common/Finisher: pass name as std::string_view to ctor

This eliminates a temporary `std::string`.

Additionally, convert the `tn` parameter to an rvalue reference and
move it to `thread_name`.

Signed-off-by: Max Kellermann <[email protected]>

Author: MaxKellermann

src/common/Finisher.cc

@@ -15,9 +15,9 @@ Finisher::Finisher(CephContext *cct_) :
   thread_name("fn_anonymous"),
   finisher_thread(this) {}
 
-Finisher::Finisher(CephContext *cct_, std::string name, std::string tn) :
+Finisher::Finisher(CephContext *cct_, std::string_view name, std::string &&tn) :
   cct(cct_), finisher_lock(ceph::make_mutex(fmt::format("Finisher::{}", name))),
-  thread_name(tn),
+  thread_name(std::move(tn)),
   finisher_thread(this) {
   PerfCountersBuilder b(cct, fmt::format("finisher-{}", name),
 			l_finisher_first, l_finisher_last);

src/common/Finisher.h

@@ -122,7 +122,7 @@ class Finisher {
   explicit Finisher(CephContext *cct_);
 
   /// Construct a named Finisher that logs its queue length.
-  Finisher(CephContext *cct_, std::string name, std::string tn);
+  Finisher(CephContext *cct_, std::string_view name, std::string &&tn);
   ~Finisher();
 };