Commit-ID: 4c0d8d27954d9efb2a02ec9fc16f39b02f248bb7
Gitweb: https://git.kernel.org/tip/4c0d8d27954d9efb2a02ec9fc16f39b02f248bb7
Author: Wang YanQing <udknight@xxxxxxxxx>
AuthorDate: Mon, 15 Jan 2018 13:04:48 +0800
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 23 Jan 2018 09:49:28 -0300
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@xxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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@xxxxxxxxxx>
---
tools/perf/util/dso.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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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