lmkd: move sundry pieces to statslog.h

Pragma once is not part of the standard, and is actually a gnu
C++ addition. Android coding standard requires the #ifndef header
wrappers. Moved things that belong in statslog.h from the lmkd files.

SideEffects: None
Test: lmkd_unit_tests
Bug: 33808187
Bug: 72838192
Change-Id: I9686b1a0791ee2b723d05b91905eda0bb64a1156

lmkd.c

@@ -37,7 +37,6 @@
 #include <log/log.h>
 
 #ifdef LMKD_LOG_STATS
-#include <log/log_event_list.h>
 #include <statslog.h>
 #endif
 
@@ -76,18 +75,6 @@
 #define ARRAY_SIZE(x)   (sizeof(x) / sizeof(*(x)))
 #define EIGHT_MEGA (1 << 23)
 
-#ifdef LMKD_LOG_STATS
-#define MEMCG_PROCESS_MEMORY_STAT_PATH "/dev/memcg/apps/uid_%d/pid_%d/memory.stat"
-/*
- * These are defined in
- * http://cs/android/frameworks/base/cmds/statsd/src/atoms.proto
- */
-#define LMK_KILL_OCCURRED 51
-#define LMK_STATE_CHANGED 54
-#define LMK_STATE_CHANGE_START 1
-#define LMK_STATE_CHANGE_STOP 2
-#endif
-
 /* default to old in-kernel interface if no memory pressure events */
 static int use_inkernel_interface = 1;
 static bool has_inkernel_module;
@@ -182,13 +169,6 @@ struct proc {
 };
 
 #ifdef LMKD_LOG_STATS
-struct memory_stat {
-   int64_t pgfault;
-   int64_t pgmajfault;
-   int64_t rss_in_bytes;
-   int64_t cache_in_bytes;
-   int64_t swap_in_bytes;
-};
 static bool enable_stats_log;
 static android_log_context log_ctx;
 #endif
@@ -1221,11 +1201,7 @@ int main(int argc __unused, char **argv __unused) {
         (unsigned long)property_get_int32("ro.lmk.kill_timeout_ms", 0);
 
 #ifdef LMKD_LOG_STATS
-    enable_stats_log = property_get_bool("ro.lmk.log_stats", false);
+    statlog_init();
-
-    if (enable_stats_log) {
-        log_ctx = create_android_logger(kStatsEventTag);
-    }
 #endif
 
     // MCL_ONFAULT pins pages as they fault instead of loading
@@ -1245,9 +1221,7 @@ int main(int argc __unused, char **argv __unused) {
         mainloop();
 
 #ifdef LMKD_LOG_STATS
-    if (log_ctx) {
+    statslog_destroy();
-        android_log_destroy(&log_ctx);
-    }
 #endif
 
     ALOGI("exiting");

statslog.h

@@ -14,11 +14,50 @@
  *  limitations under the License.
  */
 
-#pragma once
+#ifndef _STATSLOG_H_
+#define _STATSLOG_H_
 
+#include <stdbool.h>
 #include <sys/cdefs.h>
+
+#include <cutils/properties.h>
+#include <log/log_event_list.h>
+
 __BEGIN_DECLS
 
+/*
+ * These are defined in
+ * http://cs/android/frameworks/base/cmds/statsd/src/atoms.proto
+ */
+#define LMK_KILL_OCCURRED 51
+#define LMK_STATE_CHANGED 54
+#define LMK_STATE_CHANGE_START 1
+#define LMK_STATE_CHANGE_STOP 2
+
+static inline void statslog_init() {
+    enable_stats_log = property_get_bool("ro.lmk.log_stats", false);
+
+    if (enable_stats_log) {
+        log_ctx = create_android_logger(kStatsEventTag);
+    }
+}
+
+static inline void statslog_destroy() {
+    if (log_ctx) {
+        android_log_destroy(&log_ctx);
+    }
+}
+
+struct memory_stat {
+    int64_t pgfault;
+    int64_t pgmajfault;
+    int64_t rss_in_bytes;
+    int64_t cache_in_bytes;
+    int64_t swap_in_bytes;
+};
+
+#define MEMCG_PROCESS_MEMORY_STAT_PATH "/dev/memcg/apps/uid_%u/pid_%u/memory.stat"
+
 /*
  * The single event tag id for all stats logs.
  * Keep this in sync with system/core/logcat/event.logtags
@@ -42,4 +81,7 @@ stats_write_lmk_kill_occurred(android_log_context ctx, int32_t code, int32_t uid
                               char const* process_name, int32_t oom_score, int64_t pgfault,
                               int64_t pgmajfault, int64_t rss_in_bytes, int64_t cache_in_bytes,
                               int64_t swap_in_bytes);
+
 __END_DECLS
+
+#endif /* _STATSLOG_H_ */