osdc: Use boost::container::small_vector for ops vector

This way making an ObjectOperation won't require allocations just
for a few ops.

Signed-off-by: Adam C. Emerson <aemerson@redhat.com>

diff --git a/src/crimson/osd/osd.h b/src/crimson/osd/osd.h
index d0f7c2230bd3a9941233045b912b7c31ac200098..47e8280368afb9ce8d08291c21f3454634247f15 100644 (file)
--- a/src/crimson/osd/osd.h
+++ b/src/crimson/osd/osd.h
@@ -26,6 +26,7 @@
 #include "crimson/osd/pg_map.h"
 #include "crimson/osd/osd_operations/peering_event.h"
 
+#include "messages/MOSDOp.h"
 #include "osd/PeeringState.h"
 #include "osd/osd_types.h"
 #include "osd/osd_perf_counters.h"
@@ -33,7 +34,6 @@
 
 class MCommand;
 class MOSDMap;
-class MOSDOp;
 class MOSDRepOpReply;
 class MOSDRepOp;
 class OSDMap;

diff --git a/src/crimson/osd/osd_operations/background_recovery.h b/src/crimson/osd/osd_operations/background_recovery.h
index 73f336fc366ca2e3b01c03853bf8f6a45969c7e1..65ea5220c9ba2cfc314a0478962e20ed99353ac9 100644 (file)
--- a/src/crimson/osd/osd_operations/background_recovery.h
+++ b/src/crimson/osd/osd_operations/background_recovery.h
@@ -7,7 +7,7 @@
 #include "crimson/osd/osd_operation.h"
 #include "crimson/common/type_helpers.h"
 
-class MOSDOp;
+#include "messages/MOSDOp.h"
 
 namespace crimson::osd {
 class PG;

diff --git a/src/crimson/osd/osd_operations/client_request.h b/src/crimson/osd/osd_operations/client_request.h
index eb81e0c3b949c8057170ff648bdd6b12976fdd90..de0e914d8e6fa8efc8574c1bf6913c52ab14d6b9 100644 (file)
--- a/src/crimson/osd/osd_operations/client_request.h
+++ b/src/crimson/osd/osd_operations/client_request.h
@@ -7,8 +7,7 @@
 #include "crimson/net/Connection.h"
 #include "crimson/osd/osd_operation.h"
 #include "crimson/common/type_helpers.h"
-
-class MOSDOp;
+#include "messages/MOSDOp.h"
 
 namespace crimson::osd {
 class PG;

diff --git a/src/crimson/osd/pg.h b/src/crimson/osd/pg.h
index c10139bff762d291509a330257d9222312985edd..50905169e24f1cd0466ca925bae69fd7fd4d0948 100644 (file)
--- a/src/crimson/osd/pg.h
+++ b/src/crimson/osd/pg.h
@@ -14,6 +14,8 @@
 
 #include "common/dout.h"
 #include "crimson/net/Fwd.h"
+#include "messages/MOSDRepOpReply.h"
+#include "messages/MOSDOpReply.h"
 #include "os/Transaction.h"
 #include "osd/osd_types.h"
 #include "crimson/osd/object_context.h"

diff --git a/src/crimson/osd/pg_backend.h b/src/crimson/osd/pg_backend.h
index 89ca0905869dde94a8e1b8656154c2bfebb1648c..001e98eb26826ee3421225d8eb9fbcca9f7acacd 100644 (file)
--- a/src/crimson/osd/pg_backend.h
+++ b/src/crimson/osd/pg_backend.h
@@ -14,13 +14,15 @@
 #include "crimson/osd/acked_peers.h"
 #include "crimson/osd/pg.h"
 #include "crimson/common/shared_lru.h"
+#include "messages/MOSDOp.h"
+#include "messages/MOSDOpReply.h"
+#include "os/Transaction.h"
 #include "osd/osd_types.h"
 #include "crimson/osd/object_context.h"
 #include "crimson/osd/osd_operation.h"
 #include "crimson/osd/osd_operations/osdop_params.h"
 
 struct hobject_t;
-class MOSDRepOpReply;
 
 namespace ceph::os {
   class Transaction;

diff --git a/src/messages/MOSDOp.h b/src/messages/MOSDOp.h
index 43bd400546982a7e3b8d0317f5f0783113adbcfa..5301f0a43b255703910ab7743cee16629891011c 100644 (file)
--- a/src/messages/MOSDOp.h
+++ b/src/messages/MOSDOp.h
@@ -30,8 +30,10 @@
  *
  */
 
