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authorWang YanQing <udknight@gmail.com>2018-01-15 13:04:48 +0800
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-01-23 09:49:28 -0300
commit4c0d8d27954d9efb2a02ec9fc16f39b02f248bb7 (patch)
tree644129db3a29b75544c6b4fe99ff8b0f52b2b4ed /tools/perf
parent5c61d70e55ab1cb917752f4a0d5f4683b4869e32 (diff)
downloadop-kernel-dev-4c0d8d27954d9efb2a02ec9fc16f39b02f248bb7.zip
op-kernel-dev-4c0d8d27954d9efb2a02ec9fc16f39b02f248bb7.tar.gz
perf symbols: Using O_CLOEXEC in do_open
I've meet a strange behavior with these commands on my gentoo box: 1: perf kmem record 2: CTRL-C to stop 1 3: perf report 4: "Enter", "Enter", "Run scripts for all samples", "event_analyzing_sample". Then 'perf report' says: " No kallsyms or vmlinux with build-id xxxx was found /lib/modules/4.10.0+/build/vmlinux with build id xxxx not found, continuing without symbols ". It is strange because I am sure /lib/modules/4.10.0+/build/vmlinux is right for perf.data. After digging, I found out the reason is that "perf report" generates many open fds, then "script_browse" uses popen to run "perf script" which run out of open files. The gentoo box has a small default value for "max open files", 1024. Yes, "ulimit -n " with a bigger number could fix it, but I think that using O_CLOEXEC in do_open is a better way. Signed-off-by: Wang YanQing <udknight@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180115050448.GA20759@udknight [ Make sure O_CLOEXEC is available in old systems by adding a patch just before this one, to keep this bisectable in such systems ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/dso.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index d5b6f7f..36ef45b 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -446,7 +446,7 @@ static int do_open(char *name)
char sbuf[STRERR_BUFSIZE];
do {
- fd = open(name, O_RDONLY);
+ fd = open(name, O_RDONLY|O_CLOEXEC);
if (fd >= 0)
return fd;
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