Merge "lmkd: Maintain pid to taskname mapping to amend kill reports."

lmkd/lmkd.c

@@ -362,6 +362,9 @@ static uint32_t killcnt_total = 0;
 /* PAGE_SIZE / 1024 */
 static long page_k;
 
+static char* proc_get_name(int pid);
+static void poll_kernel();
+
 static bool parse_int64(const char* str, int64_t* ret) {
     char* endptr;
     long long val = strtoll(str, &endptr, 10);
@@ -634,6 +637,9 @@ static void cmd_procprio(LMKD_CTRL_PACKET packet) {
     }
 
     if (use_inkernel_interface) {
+#ifdef LMKD_LOG_STATS
+        stats_store_taskname(params.pid, proc_get_name(params.pid));
+#endif
         return;
     }
 
@@ -704,6 +710,16 @@ static void cmd_procremove(LMKD_CTRL_PACKET packet) {
     struct lmk_procremove params;
 
     if (use_inkernel_interface) {
+#ifdef LMKD_LOG_STATS
+        /* Perform an extra check before the pid is removed, after which it
+         * will be impossible for poll_kernel to get the taskname. poll_kernel()
+         * is potentially a long-running blocking function; however this method
+         * handles AMS requests but does not block AMS.*/
+        if (enable_stats_log) {
+            poll_kernel();
+        }
+        stats_remove_taskname(params.pid);
+#endif
         return;
     }
 
@@ -721,6 +737,9 @@ static void cmd_procpurge() {
     struct proc *next;
 
     if (use_inkernel_interface) {
+#ifdef LMKD_LOG_STATS
+        stats_purge_tasknames();
+#endif
         return;
     }
 
@@ -1925,7 +1944,6 @@ err_open_mpfd:
 
 #ifdef LMKD_LOG_STATS
 static int kernel_poll_fd = -1;
-
 static void poll_kernel() {
     if (kernel_poll_fd == -1) {
         // not waiting
@@ -1958,9 +1976,9 @@ static void poll_kernel() {
         /* only the death of the group leader process is logged */
         if (fields_read == 10 && group_leader_pid == pid) {
             int64_t process_start_time_ns = starttime * (NS_PER_SEC / sysconf(_SC_CLK_TCK));
-            stats_write_lmk_kill_occurred(log_ctx, LMK_KILL_OCCURRED, uid, taskname, oom_score_adj,
-                                          min_flt, maj_flt, rss_in_pages * PAGE_SIZE, 0, 0,
-                                          process_start_time_ns, min_score_adj);
+            stats_write_lmk_kill_occurred_pid(log_ctx, LMK_KILL_OCCURRED, uid, pid, oom_score_adj,
+                                              min_flt, maj_flt, rss_in_pages * PAGE_SIZE, 0, 0,
+                                              process_start_time_ns, min_score_adj);
         }
 
         free(taskname);

lmkd/statslog.c

@@ -18,8 +18,22 @@
 #include <errno.h>
 #include <log/log_id.h>
 #include <stats_event_list.h>
+#include <stdlib.h>
+#include <string.h>
 #include <time.h>
 
+#define LINE_MAX 128
+
+struct proc {
+    int pid;
+    char taskname[LINE_MAX];
+    struct proc* pidhash_next;
+};
+
+#define PIDHASH_SZ 1024
+static struct proc** pidhash = NULL;
+#define pid_hashfn(x) ((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))
+
 static int64_t getElapsedRealTimeNs() {
     struct timespec t;
     t.tv_sec = t.tv_nsec = 0;
@@ -57,6 +71,17 @@ stats_write_lmk_state_changed(android_log_context ctx, int32_t code, int32_t sta
     return write_to_logger(ctx, LOG_ID_STATS);
 }
 
+static struct proc* pid_lookup(int pid) {
+    struct proc* procp;
+
+    if (!pidhash) return NULL;
+
+    for (procp = pidhash[pid_hashfn(pid)]; procp && procp->pid != pid; procp = procp->pidhash_next)
+        ;
+
+    return procp;
+}
+
 /**
  * Logs the event when LMKD kills a process to reduce memory pressure.
  * Code: LMK_KILL_OCCURRED = 51
@@ -124,3 +149,74 @@ stats_write_lmk_kill_occurred(android_log_context ctx, int32_t code, int32_t uid
 
     return write_to_logger(ctx, LOG_ID_STATS);
 }
+
+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) {
+    struct proc* proc = pid_lookup(pid);
+    if (!proc) return -EINVAL;
+
+    return stats_write_lmk_kill_occurred(ctx, code, uid, proc->taskname, oom_score, pgfault,
+                                         pgmajfault, rss_in_bytes, cache_in_bytes, swap_in_bytes,
+                                         process_start_time_ns, min_oom_score);
+}
+
+static void proc_insert(struct proc* procp) {
+    if (!pidhash)
+        pidhash = calloc(PIDHASH_SZ, sizeof(struct proc));
+    int hval = pid_hashfn(procp->pid);
+    procp->pidhash_next = pidhash[hval];
+    pidhash[hval] = procp;
+}
+
+void stats_remove_taskname(int pid) {
+    if (!pidhash) return;
+
+    int hval = pid_hashfn(pid);
+    struct proc* procp;
+    struct proc* prevp;
+
+    for (procp = pidhash[hval], prevp = NULL; procp && procp->pid != pid;
+         procp = procp->pidhash_next)
+        prevp = procp;
+
+    if (!procp)
+        return;
+
+    if (!prevp)
+        pidhash[hval] = procp->pidhash_next;
+    else
+        prevp->pidhash_next = procp->pidhash_next;
+
+    free(procp);
+}
+
+void stats_store_taskname(int pid, const char* taskname) {
+    struct proc* procp = pid_lookup(pid);
+    if (procp != NULL && strcmp(procp->taskname, taskname) == 0)
+        return;
+    procp = malloc(sizeof(struct proc));
+    stats_remove_taskname(pid);
+    procp->pid = pid;
+    strncpy(procp->taskname, taskname, LINE_MAX - 1);
+    procp->taskname[LINE_MAX - 1] = '\0';
+    proc_insert(procp);
+}
+
+void stats_purge_tasknames() {
+    if (!pidhash) return;
+    struct proc* procp;
+    struct proc* next;
+    int i;
+    for (i = 0; i < PIDHASH_SZ; i++) {
+        procp = pidhash[i];
+        while (procp) {
+            next = procp->pidhash_next;
+            free(procp);
+            procp = next;
+        }
+    }
+    memset(pidhash, 0, PIDHASH_SZ * sizeof(struct proc));
+}

lmkd/statslog.h

@@ -80,6 +80,17 @@ struct memory_stat {
 int
 stats_write_lmk_state_changed(android_log_context ctx, 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);
+
 /**
  * Logs the event when LMKD kills a process to reduce memory pressure.
  * Code: LMK_KILL_OCCURRED = 51
@@ -91,6 +102,24 @@ stats_write_lmk_kill_occurred(android_log_context ctx, int32_t code, int32_t uid
                               int64_t swap_in_bytes, int64_t process_start_time_ns,
                               int32_t min_oom_score);
 
+/**
+ * Registers a process taskname by pid, while it is still alive.
+ */
+void
+stats_store_taskname(int pid, const char* taskname);
+
+/**
+ * Unregister all process tasknames.
+ */
+void
+stats_purge_tasknames();
+
+/**
+ * Unregister a process taskname, e.g. after it has been killed.
+ */
+void
+stats_remove_taskname(int pid);
+
 __END_DECLS
 
 #endif /* _STATSLOG_H_ */