-class OSD;
+class MOSDOpReply;
 
+namespace _mosdop {
+template<typename V>
 class MOSDOp : public MOSDFastDispatchOp {
 private:
   static constexpr int HEAD_VERSION = 8;
@@ -54,7 +56,7 @@ private:
   std::atomic<bool> final_decode_needed;
   //
 public:
-  std::vector<OSDOp> ops;
+  V ops;
 private:
   snapid_t snap_seq;
   std::vector<snapid_t> snaps;
@@ -64,7 +66,7 @@ private:
   osd_reqid_t reqid; // reqid explicitly set by sender
 
 public:
-  friend class MOSDOpReply;
+  friend MOSDOpReply;
 
   ceph_tid_t get_client_tid() { return header.tid; }
   void set_snapid(const snapid_t& s) {
@@ -598,6 +600,9 @@ private:
   template<class T, typename... Args>
   friend boost::intrusive_ptr<T> ceph::make_message(Args&&... args);
 };
+}
+
+using MOSDOp = _mosdop::MOSDOp<std::vector<OSDOp>>;
 
 
 #endif

diff --git a/src/msg/MessageRef.h b/src/msg/MessageRef.h
index 5eb3655cb848e1378373f6f5d8f52a2371eb6c4c..4f30f0b352a91f769e514fad8ea9ba0a4c4882b5 100644 (file)
--- a/src/msg/MessageRef.h
+++ b/src/msg/MessageRef.h
@@ -133,8 +133,6 @@ class MOSDForceRecovery;
 class MOSDFull;
 class MOSDMap;
 class MOSDMarkMeDown;
-class MOSDOp;
-class MOSDOpReply;
 class MOSDPeeringOp;
 class MOSDPGBackfill;
 class MOSDPGBackfillRemove;

diff --git a/src/osd/OSD.h b/src/osd/OSD.h
index 522de0cc846d0a2cd180a427e385383579b18a9d..0aca510e0844f1820639bc25d9cc73a830cda1ee 100644 (file)
--- a/src/osd/OSD.h
+++ b/src/osd/OSD.h
@@ -91,7 +91,6 @@ class TestOpsSocketHook;
 struct C_FinishSplits;
 struct C_OpenPGs;
 class LogChannel;
-class MOSDOp;
 
 class MOSDPGCreate2;
 class MOSDPGQuery;

diff --git a/src/osd/PG.h b/src/osd/PG.h
index cb647574dc4623add79cadbefebb734592f3ae35..50a968de78cf2924e11d8da264a8e0d46a7b9a09 100644 (file)
--- a/src/osd/PG.h
+++ b/src/osd/PG.h
@@ -55,7 +55,6 @@ class OSD;
 class OSDService;
 class OSDShard;
 class OSDShardPGSlot;
-class MOSDOp;
 class MOSDPGScan;
 class MOSDPGBackfill;
 class MOSDPGInfo;

diff --git a/src/osd/PrimaryLogPG.h b/src/osd/PrimaryLogPG.h
index 57d153727a365b329b332a40aa606fd3ffb638c9..ebc36e8117091d7ff1265c34e1e9f4743aeb032c 100644 (file)
--- a/src/osd/PrimaryLogPG.h
+++ b/src/osd/PrimaryLogPG.h
@@ -40,8 +40,6 @@ class PrimaryLogPG;
 class PGLSFilter;
 class HitSet;
 struct TierAgentState;
-class MOSDOp;
-class MOSDOpReply;
 class OSDService;
 
 void intrusive_ptr_add_ref(PrimaryLogPG *pg);

diff --git a/src/osd/osd_op_util.h b/src/osd/osd_op_util.h
index 92dac0f5cd322eb7ca560fff4b365166677dcd1f..872dd502c18e2d910b07068075adbb32b42f9d26 100644 (file)
--- a/src/osd/osd_op_util.h
+++ b/src/osd/osd_op_util.h
@@ -8,7 +8,8 @@
 
 #include "osd/OSDMap.h"
 
