From: Kefu Chai <kchai@redhat.com>
Date: Wed, 30 Aug 2017 07:30:58 +0000 (+0800)
Subject: crush: get largest bucket id faster
X-Git-Tag: v13.0.1~1095^2~1
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=9ec4e216cbf4bf065bd1da77ec6fbc5c96760f2d;p=ceph-ci.git

crush: get largest bucket id faster

std::map<> is sorted, so we can always get the largest key by reading
it's last element.

Signed-off-by: Kefu Chai <kchai@redhat.com>
---

diff --git a/src/crush/CrushWrapper.cc b/src/crush/CrushWrapper.cc
index bf6f3cf5ab8..4a73b6feba2 100644
--- a/src/crush/CrushWrapper.cc
+++ b/src/crush/CrushWrapper.cc
@@ -765,10 +765,8 @@ map<int, string> CrushWrapper::get_parent_hierarchy(int id)
 
   // read the type map and get the name of the type with the largest ID
   int high_type = 0;
-  for (map<int, string>::iterator it = type_map.begin(); it != type_map.end(); ++it){
-    if ( (*it).first > high_type )
-      high_type = (*it).first;
-  }
+  if (!type_map.empty())
+    high_type = type_map.rbegin()->first;
 
   parent_id = get_item_id(parent_coord.second);