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Message-ID: <ffcdb43a-8f7d-b16f-d59b-19293037af84@linux.intel.com>
Date: Wed, 13 May 2020 11:00:02 +0300
From: Alexey Budankov <alexey.budankov@...ux.intel.com>
To: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Andi Kleen <ak@...ux.intel.com>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH v3 2/9] perf evlist: implement control command handling
functions
Implement functions of initialization, finalization and processing
of control commands coming from control file descriptors.
Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
---
tools/perf/util/evlist.c | 128 +++++++++++++++++++++++++++++++++++++++
tools/perf/util/evlist.h | 17 ++++++
2 files changed, 145 insertions(+)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index aa61619fa304..ea14794e7389 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1707,3 +1707,131 @@ struct evsel *perf_evlist__reset_weak_group(struct evlist *evsel_list,
}
return leader;
}
+
+int evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack)
+{
+ if (ctl_fd == -1) {
+ pr_debug("Control descriptor is not initialized\n");
+ return 0;
+ }
+
+ evlist->ctl_fd_pos = perf_evlist__add_pollfd(&evlist->core, ctl_fd, NULL, POLLIN);
+ if (evlist->ctl_fd_pos < 0) {
+ evlist->ctl_fd_pos = -1;
+ pr_err("Failed to add ctl fd entry: %m\n");
+ return -1;
+ }
+
+ evlist->ctl_fd = ctl_fd;
+ evlist->ctl_fd_ack = ctl_fd_ack;
+
+ return 0;
+}
+
+int evlist__finalize_ctlfd(struct evlist *evlist)
+{
+ if (evlist->ctl_fd_pos == -1)
+ return 0;
+
+ evlist->core.pollfd.entries[evlist->ctl_fd_pos].fd = -1;
+ evlist->ctl_fd_pos = -1;
+ evlist->ctl_fd_ack = -1;
+ evlist->ctl_fd = -1;
+
+ return 0;
+}
+
+static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
+ char *cmd_data, size_t data_size)
+{
+ int err;
+ char c;
+ size_t bytes_read = 0;
+
+ memset(cmd_data, 0, data_size--);
+
+ do {
+ err = read(evlist->ctl_fd, &c, 1);
+ if (err > 0) {
+ if (c == '\n' || c == '\0')
+ break;
+ cmd_data[bytes_read++] = c;
+ if (bytes_read == data_size)
+ break;
+ } else {
+ if (err == -1)
+ pr_err("Failed to read from ctlfd %d: %m\n", evlist->ctl_fd);
+ break;
+ }
+ } while (1);
+
+ pr_debug("Message from ctl_fd: \"%s%s\"\n", cmd_data,
+ bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0");
+
+ if (err > 0) {
+ if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
+ strlen(EVLIST_CTL_CMD_ENABLE_TAG))) {
+ *cmd = EVLIST_CTL_CMD_ENABLE;
+ } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG,
+ strlen(EVLIST_CTL_CMD_DISABLE_TAG))) {
+ *cmd = EVLIST_CTL_CMD_DISABLE;
+ }
+ }
+
+ return err;
+}
+
+static int evlist__ctlfd_ack(struct evlist *evlist)
+{
+ int err;
+
+ if (evlist->ctl_fd_ack == -1)
+ return 0;
+
+ err = write(evlist->ctl_fd_ack, EVLIST_CTL_CMD_ACK_TAG,
+ sizeof(EVLIST_CTL_CMD_ACK_TAG));
+ if (err == -1)
+ pr_err("failed to write to ctl_ack_fd %d: %m\n", evlist->ctl_fd_ack);
+
+ return err;
+}
+
+int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
+{
+ int err = 0;
+ char cmd_data[EVLIST_CTL_CMD_MAX_LEN];
+ int ctlfd_pos = evlist->ctl_fd_pos;
+ struct pollfd *entries = evlist->core.pollfd.entries;
+
+ if (!entries[ctlfd_pos].revents)
+ return 0;
+
+ if (entries[ctlfd_pos].revents & POLLIN) {
+ err = evlist__ctlfd_recv(evlist, cmd, cmd_data,
+ EVLIST_CTL_CMD_MAX_LEN);
+ if (err > 0) {
+ switch (*cmd) {
+ case EVLIST_CTL_CMD_ENABLE:
+ evlist__enable(evlist);
+ break;
+ case EVLIST_CTL_CMD_DISABLE:
+ evlist__disable(evlist);
+ break;
+ case EVLIST_CTL_CMD_ACK:
+ case EVLIST_CTL_CMD_UNSUPPORTED:
+ default:
+ pr_debug("ctlfd: unsupported %d\n", *cmd);
+ break;
+ }
+ if (!(*cmd == EVLIST_CTL_CMD_ACK || *cmd == EVLIST_CTL_CMD_UNSUPPORTED))
+ evlist__ctlfd_ack(evlist);
+ }
+ }
+
+ if (entries[ctlfd_pos].revents & (POLLHUP | POLLERR))
+ evlist__finalize_ctlfd(evlist);
+ else
+ entries[ctlfd_pos].revents = 0;
+
+ return err;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 62f259d89b41..0554f8d2a65b 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -358,4 +358,21 @@ void perf_evlist__force_leader(struct evlist *evlist);
struct evsel *perf_evlist__reset_weak_group(struct evlist *evlist,
struct evsel *evsel,
bool close);
+#define EVLIST_CTL_CMD_ENABLE_TAG "enable"
+#define EVLIST_CTL_CMD_DISABLE_TAG "disable"
+#define EVLIST_CTL_CMD_ACK_TAG "ack\n"
+
+#define EVLIST_CTL_CMD_MAX_LEN 64
+
+enum evlist_ctl_cmd {
+ EVLIST_CTL_CMD_UNSUPPORTED = 0,
+ EVLIST_CTL_CMD_ENABLE,
+ EVLIST_CTL_CMD_DISABLE,
+ EVLIST_CTL_CMD_ACK
+};
+
+int evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
+int evlist__finalize_ctlfd(struct evlist *evlist);
+int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
+
#endif /* __PERF_EVLIST_H */
--
2.24.1
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