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perf record: Fix fast task-exit race 

Recording with -a (or with -p) can race with tasks going away:

   couldn't open /proc/8440/maps

Causing an early exit() and no recording done.

Do not abort the recording session - instead just skip that task.

Also, only print the warnings under -v.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-06-15 08:17:12 +02:00
parent 038e836e97
commit 613d860229
1 changed files with 12 additions and 4 deletions
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16
tools/perf/builtin-record.c
View File

@ -202,8 +202,12 @@ static void pid_synthesize_comm_event(pid_t pid, int full)
fd = open(filename, O_RDONLY); fd = open(filename, O_RDONLY);
if (fd < 0) { if (fd < 0) {
fprintf(stderr, "couldn't open %s\n", filename); /*
exit(EXIT_FAILURE); * We raced with a task exiting - just return:
*/
if (verbose)
fprintf(stderr, "couldn't open %s\n", filename);
return;
} }
if (read(fd, bf, sizeof(bf)) < 0) { if (read(fd, bf, sizeof(bf)) < 0) {
fprintf(stderr, "couldn't read %s\n", filename); fprintf(stderr, "couldn't read %s\n", filename);
@ -273,8 +277,12 @@ static void pid_synthesize_mmap_samples(pid_t pid)
fp = fopen(filename, "r"); fp = fopen(filename, "r");
if (fp == NULL) { if (fp == NULL) {
fprintf(stderr, "couldn't open %s\n", filename); /*
exit(EXIT_FAILURE); * We raced with a task exiting - just return:
*/
if (verbose)
fprintf(stderr, "couldn't open %s\n", filename);
return;
} }
while (1) { while (1) {
char bf[BUFSIZ], *pbf = bf; char bf[BUFSIZ], *pbf = bf;