linux-stable.git/tools/perf/util/dso.c, branch linux-4.2.y

perf tools: Reference count struct dso

2015-06-08T13:31:40+00:00

This has a different model than the 'thread' and 'map' struct lifetimes:
there is not a definitive "don't use this DSO anymore" event, i.e. we may
get many 'struct map' holding references to the '/usr/lib64/libc-2.20.so'
DSO but then at some point some DSO may have no references but we still
don't want to straight away release its resources, because "soon" we may
get a new 'struct map' that needs it and we want to reuse its symtab or
other resources.

So we need some way to garbage collect it when crossing some memory
usage threshold, which is left for anoter patch, for now it is
sufficient to release it when calling dsos__exit(), i.e. when deleting
the whole list as part of deleting the 'struct machine' containing it,
which will leave only referenced objects being used.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/n/tip-majzgz07cm90t2tejrjy4clf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Protect accesses the dso rbtrees/lists with a rw lock

2015-06-08T13:31:40+00:00

To allow concurrent access, next step: refcount struct dso instances, so
that we can ditch unused them when the last map pointing to it goes
away.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/n/tip-yk1k08etpd2aoe3tnrf0oizn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Deal with kernel module names in '[]' correctly

2015-06-03T13:02:38+00:00

Before patch ba92732e9808 ('perf kmaps: Check kmaps to make code more
robust'), 'perf report' and 'perf annotate' will segfault if trace data
contains kernel module information like this:

 # perf report -D -i ./perf.data
 ...
 0 0 0x188 [0x50]: PERF_RECORD_MMAP -1/0: [0xffffffbff1018000(0xf068000) @ 0]: x [test_module]
 ...

 # perf report -i ./perf.data --objdump=/path/to/objdump --kallsyms=/path/to/kallsyms

 perf: Segmentation fault
 -------- backtrace --------
 /path/to/perf[0x503478]
 /lib64/libc.so.6(+0x3545f)[0x7fb201f3745f]
 /path/to/perf[0x499b56]
 /path/to/perf(dso__load_kallsyms+0x13c)[0x49b56c]
 /path/to/perf(dso__load+0x72e)[0x49c21e]
 /path/to/perf(map__load+0x6e)[0x4ae9ee]
 /path/to/perf(thread__find_addr_map+0x24c)[0x47deec]
 /path/to/perf(perf_event__preprocess_sample+0x88)[0x47e238]
 /path/to/perf[0x43ad02]
 /path/to/perf[0x4b55bc]
 /path/to/perf(ordered_events__flush+0xca)[0x4b57ea]
 /path/to/perf[0x4b1a01]
 /path/to/perf(perf_session__process_events+0x3be)[0x4b428e]
 /path/to/perf(cmd_report+0xf11)[0x43bfc1]
 /path/to/perf[0x474702]
 /path/to/perf(main+0x5f5)[0x42de95]
 /lib64/libc.so.6(__libc_start_main+0xf4)[0x7fb201f23bd4]
 /path/to/perf[0x42dfc4]

This is because __kmod_path__parse treats '[' leading names as kernel
name instead of names of kernel module.

If perf.data contains build information and the buildid of such modules
can be found, the dso->kernel of it will be set to DSO_TYPE_KERNEL by
__event_process_build_id(), not kernel module.

It will then be passed to dso__load() -> dso__load_kernel_sym() ->
dso__load_kcore() if --kallsyms is provided.

The refered patch adds NULL pointer checker to avoid segfault. However,
such kernel modules are still processed incorrectly.

This patch fixes __kmod_path__parse, makes it treat names like
'[test_module]' as kernel modules.

kmod-path.c is also update to reflect the above changes.

Signed-off-by: Wang Nan 
Acked-by: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Zefan Li 
Link: http://lkml.kernel.org/r/1433321541-170245-1-git-send-email-wangnan0@huawei.com
[ Fixed the merged with 0443f36b0de0 ("perf machine: Fix the search
  for the kernel DSO on the unified list" ]
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Introduce machine__findnew_dso() method

2015-05-29T15:43:44+00:00

Similar to machine__findnew_thread(), also prepping for refcounting and
locking, this time for struct dso instances.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/n/tip-fv3tshv5o1413coh147lszjc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: No need to have two DSOs lists

2015-05-29T15:43:43+00:00

We can, given a DSO, figure out if it is a kernel, a kernel module or
a userlevel DSO, so stop having to process two lists in several
functions.

If searching becomes an issue at some point, we can have them in a
rbtree, etc.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-s4yb0onpdywu6dj2xl9lxi4t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Adopt findnew_kernel method

2015-05-29T15:43:43+00:00

It never was a 'struct dso' method, so fix that by rename
dso__kernel_findnew() to machine__findnew_kernel().

At some point I'll move it all to the machine.[ch] files, for now
lets ease patch review by not moving too much stuff.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-zrxmblgsg5vx0iv4rhvq2f6l@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add dso__data_get/put_fd()

2015-05-27T15:21:44+00:00

Using dso__data_fd() in multi-thread environment is not safe since
returned fd can be closed and/or reused anytime.

So convert it to the dso__data_get/put_fd() pair to protect the access
with lock.

The original dso__data_fd() is deprecated and kept only for testing.

Signed-off-by: Namhyung Kim 
Acked-by: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1432137821-10853-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Get rid of dso__data_fd() from dso__data_size()

2015-05-27T15:21:44+00:00

It seems that the dso__data_fd() was needed to find a binary type
since open in data_file_size() alone used to fail.

But as it can open the dso fine now, the dso__data_fd() can go away.

Signed-off-by: Namhyung Kim 
Acked-by: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1432137821-10853-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix dso__data_read_offset() file opening

2015-05-27T15:21:44+00:00

When dso__data_read_offset/addr() is called without prior dso__data_fd()
(or other functions which call it internally), it failed to open dso in
data_file_size() since its binary type was not identified.

However calling dso__data_fd() in dso__data_read_offset() will hurt
performance as it grabs a global lock everytime.  So factor out the loop
on the binary type in dso__data_fd(), and call it from both.

Reported-by: Adrian Hunter 
Signed-off-by: Namhyung Kim 
Acked-by: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1432137821-10853-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Protect dso cache fd with a mutex

2015-05-18T13:17:38+00:00

When dso cache is accessed in multi-thread environment, it's possible to
close other dso->data.fd during operation due to open file limit.
Protect the file descriptors using a separate mutex.

Signed-off-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1431909055-21442-28-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo