From: Sage Weil <sage@redhat.com>
Date: Mon, 19 Oct 2015 18:06:17 +0000 (-0400)
Subject: kv/LevelDBStore: make set() avoid bufferlist copy most of the time
X-Git-Tag: v10.0.1~116^2~16
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ca72d506cd73e5665a77e6113c83927f879d18ad;p=ceph.git

kv/LevelDBStore: make set() avoid bufferlist copy most of the time

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/kv/LevelDBStore.cc b/src/kv/LevelDBStore.cc
index 92c915810f68..a46558a5ca28 100644
--- a/src/kv/LevelDBStore.cc
+++ b/src/kv/LevelDBStore.cc
@@ -164,11 +164,19 @@ void LevelDBStore::LevelDBTransactionImpl::set(
   const bufferlist &to_set_bl)
 {
   string key = combine_strings(prefix, k);
-  //bufferlist::c_str() is non-constant, so we need to make a copy
-  bufferlist val = to_set_bl;
   bat.Delete(leveldb::Slice(key));
-  bat.Put(leveldb::Slice(key),
-	  leveldb::Slice(val.c_str(), val.length()));
+
+  // bufferlist::c_str() is non-constant, so we can't call c_str()
+  if (to_set_bl.is_contiguous() && to_set_bl.length() > 0) {
+    bat.Put(leveldb::Slice(key),
+	    leveldb::Slice(to_set_bl.buffers().front().c_str(),
+			   to_set_bl.length()));
+  } else {
+    // make a copy
+    bufferlist val = to_set_bl;
+    bat.Put(leveldb::Slice(key),
+	    leveldb::Slice(val.c_str(), val.length()));
+  }
 }
 
 void LevelDBStore::LevelDBTransactionImpl::rmkey(const string &prefix,