-class MOSDOp;
+#include "messages/MOSDOp.h"
+
 class OpInfo {
 public:
   struct ClassInfo {

diff --git a/src/osd/osd_types.cc b/src/osd/osd_types.cc
index 3c235ecc682dc03026523b4e48688ef6bfaf58d9..557a6b1a06c7e690bc27f010c18d900dc2a1e6b0 100644 (file)
--- a/src/osd/osd_types.cc
+++ b/src/osd/osd_types.cc
@@ -6776,26 +6776,6 @@ ostream& operator<<(ostream& out, const OSDOp& op)
 }
 
 
-void OSDOp::split_osd_op_vector_in_data(vector<OSDOp>& ops, ceph::buffer::list& in)
-{
-  ceph::buffer::list::iterator datap = in.begin();
-  for (unsigned i = 0; i < ops.size(); i++) {
-    if (ops[i].op.payload_len) {
-      datap.copy(ops[i].op.payload_len, ops[i].indata);
-    }
-  }
-}
-
-void OSDOp::merge_osd_op_vector_in_data(vector<OSDOp>& ops, ceph::buffer::list& out)
-{
-  for (unsigned i = 0; i < ops.size(); i++) {
-    if (ops[i].indata.length()) {
-      ops[i].op.payload_len = ops[i].indata.length();
-      out.append(ops[i].indata);
-    }
-  }
-}
-
 void OSDOp::split_osd_op_vector_out_data(vector<OSDOp>& ops, ceph::buffer::list& in)
 {
   auto datap = in.begin();
@@ -6816,33 +6796,6 @@ void OSDOp::merge_osd_op_vector_out_data(vector<OSDOp>& ops, ceph::buffer::list&
   }
 }
 
-void OSDOp::clear_data(vector<OSDOp>& ops)
-{
-  for (unsigned i = 0; i < ops.size(); i++) {
-    OSDOp& op = ops[i];
-    op.outdata.clear();
-    if (ceph_osd_op_type_attr(op.op.op) &&
-        op.op.xattr.name_len &&
-       op.indata.length() >= op.op.xattr.name_len) {
-      ceph::buffer::list bl;
-      bl.push_back(ceph::buffer::ptr_node::create(op.op.xattr.name_len));
-      bl.begin().copy_in(op.op.xattr.name_len, op.indata);
-      op.indata.claim(bl);
-    } else if (ceph_osd_op_type_exec(op.op.op) &&
-               op.op.cls.class_len &&
-              op.indata.length() >
-                (op.op.cls.class_len + op.op.cls.method_len)) {
-      __u8 len = op.op.cls.class_len + op.op.cls.method_len;
-      ceph::buffer::list bl;
-      bl.push_back(ceph::buffer::ptr_node::create(len));
-      bl.begin().copy_in(len, op.indata);
-      op.indata.claim(bl);
-    } else {
-      op.indata.clear();
-    }
-  }
-}
-
 int prepare_info_keymap(
   CephContext* cct,
   map<string,bufferlist> *km,

diff --git a/src/osd/osd_types.h b/src/osd/osd_types.h
index 3169e63c369eefd204a1a9828dbc93236feba96d..630ff3d07aa0e5c21125dad22339a3c40f891104 100644 (file)
--- a/src/osd/osd_types.h
+++ b/src/osd/osd_types.h
@@ -3960,7 +3960,16 @@ struct OSDOp {
    * @param ops [out] vector of OSDOps
    * @param in  [in] combined data buffer
    */
-  static void split_osd_op_vector_in_data(std::vector<OSDOp>& ops, ceph::buffer::list& in);
+  template<typename V>
+  static void split_osd_op_vector_in_data(V& ops,
+                                         ceph::buffer::list& in) {
+    ceph::buffer::list::iterator datap = in.begin();
+    for (unsigned i = 0; i < ops.size(); i++) {
+      if (ops[i].op.payload_len) {
+       datap.copy(ops[i].op.payload_len, ops[i].indata);
+      }
+    }
+  }
 
   /**
    * merge indata members of a vector of OSDOp into a single ceph::buffer::list
@@ -3971,7 +3980,15 @@ struct OSDOp {
    * @param ops [in] vector of OSDOps
    * @param out [out] combined data buffer
    */
-  static void merge_osd_op_vector_in_data(std::vector<OSDOp>& ops, ceph::buffer::list& out);
+  template<typename V>
+  static void merge_osd_op_vector_in_data(V& ops, ceph::buffer::list& out) {
+    for (unsigned i = 0; i < ops.size(); i++) {
+      if (ops[i].indata.length()) {
+       ops[i].op.payload_len = ops[i].indata.length();
+       out.append(ops[i].indata);
+      }
+    }
+  }
 
   /**
    * split a ceph::buffer::list into constituent outdata members of a vector of OSDOps
@@ -3994,11 +4011,35 @@ struct OSDOp {
    *
    * @param ops [in] vector of OSDOps
    */
-  static void clear_data(std::vector<OSDOp>& ops);
+  template<typename V>
+  static void clear_data(V& ops) {
+    for (unsigned i = 0; i < ops.size(); i++) {
+      OSDOp& op = ops[i];
+      op.outdata.clear();
+      if (ceph_osd_op_type_attr(op.op.op) &&
+         op.op.xattr.name_len &&
+         op.indata.length() >= op.op.xattr.name_len) {
+       ceph::buffer::list bl;
+       bl.push_back(ceph::buffer::ptr_node::create(op.op.xattr.name_len));
+       bl.begin().copy_in(op.op.xattr.name_len, op.indata);
+       op.indata.claim(bl);
+      } else if (ceph_osd_op_type_exec(op.op.op) &&
+                op.op.cls.class_len &&
+                op.indata.length() >
+                (op.op.cls.class_len + op.op.cls.method_len)) {
+       __u8 len = op.op.cls.class_len + op.op.cls.method_len;
+       ceph::buffer::list bl;
+       bl.push_back(ceph::buffer::ptr_node::create(len));
+       bl.begin().copy_in(len, op.indata);
+       op.indata.claim(bl);
+      } else {
+       op.indata.clear();
+      }
+    }
+  }
 };
 std::ostream& operator<<(std::ostream& out, const OSDOp& op);
 
-
 struct pg_log_op_return_item_t {
   int32_t rval;
   ceph::buffer::list bl;

diff --git a/src/osdc/Filer.cc b/src/osdc/Filer.cc
index d97e5de0a61aa4e12840e1f05c7a6187fe548043..7a64e38ccdbb899af04f7a6351efe58c14463382 100644 (file)
--- a/src/osdc/Filer.cc
+++ b/src/osdc/Filer.cc
@@ -415,7 +415,7 @@ void Filer::truncate(inodeno_t ino,
   if (num_objs == 1) {
     vector<ObjectExtent> extents;
     Striper::file_to_extents(cct, ino, layout, offset, len, 0, extents);
-    vector<OSDOp> ops(1);
+    osdc_opvec ops(1);
     ops[0].op.op = CEPH_OSD_OP_TRIMTRUNC;
     ops[0].op.extent.truncate_seq = truncate_seq;
     ops[0].op.extent.truncate_size = extents[0].offset;
@@ -474,7 +474,7 @@ void Filer::_do_truncate_range(TruncRange *tr, int fin)
 
   // Issue objecter ops outside tr->lock to avoid lock dependency loop
   for (const auto& p : extents) {
-    vector<OSDOp> ops(1);
+    osdc_opvec ops(1);
     ops[0].op.op = CEPH_OSD_OP_TRIMTRUNC;
     ops[0].op.extent.truncate_size = p.offset;
     ops[0].op.extent.truncate_seq = tr->truncate_seq;

diff --git a/src/osdc/Objecter.cc b/src/osdc/Objecter.cc
index dc0a6ef09c727da8c0f1c806064580435019afa1..516fe63afd1c2bf8d993407003967f0dfc8284d8 100644 (file)
--- a/src/osdc/Objecter.cc
+++ b/src/osdc/Objecter.cc
@@ -523,8 +523,8 @@ void Objecter::_send_linger(LingerOp *info,
 {
   ceph_assert(sul.owns_lock() && sul.mutex() == &rwlock);
 
-  vector<OSDOp> opv;
   fu2::unique_function<Op::OpSig> oncommit;
+  osdc_opvec opv;
   std::shared_lock watchl(info->watch_lock);
   cb::list *poutbl = nullptr;
   if (info->registered && info->is_watch) {
@@ -685,7 +685,7 @@ void Objecter::_send_linger_ping(LingerOp *info)
   ldout(cct, 10) << __func__ << " " << info->linger_id << " now " << now
                 << dendl;
 
-  vector<OSDOp> opv(1);
+  osdc_opvec opv(1);
   opv[0].op.op = CEPH_OSD_OP_WATCH;
   opv[0].op.watch.cookie = info->get_cookie();
   opv[0].op.watch.op = CEPH_OSD_WATCH_OP_PING;
@@ -3085,7 +3085,7 @@ void Objecter::_finish_op(Op *op, int r)
   op->put();
 }
 
