Fix the stats log in lmkd

1. let logs be written to statsd directly like all other stats logs.
   + stats log should not write to logd anymore(b/78239479)
2. fixed the log format
   + need to embed the elapsed real time in the log
3. fixed the log context reuse problem
   +reset the log context buffer and internal state before reuse

Bug: 78603347
Bug: 78239479

Test: tested with alloc_stress, and saw logs written to statsd

performance measurement (memory & cpu):
https://paste.googleplex.com/5508158646648832

Change-Id: I345f0eace8ba1687ff480fb88e9abba1d8533f76

lmkd/Android.bp

@@ -8,6 +8,7 @@ cc_binary {
     ],
     static_libs: [
         "libstatslogc",
+        "libstatssocket",
     ],
     local_include_dirs: ["include"],
     cflags: ["-Werror", "-DLMKD_TRACE_KILLS"],
@@ -31,6 +32,7 @@ cc_library_static {
     shared_libs: [
         "liblog",
     ],
+    static_libs: ["libstatssocket",],
 }
 
 cc_library_static {

lmkd/lmkd.c

@@ -37,7 +37,7 @@
 #include <log/log.h>
 
 #ifdef LMKD_LOG_STATS
-#include <statslog.h>
+#include "statslog.h"
 #endif
 
 /*

lmkd/statslog.c

@@ -16,8 +16,16 @@
 
 #include <assert.h>
 #include <errno.h>
-#include <log/log_event_list.h>
 #include <log/log_id.h>
+#include <stats_event_list.h>
+#include <time.h>
+
+static int64_t getElapsedRealTimeNs() {
+    struct timespec t;
+    t.tv_sec = t.tv_nsec = 0;
+    clock_gettime(CLOCK_BOOTTIME, &t);
+    return (int64_t)t.tv_sec * 1000000000LL + t.tv_nsec;
+}
 
 /**
  * Logs the change in LMKD state which is used as start/stop boundaries for logging
@@ -32,6 +40,12 @@ stats_write_lmk_state_changed(android_log_context ctx, int32_t code, int32_t sta
         return ret;
     }
 
+    reset_log_context(ctx);
+
+    if ((ret = android_log_write_int64(ctx, getElapsedRealTimeNs())) < 0) {
+        return ret;
+    }
+
     if ((ret = android_log_write_int32(ctx, code)) < 0) {
         return ret;
     }
@@ -39,7 +53,8 @@ stats_write_lmk_state_changed(android_log_context ctx, int32_t code, int32_t sta
     if ((ret = android_log_write_int32(ctx, state)) < 0) {
         return ret;
     }
-    return ret;
+
+    return write_to_logger(ctx, LOG_ID_STATS);
 }
 
 /**
@@ -56,6 +71,11 @@ stats_write_lmk_kill_occurred(android_log_context ctx, int32_t code, int32_t uid
     if (!ctx) {
         return ret;
     }
+    reset_log_context(ctx);
+
+    if ((ret = android_log_write_int64(ctx, getElapsedRealTimeNs())) < 0) {
+        return ret;
+    }
 
     if ((ret = android_log_write_int32(ctx, code)) < 0) {
         return ret;
@@ -93,8 +113,5 @@ stats_write_lmk_kill_occurred(android_log_context ctx, int32_t code, int32_t uid
         return ret;
     }
 
-    if ((ret = android_log_write_list(ctx, LOG_ID_STATS)) < 0) {
-        return ret;
-    }
-    return ret;
+    return write_to_logger(ctx, LOG_ID_STATS);
 }

lmkd/statslog.h

@@ -18,11 +18,11 @@
 #define _STATSLOG_H_
 
 #include <assert.h>
+#include <stats_event_list.h>
 #include <stdbool.h>
 #include <sys/cdefs.h>
 
 #include <cutils/properties.h>
-#include <log/log_event_list.h>
 
 __BEGIN_DECLS