commit c3fc56c656c013864b2f418b30ad49b14007f412
author Mark Salyzyn <salyzyn@google.com> Wed Sep 16 15:34:00 2015 -0700
committer Mark Salyzyn <salyzyn@google.com> Wed Oct 07 16:24:57 2015 -0700
tree 45d6d63c3ccfde325ecd054e218ae2e7e1a1f4c5
parent 0d8e44a9d0bcd172751c8e2e31c7aee28609ebd2

logd: clearAll by UID speedup

- If doing a clear, skip accounting
- Ensure for busy checking, behind a region lock for instance, only
  break out if there was something to do. Basically move the filter
  actions first, and defer checking the region lock to the ends of
  the loops.

Bug: 23711431
Change-Id: Icc984f406880633516fb17dda84188a30d092e01

logd/LogBuffer.cpp

diff --git a/logd/LogBuffer.cpp b/logd/LogBuffer.cpp
index 35ee6f3..5cfc02f 100644
--- a/logd/LogBuffer.cpp
+++ b/logd/LogBuffer.cpp
@@ -377,6 +377,7 @@
 bool LogBuffer::prune(log_id_t id, unsigned long pruneRows, uid_t caller_uid) {
     LogTimeEntry *oldest = NULL;
     bool busy = false;
+    bool clearAll = pruneRows == ULONG_MAX;
 
     LogTimeEntry::lock();
 
@@ -394,29 +395,23 @@
     LogBufferElementCollection::iterator it;
 
     if (caller_uid != AID_ROOT) {
+        // Only here if clearAll condition (pruneRows == ULONG_MAX)
         for(it = mLogElements.begin(); it != mLogElements.end();) {
             LogBufferElement *e = *it;
 
+            if ((e->getLogId() != id) || (e->getUid() != caller_uid)) {
+                ++it;
+                continue;
+            }
+
             if (oldest && (oldest->mStart <= e->getSequence())) {
                 oldest->triggerSkip_Locked(id, pruneRows);
                 busy = true;
                 break;
             }
 
-            if (e->getLogId() != id) {
-                ++it;
-                continue;
-            }
-
-            if (e->getUid() == caller_uid) {
-                it = erase(it);
-                pruneRows--;
-                if (pruneRows == 0) {
-                    break;
-                }
-            } else {
-                ++it;
-            }
+            it = erase(it);
+            pruneRows--;
         }
         LogTimeEntry::unlock();
         return busy;
@@ -424,7 +419,7 @@
 
     // prune by worst offender by uid
     bool hasBlacklist = mPrune.naughty();
-    while (pruneRows > 0) {
+    while (!clearAll && (pruneRows > 0)) {
         // recalculate the worst offender on every batched pass
         uid_t worst = (uid_t) -1;
         size_t worst_sizes = 0;
@@ -589,7 +584,7 @@
     }
 
     bool whitelist = false;
-    bool hasWhitelist = mPrune.nice();
+    bool hasWhitelist = mPrune.nice() && !clearAll;
     it = mLogElements.begin();
     while((pruneRows > 0) && (it != mLogElements.end())) {
         LogBufferElement *e = *it;