commit 6510ff7a84f53d84b73a0c2aa0d26fe3e4b40a99
author Mark Salyzyn <salyzyn@google.com> Wed Sep 16 15:34:00 2015 -0700
committer Rom Lemarchand <romlem@google.com> Mon Nov 16 08:53:04 2015 -0800
tree 425772dee2b78c6f20a5f8350317e406388e183b
parent 99b31e9ddce04b61536cfb2429c8df377a7d9ead

logd: clearAll by UID speedup

(cherry pick from commit 2b25c66070f73413013caa48e1c171cb895869b5)

- 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 0dcc1c3..6c24b52 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;
@@ -592,7 +587,7 @@
     }
 
     bool whitelist = false;
-    bool hasWhitelist = mPrune.nice();
+    bool hasWhitelist = mPrune.nice() && !clearAll;
     it = mLogElements.begin();
     while((pruneRows > 0) && (it != mLogElements.end())) {
         LogBufferElement *e = *it;