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authorNelson Elhage <nelhage@nelhage.com>2011-12-19 08:39:32 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2011-12-23 16:53:58 -0200
commit41d0d933494ce10eb77758a1168b08e317c42e8e (patch)
treef907773714846b5b5cf85b4f450bb6fe07b168d4 /tools/perf/builtin-record.c
parent18e6093904abfd51671ff5846c2fdaba9ebbf21b (diff)
downloadlinux-linaro-stable-41d0d933494ce10eb77758a1168b08e317c42e8e.tar.gz
perf: builtin-record: Document and check that mmap_pages must be a power of two.
Now that we automatically point users at it, let's provide them some guidance so that they hopefully don't just get mysterious EINVAL's from the kernel. Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1324301972-22740-4-git-send-email-nelhage@nelhage.com Signed-off-by: Nelson Elhage <nelhage@nelhage.com> [ committer note: Made it work after 50a682c ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-record.c')
-rw-r--r--tools/perf/builtin-record.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 56bb4476e3ba..e873ae2dd54c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -279,6 +279,9 @@ try_again:
"/proc/sys/kernel/perf_event_mlock_kb,\n"
"or try again with a smaller value of -m/--mmap_pages.\n"
"(current value: %d)\n", opts->mmap_pages);
+ else if (!is_power_of_2(opts->mmap_pages))
+ die("--mmap_pages/-m value must be a power of two.");
+
die("failed to mmap with %d (%s)\n", errno, strerror(errno));
}