On 2024/11/27 11:21, Jiri Olsa wrote:
On Tue, Nov 26, 2024 at 10:24:07PM +0000, Juntong Deng wrote:
On 2024/11/20 11:27, Jiri Olsa wrote:
On Tue, Nov 19, 2024 at 05:53:59PM +0000, Juntong Deng wrote:
SNIP
+static void subtest_task_file_iters(void)
+{
+ int prog_fd, child_pid, wstatus, err = 0;
+ const int stack_size = 1024 * 1024;
+ struct iters_task_file *skel;
+ struct files_test_args args;
+ struct bpf_program *prog;
+ bool setup_end, test_end;
+ char *stack;
+
+ skel = iters_task_file__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "open_and_load"))
+ return;
+
+ if (!ASSERT_OK(skel->bss->err, "pre_test_err"))
+ goto cleanup_skel;
+
+ prog = bpf_object__find_program_by_name(skel->obj, "test_bpf_iter_task_file");
+ if (!ASSERT_OK_PTR(prog, "find_program_by_name"))
+ goto cleanup_skel;
+
+ prog_fd = bpf_program__fd(prog);
+ if (!ASSERT_GT(prog_fd, -1, "bpf_program__fd"))
+ goto cleanup_skel;
I don't think you need to check on this once we did iters_task_file__open_and_load
+
+ stack = (char *)malloc(stack_size);
+ if (!ASSERT_OK_PTR(stack, "clone_stack"))
+ goto cleanup_skel;
+
+ setup_end = false;
+ test_end = false;
+
+ args.setup_end = &setup_end;
+ args.test_end = &test_end;
+
+ /* Note that there is no CLONE_FILES */
+ child_pid = clone(task_file_test_process, stack + stack_size, CLONE_VM | SIGCHLD, &args);
+ if (!ASSERT_GT(child_pid, -1, "child_pid"))
+ goto cleanup_stack;
+
+ while (!setup_end)
+ ;
I thin kthe preferred way is to synchronize through pipe,
you can check prog_tests/uprobe_multi_test.c
Thanks for your reply.
Do we really need to use pipe? Currently this test is very simple.
In this test, all files opened by the test process will be closed first
so that there is an empty file description table, and then open the
test files.
This way the test process has only 3 newly opened files and the file
descriptors are always 0, 1, 2.
Although using pipe is feasible, this test will become more complicated
than it is now.
I see, I missed the close_range call.. anyway I'd still prefer pipe to busy waiting
perhaps you could use fentry probe triggered by the task_file_test_process
and do the fd/file iteration in there? that way there'be no need for the sync
jirka
Sorry for the delay, I have been a bit busy recently.
Thanks for letting me know, fentry is a good approach.
I used fentry in patch series v5.
