tree f816efa6ebb791f3bac6bed9843a405c6729cff1
parent 5b4398209d646635a4d84c46a5c7193fbce1a07c
author Don Zickus <dzickus@redhat.com> 1393429526 -0500
committer Arnaldo Carvalho de Melo <acme@redhat.com> 1394806844 -0300

perf tools: Fix synthesizing mmaps for threads

Currently if a process creates a bunch of threads using pthread_create
and then perf is run in system_wide mode, the mmaps for those threads
are not captured with a synthesized mmap event.

The reason is those threads are not visible when walking the /proc/
directory looking for /proc/<pid>/maps files.  Instead they are
discovered using the /proc/<pid>/tasks file (which the synthesized comm
event uses).

This causes problems when a program is trying to map a data address to a
tid.  Because the tid has no maps, the event is dropped.  Changing the
program to look up using the pid instead of the tid, finds the correct
maps but creates ugly hacks in the program to carry the correct tid
around.

Fix this by moving the walking of the /proc/<pid>/tasks up a level (out
of the comm function) based on Arnaldo's suggestion.

Tweaked things a bit to special case the 'full' bit and 'guest' check.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1393429527-167840-2-git-send-email-dzickus@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>