| Message ID | 20190114152800.31060-4-kaslevs@vmware.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add VM kernel tracing over vsock sockets | expand |
On Mon, 14 Jan 2019 17:27:57 +0200 Slavomir Kaslev <kaslevs@vmware.com> wrote: > @@ -194,8 +196,9 @@ tracecmd_create_buffer_recorder_fd(int fd, int cpu, unsigned flags, const char * > return tracecmd_create_buffer_recorder_fd2(fd, -1, cpu, flags, buffer, 0); > } > > -struct tracecmd_recorder * > -tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, const char *buffer) > +static struct tracecmd_recorder * > +__tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, > + const char *buffer) > { > struct tracecmd_recorder *recorder; > int fd; > @@ -258,6 +261,26 @@ tracecmd_create_buffer_recorder_maxkb(const char *file, int cpu, unsigned flags, > goto out; > } > > +struct tracecmd_recorder * > +tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, > + const char *buffer) > +{ > + return __tracecmd_create_buffer_recorder(file, cpu, flags, buffer); > +} > + > +struct tracecmd_recorder * > +tracecmd_create_recorder_virt(const char *file, int cpu, int trace_fd) As this looks to be something that may be a library call someday, I would keep flags as a parameter. > +{ > + struct tracecmd_recorder *recorder; > + > + recorder = __tracecmd_create_buffer_recorder( > + file, cpu, TRACECMD_RECORD_NOSPLICE, NULL); Then you could pass this as: recorder = __tracecmd_create_buffer_recorder(file, cpu, flags | TRACECMD_RECORD_NOSPLICE, NULL); -- Steve > + if (recorder) > + recorder->trace_fd = trace_fd; > + > + return recorder; > +} > + > struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu, unsigned flags) > { > const char *tracing;
On Tue, Jan 15, 2019 at 12:12 AM Steven Rostedt <rostedt@goodmis.org> wrote: > > On Mon, 14 Jan 2019 17:27:57 +0200 > Slavomir Kaslev <kaslevs@vmware.com> wrote: > > > > @@ -194,8 +196,9 @@ tracecmd_create_buffer_recorder_fd(int fd, int cpu, unsigned flags, const char * > > return tracecmd_create_buffer_recorder_fd2(fd, -1, cpu, flags, buffer, 0); > > } > > > > -struct tracecmd_recorder * > > -tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, const char *buffer) > > +static struct tracecmd_recorder * > > +__tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, > > + const char *buffer) > > { > > struct tracecmd_recorder *recorder; > > int fd; > > @@ -258,6 +261,26 @@ tracecmd_create_buffer_recorder_maxkb(const char *file, int cpu, unsigned flags, > > goto out; > > } > > > > +struct tracecmd_recorder * > > +tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, > > + const char *buffer) > > +{ > > + return __tracecmd_create_buffer_recorder(file, cpu, flags, buffer); > > +} > > + > > +struct tracecmd_recorder * > > +tracecmd_create_recorder_virt(const char *file, int cpu, int trace_fd) > > As this looks to be something that may be a library call someday, I > would keep flags as a parameter. > > > +{ > > + struct tracecmd_recorder *recorder; > > + > > + recorder = __tracecmd_create_buffer_recorder( > > + file, cpu, TRACECMD_RECORD_NOSPLICE, NULL); > > Then you could pass this as: > > recorder = __tracecmd_create_buffer_recorder(file, cpu, > flags | TRACECMD_RECORD_NOSPLICE, NULL); > Makes sense but (continues below) > -- Steve > > > + if (recorder) > > + recorder->trace_fd = trace_fd; it's this part that cannot be done outside of trace-recorder.c since `recorder->trace_fd` is not exposed. `tracecmd_create_recorder_virt` just allows a user to provide his own file descriptor from where tracing data should be read (in this case from the agent's vsock sockets) On an unrelated note, the TRACECMD_RECORD_NOSPLICE flag is only needed on Linux version <4.20. Do we want to detect if splicing on vsock sockets works on startup and use this flag only if necessary? > > + > > + return recorder; > > +} > > + > > struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu, unsigned flags) > > { > > const char *tracing; >
