sampling: Recursively initialize watchdir

This is necessary to fix the per-cgroup benchmark

Author: tzussman

bench/bench_per_cgroup.py

@@ -208,6 +208,8 @@ def __init__(self, benchresults_cls=BenchResults, cli_args=None):
 
         # Only initialize cache_ext policies if not using default mode
         if not self.args.default:
+            # TODO: set the watch dirs more precisely to avoid needing recursive
+            # watch dir initialization.
             self.cache_ext_policy = CacheExtPolicy(
                 DEFAULT_CACHE_EXT_CGROUP, self.args.policy_loader, self.args.search_path
             )

policies/cache_ext_sampling.c

@@ -111,25 +111,28 @@ int main(int argc, char **argv)
 	}
 
 	// Initialize inode_watchlist map
-	ret = initialize_watch_dir_map(args.watch_dir,
-				       bpf_map__fd(skel->maps.inode_watchlist), false);
+	ret = initialize_watch_dir_map(
+	    args.watch_dir, bpf_map__fd(skel->maps.inode_watchlist), true);
+	if (ret) {
+		perror("Failed to initialize inode watchlist map");
+		goto cleanup;
+	}
 
-        // Attach cache_ext_ops to the specific cgroup
-        link =
-            bpf_map__attach_cache_ext_ops(skel->maps.sampling_ops, cgroup_fd);
-        if (link == NULL) {
+	// Attach cache_ext_ops to the specific cgroup
+	link = bpf_map__attach_cache_ext_ops(skel->maps.sampling_ops, cgroup_fd);
+	if (link == NULL) {
 		perror("Failed to attach BPF cache_ext_ops to cgroup");
-                goto cleanup;
-        }
+		goto cleanup;
+	}
 
-        // Attach probes
-        ret = cache_ext_sampling_bpf__attach(skel);
+	// Attach probes
+	ret = cache_ext_sampling_bpf__attach(skel);
 	if (ret) {
 		perror("Failed to attach BPF programs");
-                goto cleanup;
-        }
+		goto cleanup;
+	}
 
-        // Wait for keyboard input
+	// Wait for keyboard input
 	printf("Press any key to exit...\n");
 	getchar();