lib/api/fs/tracing_path.c > > @@ -36,7 +36,7 @@ static const char *tracing_path_tracefs_mount(void) > > > > __tracing_path_set("", mnt); > > > > - return mnt; > > + return tracing_path; > > } > > > > static const char *tracing_path_debugfs_mount(void) > > @@ -49,7 +49,7 @@ static const char *tracing_path_debugfs_mount(void) > > > > __tracing_path_set("tracing/", mnt); > > > > - return mnt; > > + return tracing_path; > > Humm, colour me confused, by the name of the function I expected > tracing_path_debugfs_mount() to return the debugfs mount. > > tracing_path_tracefs_mount() would return the tracefs mount point, so, > there, returning tracing_path would be ok. > > Is there some other way to figure out that tracefs isn't available and > thus we should use debugfs_mount + "/tracing/" for the "tracefs" mount? > > This may well be just the naming confusion... lemme read this a bit > more...
Indeed, naming confusion, these are static things, used only by:
const char *tracing_path_mount(void) { const char *mnt;
mnt = tracing_path_tracefs_mount(); if (mnt) return mnt;
mnt = tracing_path_debugfs_mount();
return mnt; }
This one could as well just return tracing_path and the return be used just to figure if it managed to read the mount point for tracefs or debugfs...
Something like:
static int tracing_path_tracefs_mount(void) { const char *mnt = tracefs__mount(); if (!mnt) return -1;
__tracing_path_set("", mnt); return 0; }
static const char *tracing_path_debugfs_mount(void) { const char *mnt = debugfs__mount(); if (!mnt) return -1;
__tracing_path_set("tracing/", mnt); return 0; }
const char *tracing_path_mount(void) { if (tracing_path_tracefs_mount() < 0 && tracing_path_debugfs_mount() < 0) return NULL;
return tracing_path; }
But anyway, your patch fixes things, applying...
- Arnaldo
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