From: Don Zickus <dzickus@redhat.com>
Date: Thu, 21 Aug 2014 03:25:11 +0000 (-0400)
Subject: perf machine: Fallback to MAP__FUNCTION if daddr maps are NULL
X-Git-Tag: omap-for-v3.19/prcm-cleanup~97^2~27^2~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=06b2afc0b9a26e7673856a24ab57bfb307dad394;p=pandora-kernel.git

perf machine: Fallback to MAP__FUNCTION if daddr maps are NULL

As we run "perf c2c" on more applications, we noticed we're missing
significant samples from a common customer's application.  Looking at
the /proc/<pid>/maps file for the app, we see "rwxs" and "rwxp"
permissions on many of the shared memory & heap regions, and on all the
thread stacks.

Because those regions have the "x" bit set, perf marks them with a
MAP_FUNCTION type.  Hence ip_resolve_data() never finds load or store
events coming from them.

We fixed this by re-calling thread__find_addr_location with
MAP__FUNCTION in the case where map is NULL as a last ditch effort to
map the sample before giving up and dropping it.

Reported-by: Joe Mario <jmario@redhat.com>
Tested-by: Joe Mario <jmario@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1408591511-57884-1-git-send-email-dzickus@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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