lmkd: Isolate statslog related code from lmkd code

Move statsd related code out of lmkd.c to minimize ifdefs sprinkled around
the code and make it more maintainable.

Bug: 74119935
Test: lmkd_unit_test
Change-Id: Ib22f90fd380b9a31e09ab18ef16787bc07415ddf
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
diff --git a/lmkd/statslog.h b/lmkd/statslog.h
index 50d69f7..a09c7dd 100644
--- a/lmkd/statslog.h
+++ b/lmkd/statslog.h
@@ -18,6 +18,7 @@
 #define _STATSLOG_H_
 
 #include <assert.h>
+#include <inttypes.h>
 #include <stats_event_list.h>
 #include <stdbool.h>
 #include <sys/cdefs.h>
@@ -26,6 +27,20 @@
 
 __BEGIN_DECLS
 
+struct memory_stat {
+    int64_t pgfault;
+    int64_t pgmajfault;
+    int64_t rss_in_bytes;
+    int64_t cache_in_bytes;
+    int64_t swap_in_bytes;
+    int64_t process_start_time_ns;
+};
+
+struct kernel_poll_info {
+    int poll_fd;
+    void (*handler)(int poll_fd);
+};
+
 /*
  * These are defined in
  * http://cs/android/frameworks/base/cmds/statsd/src/atoms.proto
@@ -35,37 +50,17 @@
 #define LMK_STATE_CHANGE_START 1
 #define LMK_STATE_CHANGE_STOP 2
 
+#ifdef LMKD_LOG_STATS
+
 /*
  * The single event tag id for all stats logs.
  * Keep this in sync with system/core/logcat/event.logtags
  */
 const static int kStatsEventTag = 1937006964;
 
-static inline void statslog_init(android_log_context* log_ctx, bool* enable_stats_log) {
-    assert(log_ctx != NULL);
-    assert(enable_stats_log != NULL);
-    *enable_stats_log = property_get_bool("ro.lmk.log_stats", false);
+void statslog_init();
 
-    if (*enable_stats_log) {
-        *log_ctx = create_android_logger(kStatsEventTag);
-    }
-}
-
-static inline void statslog_destroy(android_log_context* log_ctx) {
-    assert(log_ctx != NULL);
-    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;
-    int64_t process_start_time_ns;
-};
+void statslog_destroy();
 
 #define MEMCG_PROCESS_MEMORY_STAT_PATH "/dev/memcg/apps/uid_%u/pid_%u/memory.stat"
 #define PROC_STAT_FILE_PATH "/proc/%d/stat"
@@ -78,47 +73,63 @@
  * Code: LMK_STATE_CHANGED = 54
  */
 int
-stats_write_lmk_state_changed(android_log_context ctx, int32_t code, int32_t state);
+stats_write_lmk_state_changed(int32_t code, int32_t state);
 
 /**
  * Logs the event when LMKD kills a process to reduce memory pressure.
  * Code: LMK_KILL_OCCURRED = 51
  */
 int
-stats_write_lmk_kill_occurred_pid(android_log_context ctx, int32_t code, int32_t uid, int pid,
-                                  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, int64_t process_start_time_ns,
-                                  int32_t min_oom_score);
+stats_write_lmk_kill_occurred(int32_t code, int32_t uid,
+                              char const* process_name, int32_t oom_score, int32_t min_oom_score,
+                              int tasksize, struct memory_stat *mem_st);
 
-/**
- * Logs the event when LMKD kills a process to reduce memory pressure.
- * Code: LMK_KILL_OCCURRED = 51
- */
-int
-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, int64_t process_start_time_ns,
-                              int32_t min_oom_score);
+struct memory_stat *stats_read_memory_stat(bool per_app_memcg, int pid, uid_t uid);
 
 /**
  * Registers a process taskname by pid, while it is still alive.
  */
-void
-stats_store_taskname(int pid, const char* taskname);
+void stats_store_taskname(int pid, const char* taskname, int poll_fd);
 
 /**
  * Unregister all process tasknames.
  */
-void
-stats_purge_tasknames();
+void stats_purge_tasknames();
 
 /**
  * Unregister a process taskname, e.g. after it has been killed.
  */
-void
-stats_remove_taskname(int pid);
+void stats_remove_taskname(int pid, int poll_fd);
+
+bool init_poll_kernel(struct kernel_poll_info *poll_info);
+
+#else /* LMKD_LOG_STATS */
+
+static inline void statslog_init() {}
+static inline void statslog_destroy() {}
+
+static inline int
+stats_write_lmk_state_changed(int32_t code __unused, int32_t state __unused) { return -EINVAL; }
+
+static inline int
+stats_write_lmk_kill_occurred(int32_t code __unused, int32_t uid __unused,
+                              char const* process_name __unused, int32_t oom_score __unused,
+                              int32_t min_oom_score __unused, int tasksize __unused,
+                              struct memory_stat *mem_st __unused) { return -EINVAL; }
+
+static inline struct memory_stat *stats_read_memory_stat(bool per_app_memcg __unused,
+                                    int pid __unused, uid_t uid __unused) { return NULL; }
+
+static inline void stats_store_taskname(int pid __unused, const char* taskname __unused,
+                                        int poll_fd __unused) {}
+
+static inline void stats_purge_tasknames() {}
+
+static inline void stats_remove_taskname(int pid __unused, int poll_fd __unused) {}
+
+static inline bool init_poll_kernel(struct kernel_poll_info *poll_info __unused) { return false; }
+
+#endif /* LMKD_LOG_STATS */
 
 __END_DECLS