[igt-dev] [PATCH i-g-t v19 04/34] lib/igt_core: Track child process pid and tid
Zbigniew Kempczyński
zbigniew.kempczynski at intel.com
Tue Feb 2 09:24:13 UTC 2021
Introduce variables which can decrease number of getpid()/gettid()
calls, especially for allocator which must be aware of method
acquiring addresses.
When child is spawned using igt_fork() we can control its initialization
and prepare child_pid implicitly. Tracking child_tid requires our
intervention in the code and do something like this:
if (child_tid == -1)
child_tid = gettid()
Variable was created for using in TLS so each thread is created
with variable set to -1. This will give each thread it's own "copy"
and there's no risk to use other thread tid. For each forked child
we reassign -1 to child_tid to avoid using already set variable.
Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
Cc: Dominik Grzegorzek <dominik.grzegorzek at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala at intel.com>
Acked-by: Arjun Melkaveri <arjun.melkaveri at intel.com>
---
lib/igt_core.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/igt_core.c b/lib/igt_core.c
index f9dfaa0dd..2b4182f16 100644
--- a/lib/igt_core.c
+++ b/lib/igt_core.c
@@ -306,6 +306,10 @@ int num_test_children;
int test_children_sz;
bool test_child;
+/* For allocator purposes */
+pid_t child_pid = -1;
+__thread pid_t child_tid = -1;
+
enum {
/*
* Let the first values be used by individual tests so options don't
@@ -2302,6 +2306,8 @@ bool __igt_fork(void)
case 0:
test_child = true;
pthread_mutex_init(&print_mutex, NULL);
+ child_pid = getpid();
+ child_tid = -1;
exit_handler_count = 0;
reset_helper_process_list();
oom_adjust_for_doom();
--
2.26.0
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