From 5860e852f88e4eb859c5c6bf51b929cfdcfc9dd5 Mon Sep 17 00:00:00 2001
From: Suren Baghdasaryan <surenb@google.com>
Date: Fri, 19 May 2023 14:06:46 -0700
Subject: [PATCH] lmkd: remove unused LMK_STAT_STATE_CHANGED notification

The LmkStateChanged atom was historically used to mark lmk activity
and trigger additional stats polling. For more than a year this has
not been used at all (as statsd supported event-based triggering).
Remove unnecessary functionality.

Bug: 278174420
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I9f7f56711fabb751cf7a57ea7279759bcc4a3dff
---
 include/lmkd.h |  1 -
 lmkd.cpp       | 25 -------------------------
 statslog.cpp   | 12 ------------
 statslog.h     | 20 --------------------
 4 files changed, 58 deletions(-)

diff --git a/include/lmkd.h b/include/lmkd.h
index c814d17..d710d50 100644
--- a/include/lmkd.h
+++ b/include/lmkd.h
@@ -36,7 +36,6 @@ enum lmk_cmd {
     LMK_PROCKILL,           /* Unsolicited msg to subscribed clients on proc kills */
     LMK_UPDATE_PROPS,       /* Reinit properties */
     LMK_STAT_KILL_OCCURRED, /* Unsolicited msg to subscribed clients on proc kills for statsd log */
-    LMK_STAT_STATE_CHANGED, /* Unsolicited msg to subscribed clients on state changed */
 };
 
 /*
diff --git a/lmkd.cpp b/lmkd.cpp
index fcb06fe..02fb553 100644
--- a/lmkd.cpp
+++ b/lmkd.cpp
@@ -810,22 +810,6 @@ static void stats_write_lmk_kill_occurred_pid(int pid, struct kill_stat *kill_st
     }
 }
 
-/*
- * Write the state_changed over the data socket to be propagated via AMS to statsd
- */
-static void stats_write_lmk_state_changed(enum lmk_state state) {
-    LMKD_CTRL_PACKET packet_state_changed;
-    const size_t len = lmkd_pack_set_state_changed(packet_state_changed, state);
-    if (len == 0) {
-        return;
-    }
-    for (int i = 0; i < MAX_DATA_CONN; i++) {
-        if (data_sock[i].sock >= 0 && data_sock[i].async_event_mask & 1 << LMK_ASYNC_EVENT_STAT) {
-            ctrl_data_write(i, (char*)packet_state_changed, len);
-        }
-    }
-}
-
 static void poll_kernel(int poll_fd) {
     if (poll_fd == -1) {
         // not waiting
@@ -2423,7 +2407,6 @@ static int find_and_kill_process(int min_score_adj, struct kill_info *ki, union
                                  struct psi_data *pd) {
     int i;
     int killed_size = 0;
-    bool lmk_state_change_start = false;
     bool choose_heaviest_task = kill_heaviest_task;
 
     for (i = OOM_SCORE_ADJ_MAX; i >= min_score_adj; i--) {
@@ -2446,10 +2429,6 @@ static int find_and_kill_process(int min_score_adj, struct kill_info *ki, union
 
             killed_size = kill_one_process(procp, min_score_adj, ki, mi, wi, tm, pd);
             if (killed_size >= 0) {
-                if (!lmk_state_change_start) {
-                    lmk_state_change_start = true;
-                    stats_write_lmk_state_changed(STATE_START);
-                }
                 break;
             }
         }
@@ -2458,10 +2437,6 @@ static int find_and_kill_process(int min_score_adj, struct kill_info *ki, union
         }
     }
 
-    if (lmk_state_change_start) {
-        stats_write_lmk_state_changed(STATE_STOP);
-    }
-
     return killed_size;
 }
 
diff --git a/statslog.cpp b/statslog.cpp
index 26a6d86..6e6cb42 100644
--- a/statslog.cpp
+++ b/statslog.cpp
@@ -336,16 +336,4 @@ size_t lmkd_pack_set_kill_occurred(LMK_KILL_OCCURRED_PACKET packet,
     return index;
 }
 
-size_t lmkd_pack_set_state_changed(LMKD_CTRL_PACKET packet,
-                                   enum lmk_state state) {
-    if (!enable_stats_log) {
-        return 0;
-    }
-
-    packet[0] = htonl(LMK_STAT_STATE_CHANGED);
-    packet[1] = htonl(state);
-
-    return 2 * sizeof(int);
-}
-
 #endif /* LMKD_LOG_STATS */
diff --git a/statslog.h b/statslog.h
index e3f8b72..c61cf29 100644
--- a/statslog.h
+++ b/statslog.h
@@ -83,27 +83,12 @@ struct kill_stat {
 /* LMKD reply packet to hold data for the LmkKillOccurred statsd atom */
 typedef char LMK_KILL_OCCURRED_PACKET[LMKD_REPLY_MAX_SIZE];
 
-// If you update this, also update the corresponding stats enum mapping.
-enum lmk_state {
-    STATE_UNKNOWN = 0,
-    STATE_START,
-    STATE_STOP,
-};
-
 #ifdef LMKD_LOG_STATS
 
 #define PROC_STAT_FILE_PATH "/proc/%d/stat"
 #define PROC_STAT_BUFFER_SIZE 1024
 #define BYTES_IN_KILOBYTE 1024
 
-/**
- * Produces packet with the change in LMKD state which is used as start/stop boundaries for logging
- * LMK_KILL_OCCURRED event.
- * Code: LMK_STATE_CHANGED = 54
- */
-size_t lmkd_pack_set_state_changed(LMKD_CTRL_PACKET packet,
-                                   enum lmk_state state);
-
 /**
  * Produces packet with the event when LMKD kills a process to reduce memory pressure.
  * Code: LMK_KILL_OCCURRED = 51
@@ -137,11 +122,6 @@ const char* stats_get_task_name(int pid);
 
 #else /* LMKD_LOG_STATS */
 
-static inline size_t
-lmkd_pack_set_state_changed(LMKD_CTRL_PACKET packet __unused, enum lmk_state state __unused) {
-    return -EINVAL;
-}
-
 static inline size_t
 lmkd_pack_set_kill_occurred(LMK_KILL_OCCURRED_PACKET packet __unused,
                             struct kill_stat *kill_st __unused,