logcatd: fallocate and fadvise to logcat files

1. Pinning and fallocating blocks can avoid filesystem fragmentation.
2. Dropping caches can avoid memory pressure.
3. Use 2MB files

Bug: 136483670
Bug: 137180754
Change-Id: I0827bd903a677cbcbf3688983e847301cd541cdd
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
diff --git a/logcat/logcatd.rc b/logcat/logcatd.rc
index 26c9de3..e986184 100644
--- a/logcat/logcatd.rc
+++ b/logcat/logcatd.rc
@@ -52,7 +52,7 @@
     stop logcatd
 
 # logcatd service
-service logcatd /system/bin/logcatd -L -b ${logd.logpersistd.buffer:-all} -v threadtime -v usec -v printable -D -f /data/misc/logd/logcat -r ${logd.logpersistd.rotate_kbytes:-1024} -n ${logd.logpersistd.size:-256} --id=${ro.build.id}
+service logcatd /system/bin/logcatd -L -b ${logd.logpersistd.buffer:-all} -v threadtime -v usec -v printable -D -f /data/misc/logd/logcat -r ${logd.logpersistd.rotate_kbytes:-2048} -n ${logd.logpersistd.size:-256} --id=${ro.build.id}
     class late_start
     disabled
     # logd for write to /data/misc/logd, log group for read from log daemon