-MOSDOp *Objecter::_prepare_osd_op(Op *op)
+Objecter::MOSDOp *Objecter::_prepare_osd_op(Op *op)
 {
   // rwlock is locked
 
@@ -3212,12 +3212,10 @@ void Objecter::_send_op(Op *op)
   op->session->con->send_message(m);
 }
 
-int Objecter::calc_op_budget(const vector<OSDOp>& ops)
+int Objecter::calc_op_budget(const bc::small_vector_base<OSDOp>& ops)
 {
   int op_budget = 0;
-  for (vector<OSDOp>::const_iterator i = ops.begin();
-       i != ops.end();
-       ++i) {
+  for (auto i = ops.begin(); i != ops.end(); ++i) {
     if (i->op.op & CEPH_OSD_OP_MODE_WR) {
       op_budget += i->indata.length();
     } else if (ceph_osd_op_mode_read(i->op.op)) {

diff --git a/src/osdc/Objecter.h b/src/osdc/Objecter.h
index c7d132a50879ac4faea15a7afae1ed413b0da6dc..a34e02fe018ad2fee13ad2f4bcc6b2a00c9adf00 100644 (file)
--- a/src/osdc/Objecter.h
+++ b/src/osdc/Objecter.h
@@ -26,6 +26,7 @@
 #include <type_traits>
 #include <variant>
 
+#include <boost/container/small_vector.hpp>
 #include <boost/asio.hpp>
 
 #include <fmt/format.h>
@@ -73,18 +74,24 @@ struct EnumerationContext;
 template<typename t>
 struct CB_EnumerateReply;
 
+inline constexpr std::size_t osdc_opvec_len = 2;
+using osdc_opvec = boost::container::small_vector<OSDOp, osdc_opvec_len>;
+
 // -----------------------------------------
 
 struct ObjectOperation {
-  std::vector<OSDOp> ops;
+  osdc_opvec ops;
   int flags = 0;
   int priority = 0;
 
-  std::vector<ceph::buffer::list*> out_bl;
-  std::vector<fu2::unique_function<void(boost::system::error_code, int,
-                                       const ceph::buffer::list& bl) &&>> out_handler;
-  std::vector<int*> out_rval;
-  std::vector<boost::system::error_code*> out_ec;
+  boost::container::small_vector<ceph::buffer::list*, osdc_opvec_len> out_bl;
+  boost::container::small_vector<
+    fu2::unique_function<void(boost::system::error_code, int,
+                             const ceph::buffer::list& bl) &&>,
+    osdc_opvec_len> out_handler;
+  boost::container::small_vector<int*, osdc_opvec_len> out_rval;
+  boost::container::small_vector<boost::system::error_code*,
+                                osdc_opvec_len> out_ec;
 
   ObjectOperation() = default;
   ObjectOperation(const ObjectOperation&) = delete;
@@ -1562,8 +1569,11 @@ struct ObjectOperation {
     set_last_op_flags(CEPH_OSD_OP_FLAG_FAILOK);
   }
 
-  void dup(std::vector<OSDOp>& sops) {
-    ops = sops;
+  template<typename V>
+  void dup(V& sops) {
+    ops.clear();
+    std::copy(sops.begin(), sops.end(),
+             std::back_inserter(ops));
     out_bl.resize(sops.size());
     out_handler.resize(sops.size());
     out_rval.resize(sops.size());
@@ -1604,6 +1614,7 @@ inline std::ostream& operator <<(std::ostream& m, const ObjectOperation& oo) {
 // ----------------
 
 class Objecter : public md_config_obs_t, public Dispatcher {
+  using MOSDOp = _mosdop::MOSDOp<osdc_opvec>;
 public:
   using OpSignature = void(boost::system::error_code);
   using OpCompletion = ceph::async::Completion<OpSignature>;
@@ -1871,18 +1882,21 @@ public:
     ConnectionRef con = nullptr;  // for rx buffer only
     uint64_t features = CEPH_FEATURES_SUPPORTED_DEFAULT; // explicitly specified op features
 
