Fixing rwtop script race. The issue is caused by rwtop script triggering SIGALRM and underneath pipe reading layer reporting error when interrupted.
Fixing this by setting SA_RESTART for rwtop SIGALRM handler, which avoids interruption of the pipe reading layer. The discussion for this issue & fix is here: https://lkml.org/lkml/2012/9/18/123 Original-patch-by: Andrew Jones <drjo...@redhat.com> Signed-off-by: Jiri Olsa <jo...@redhat.com> Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Ingo Molnar <mi...@elte.hu> Cc: Paul Mackerras <pau...@samba.org> Cc: Corey Ashford <cjash...@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweis...@gmail.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Andrew Jones <drjo...@redhat.com> Cc: David Ahern <dsah...@gmail.com> --- tools/perf/scripts/perl/rwtop.pl | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/scripts/perl/rwtop.pl b/tools/perf/scripts/perl/rwtop.pl index 4bb3ecd..8b20787 100644 --- a/tools/perf/scripts/perl/rwtop.pl +++ b/tools/perf/scripts/perl/rwtop.pl @@ -17,6 +17,7 @@ use lib "$ENV{'PERF_EXEC_PATH'}/scripts/perl/Perf-Trace-Util/lib"; use lib "./Perf-Trace-Util/lib"; use Perf::Trace::Core; use Perf::Trace::Util; +use POSIX qw/SIGALRM SA_RESTART/; my $default_interval = 3; my $nlines = 20; @@ -90,7 +91,10 @@ sub syscalls::sys_enter_write sub trace_begin { - $SIG{ALRM} = \&set_print_pending; + my $sa = POSIX::SigAction->new(\&set_print_pending); + $sa->flags(SA_RESTART); + $sa->safe(1); + POSIX::sigaction(SIGALRM, $sa) or die "Can't set SIGALRM handler: $!\n"; alarm 1; } -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
