logd: disable worst uid prune for events buffer

There is some usage statistics that would be hurt by pruning by UID,
since _all_ usage statistics come from system_server. In other words
we expect it to be chatty. Until we formulate and evaluate a better
(eg: per-tag?) filtration mechanism, lets hold off pruning by UID.

Bug: 19608965
Change-Id: Iddd45a671e13bdcf3394c20919ad1f2e4ef36616

3 files changed, 6 insertions, 2 deletions

diff --git a/logd/LogBuffer.cpp b/logd/LogBuffer.cpp
index d8ffb02..260e237 100644
--- a/logd/LogBuffer.cpp
+++ b/logd/LogBuffer.cpp
@@ -279,7 +279,7 @@ void LogBuffer::prune(log_id_t id, unsigned long pruneRows, uid_t caller_uid) {
         size_t worst_sizes = 0;
         size_t second_worst_sizes = 0;
 
-        if ((id != LOG_ID_CRASH) && mPrune.worstUidEnabled()) {
+        if (worstUidEnabledForLogid(id) && mPrune.worstUidEnabled()) {
             std::unique_ptr<const UidEntry *[]> sorted = stats.sort(2, id);
 
             if (sorted.get()) {
diff --git a/logd/LogBufferElement.h b/logd/LogBufferElement.h
index cc18378..7b6456d 100644
--- a/logd/LogBufferElement.h
+++ b/logd/LogBufferElement.h
@@ -33,6 +33,10 @@ char *uidToName(uid_t uid);
 
 }
 
+static inline bool worstUidEnabledForLogid(log_id_t id) {
+    return (id != LOG_ID_CRASH) && (id != LOG_ID_EVENTS);
+}
+
 class LogBufferElement {
     const log_id_t mLogId;
     const uid_t mUid;
diff --git a/logd/LogStatistics.cpp b/logd/LogStatistics.cpp
index e0b8fd8..40fbfae 100644
--- a/logd/LogStatistics.cpp
+++ b/logd/LogStatistics.cpp
@@ -340,7 +340,7 @@ void LogStatistics::format(char **buf, uid_t uid, unsigned int logMask) {
                 android::String8 name("UID");
                 android::String8 size("Size");
                 android::String8 pruned("Pruned");
-                if (id == LOG_ID_CRASH) {
+                if (!worstUidEnabledForLogid(id)) {
                     pruned.setTo("");
                 }
                 format_line(output, name, size, pruned);