logd: report logging memory overhead

On 64 bit system, calculates to roughly 80 bytes of metadata and
list overhead for each entry.

In unit test example, we report 3388987 bytes of logging data and
overhead total, showmap reports 4652K of dirty data. We still want
to account for the remainder (fragmentation, other sources of
internal allocations etc).

Test: see values and check math
Bug: 31942525
Change-Id: I75f3162ce691faf1ae5a5dec18939fea535ede7e

1 files changed, 63 insertions, 38 deletions

diff --git a/logd/LogStatistics.cpp b/logd/LogStatistics.cpp
index c6ebd52dc..f69bc5046 100644
--- a/logd/LogStatistics.cpp
+++ b/logd/LogStatistics.cpp
@@ -21,6 +21,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <list>
+
 #include <log/logger.h>
 
 #include "LogStatistics.h"
@@ -467,55 +469,86 @@ std::string LogStatistics::format(uid_t uid, pid_t pid,
     short spaces = 1;
 
     log_id_for_each(id) {
-        if (!(logMask & (1 << id))) {
-            continue;
-        }
+        if (!(logMask & (1 << id))) continue;
         oldLength = output.length();
-        if (spaces < 0) {
-            spaces = 0;
-        }
+        if (spaces < 0) spaces = 0;
         output += android::base::StringPrintf("%*s%s", spaces, "",
                                               android_log_id_to_name(id));
         spaces += spaces_total + oldLength - output.length();
     }
+    if (spaces < 0) spaces = 0;
+    output += android::base::StringPrintf("%*sTotal", spaces, "");
 
-    spaces = 4;
-    output += "\nTotal";
+    static const char TotalStr[] = "\nTotal";
+    spaces = 10 - strlen(TotalStr);
+    output += TotalStr;
 
+    size_t totalSize = 0;
+    size_t totalEls = 0;
     log_id_for_each(id) {
-        if (!(logMask & (1 << id))) {
-            continue;
-        }
+        if (!(logMask & (1 << id))) continue;
         oldLength = output.length();
-        if (spaces < 0) {
-            spaces = 0;
-        }
-        output += android::base::StringPrintf("%*s%zu/%zu", spaces, "",
-                                              sizesTotal(id),
-                                              elementsTotal(id));
+        if (spaces < 0) spaces = 0;
+        size_t szs = sizesTotal(id);
+        totalSize += szs;
+        size_t els = elementsTotal(id);
+        totalEls += els;
+        output += android::base::StringPrintf("%*s%zu/%zu", spaces, "", szs, els);
         spaces += spaces_total + oldLength - output.length();
     }
+    if (spaces < 0) spaces = 0;
+    output += android::base::StringPrintf("%*s%zu/%zu", spaces, "", totalSize, totalEls);
 
-    spaces = 6;
-    output += "\nNow";
+    static const char NowStr[] = "\nNow";
+    spaces = 10 - strlen(NowStr);
+    output += NowStr;
 
+    totalSize = 0;
+    totalEls = 0;
     log_id_for_each(id) {
-        if (!(logMask & (1 << id))) {
-            continue;
+        if (!(logMask & (1 << id))) continue;
+
+        size_t els = elements(id);
+        if (els) {
+            oldLength = output.length();
+            if (spaces < 0) spaces = 0;
+            size_t szs = sizes(id);
+            totalSize += szs;
+            totalEls += els;
+            output += android::base::StringPrintf("%*s%zu/%zu", spaces, "", szs, els);
+            spaces -= output.length() - oldLength;
         }
+        spaces += spaces_total;
+    }
+    if (spaces < 0) spaces = 0;
+    output += android::base::StringPrintf("%*s%zu/%zu", spaces, "", totalSize, totalEls);
+
+    static const char OverheadStr[] = "\nOverhead";
+    spaces = 10 - strlen(OverheadStr);
+    output += OverheadStr;
+
+    totalSize = 0;
+    log_id_for_each(id) {
+        if (!(logMask & (1 << id))) continue;
 
         size_t els = elements(id);
         if (els) {
             oldLength = output.length();
-            if (spaces < 0) {
-                spaces = 0;
-            }
-            output += android::base::StringPrintf("%*s%zu/%zu", spaces, "",
-                                                  sizes(id), els);
+            if (spaces < 0) spaces = 0;
+            // estimate the std::list overhead.
+            static const size_t overhead =
+                ((sizeof(LogBufferElement) + sizeof(uint64_t) - 1) &
+                    -sizeof(uint64_t)) +
+                sizeof(std::list<LogBufferElement*>);
+            size_t szs = sizes(id) + els * overhead;
+            totalSize += szs;
+            output += android::base::StringPrintf("%*s%zu", spaces, "", szs);
             spaces -= output.length() - oldLength;
         }
         spaces += spaces_total;
     }
+    if (spaces < 0) spaces = 0;
+    output += android::base::StringPrintf("%*s%zu", spaces, "", totalSize);
 
     // Report on Chattiest
 
@@ -523,9 +556,7 @@ std::string LogStatistics::format(uid_t uid, pid_t pid,
 
     // Chattiest by application (UID)
     log_id_for_each(id) {
-        if (!(logMask & (1 << id))) {
-            continue;
-        }
+        if (!(logMask & (1 << id))) continue;
 
         name = (uid == AID_ROOT)
             ? "Chattiest UIDs in %s log buffer:"
@@ -539,27 +570,21 @@ std::string LogStatistics::format(uid_t uid, pid_t pid,
             : "Logging for this PID:";
         output += pidTable.format(*this, uid, pid, name);
         name = "Chattiest TIDs";
-        if (pid) {
-            name += android::base::StringPrintf(" for PID %d", pid);
-        }
+        if (pid) name += android::base::StringPrintf(" for PID %d", pid);
         name += ":";
         output += tidTable.format(*this, uid, pid, name);
     }
 
     if (enable && (logMask & (1 << LOG_ID_EVENTS))) {
         name = "Chattiest events log buffer TAGs";
-        if (pid) {
-            name += android::base::StringPrintf(" for PID %d", pid);
-        }
+        if (pid) name += android::base::StringPrintf(" for PID %d", pid);
         name += ":";
         output += tagTable.format(*this, uid, pid, name, LOG_ID_EVENTS);
     }
 
     if (enable && (logMask & (1 << LOG_ID_SECURITY))) {
         name = "Chattiest security log buffer TAGs";
-        if (pid) {
-            name += android::base::StringPrintf(" for PID %d", pid);
-        }
+        if (pid) name += android::base::StringPrintf(" for PID %d", pid);
         name += ":";
         output += securityTagTable.format(*this, uid, pid, name, LOG_ID_SECURITY);
     }