On Tue, 15 Jan 2019 14:21:11 +0000 Slavomir Kaslev <kaslevs@vmware.com> wrote: > On an unrelated note, the TRACECMD_RECORD_NOSPLICE flag is only needed > on Linux version <4.20. Do we want to detect if splicing on vsock > sockets works on startup and use this flag only if necessary? Yes, sounds reasonable. -- Steve
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h index 99a455c..f0747c5 100644 --- a/include/trace-cmd/trace-cmd.h +++ b/include/trace-cmd/trace-cmd.h @@ -277,6 +277,7 @@ enum { void tracecmd_free_recorder(struct tracecmd_recorder *recorder); struct tracecmd_recorder *tracecmd_create_recorder(const char *file, int cpu, unsigned flags); struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu, unsigned flags); +struct tracecmd_recorder *tracecmd_create_recorder_virt(const char *file, int cpu, int trace_fd); struct tracecmd_recorder *tracecmd_create_recorder_maxkb(const char *file, int cpu, unsigned flags, int maxkb); struct tracecmd_recorder *tracecmd_create_buffer_recorder_fd(int fd, int cpu, unsigned flags, const char *buffer); struct tracecmd_recorder *tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, const char *buffer); diff --git a/lib/trace-cmd/trace-recorder.c b/lib/trace-cmd/trace-recorder.c index 5331925..497f752 100644 --- a/lib/trace-cmd/trace-recorder.c +++ b/lib/trace-cmd/trace-recorder.c @@ -148,16 +148,22 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags, recorder->fd1 = fd; recorder->fd2 = fd2; - if (flags & TRACECMD_RECORD_SNAPSHOT) - ret = asprintf(&path, "%s/per_cpu/cpu%d/snapshot_raw", buffer, cpu); - else - ret = asprintf(&path, "%s/per_cpu/cpu%d/trace_pipe_raw", buffer, cpu); - if (ret < 0) - goto out_free; + if (buffer) { + if (flags & TRACECMD_RECORD_SNAPSHOT) + ret = asprintf(&path, "%s/per_cpu/cpu%d/snapshot_raw", + buffer, cpu); + else + ret = asprintf(&path, "%s/per_cpu/cpu%d/trace_pipe_raw", + buffer, cpu); + if (ret < 0) + goto out_free; + + recorder->trace_fd = open(path, O_RDONLY); + free(path); - recorder->trace_fd = open(path, O_RDONLY); - if (recorder->trace_fd < 0) - goto out_free; + if (recorder->trace_fd < 0) + goto out_free; + } if ((recorder->flags & TRACECMD_RECORD_NOSPLICE) == 0) { ret = pipe(recorder->brass); @@ -177,13 +183,9 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags, recorder->pipe_size = pipe_size; } - free(path); - return recorder; out_free: - free(path); - tracecmd_free_recorder(recorder); return NULL; } @@ -194,8 +196,9 @@ tracecmd_create_buffer_recorder_fd(int fd, int cpu, unsigned flags, const char * return tracecmd_create_buffer_recorder_fd2(fd, -1, cpu, flags, buffer, 0); } -struct tracecmd_recorder * -tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, const char *buffer) +static struct tracecmd_recorder * +__tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, + const char *buffer) { struct tracecmd_recorder *recorder; int fd; @@ -258,6 +261,26 @@ tracecmd_create_buffer_recorder_maxkb(const char *file, int cpu, unsigned flags, goto out; } +struct tracecmd_recorder * +tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags, + const char *buffer) +{ + return __tracecmd_create_buffer_recorder(file, cpu, flags, buffer); +} + +struct tracecmd_recorder * +tracecmd_create_recorder_virt(const char *file, int cpu, int trace_fd) +{ + struct tracecmd_recorder *recorder; + + recorder = __tracecmd_create_buffer_recorder( + file, cpu, TRACECMD_RECORD_NOSPLICE, NULL); + if (recorder) + recorder->trace_fd = trace_fd; + + return recorder; +} + struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu, unsigned flags) { const char *tracing;
Add tracecmd_create_recorder_virt function that will be used for tracing VM guests. Signed-off-by: Slavomir Kaslev <kaslevs@vmware.com> --- include/trace-cmd/trace-cmd.h | 1 + lib/trace-cmd/trace-recorder.c | 53 ++++++++++++++++++++++++---------- 2 files changed, 39 insertions(+), 15 deletions(-)