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
 
     snapid_t snapid = CEPH_NOSNAP;
     SnapContext snapc;
     ceph::real_time mtime;
 
     ceph::buffer::list *outbl = nullptr;
-    std::vector<ceph::buffer::list*> out_bl;
-    std::vector<fu2::unique_function<void(boost::system::error_code, int,
-                                         const ceph::buffer::list& bl) &&>> out_handler;
-    std::vector<int*> out_rval;
-    std::vector<boost::system::error_code*> out_ec;
+    boost::container::small_vector<ceph::buffer::list*, osdc_opvec_len> out_bl;
+    boost::container::small_vector<
+      fu2::unique_function<void(boost::system::error_code, int,
+                               const ceph::buffer::list& bl) &&>,
+      osdc_opvec_len> out_handler;
+    boost::container::small_vector<int*, osdc_opvec_len> out_rval;
+    boost::container::small_vector<boost::system::error_code*,
+                                  osdc_opvec_len> out_ec;
 
     int priority = 0;
     using OpSig = void(boost::system::error_code);
@@ -1951,7 +1965,7 @@ public:
       complete(std::move(onfinish), ec, r);
     }
 
-    Op(const object_t& o, const object_locator_t& ol, vector<OSDOp>&& _ops,
+    Op(const object_t& o, const object_locator_t& ol,  osdc_opvec&& _ops,
        int f, std::unique_ptr<OpComp>&& fin,
        version_t *ov, int *offset = nullptr,
        ZTracer::Trace *parent_trace = nullptr) :
@@ -1971,7 +1985,8 @@ public:
         trace.event("start");
       }
     }
-    Op(const object_t& o, const object_locator_t& ol, vector<OSDOp>&& _ops,
+
+    Op(const object_t& o, const object_locator_t& ol, osdc_opvec&& _ops,
        int f, Context* fin, version_t *ov, int *offset = nullptr,
        ZTracer::Trace *parent_trace = nullptr) :
       target(o, ol, f),
@@ -1991,7 +2006,7 @@ public:
       }
     }
 
-    Op(const object_t& o, const object_locator_t& ol,  vector<OSDOp>&& _ops,
+    Op(const object_t& o, const object_locator_t& ol, osdc_opvec&&  _ops,
        int f, fu2::unique_function<OpSig>&& fin, version_t *ov, int *offset = nullptr,
        ZTracer::Trace *parent_trace = nullptr) :
       target(o, ol, f),
@@ -2238,7 +2253,7 @@ public:
     SnapContext snapc;
     ceph::real_time mtime;
 
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     ceph::buffer::list inbl;
     version_t *pobjver{nullptr};
 
@@ -2519,7 +2534,7 @@ private:
    * and returned whenever an op is removed from the std::map
    * If throttle_op needs to throttle it will unlock client_lock.
    */
-  int calc_op_budget(const std::vector<OSDOp>& ops);
+  int calc_op_budget(const boost::container::small_vector_base<OSDOp>& ops);
   void _throttle_op(Op *op, ceph::shunique_lock<ceph::shared_mutex>& sul,
                    int op_size = 0);
   int _take_op_budget(Op *op, ceph::shunique_lock<ceph::shared_mutex>& sul) {
@@ -2943,7 +2958,7 @@ public:
     o->priority = op.priority;
     o->snapid = snapid;
     o->outbl = pbl;
-    if (!o->outbl && op.size() == 1 && op.out_bl[0]->length())
+    if (!o->outbl && op.size() == 1 && op.out_bl[0] && op.out_bl[0]->length())
        o->outbl = op.out_bl[0];
     o->out_bl.swap(op.out_bl);
     o->out_handler.swap(op.out_handler);
@@ -2979,8 +2994,10 @@ public:
     o->priority = op.priority;
     o->snapid = snapid;
     o->outbl = pbl;
-    if (!o->outbl && op.size() == 1 && op.out_bl[0]->length())
-       o->outbl = op.out_bl[0];
+    // XXX
+    if (!o->outbl && op.size() == 1 && op.out_bl[0] && op.out_bl[0]->length()) {
+      o->outbl = op.out_bl[0];
+    }
     o->out_bl.swap(op.out_bl);
     o->out_handler.swap(op.out_handler);
     o->out_rval.swap(op.out_rval);
@@ -3111,7 +3128,8 @@ public:
    * @param extra_ops pointer to [array of] initial op[s]
    * @return index of final op (for caller to fill in)
    */
-  int init_ops(std::vector<OSDOp>& ops, int ops_count, ObjectOperation *extra_ops) {
+  int init_ops(boost::container::small_vector_base<OSDOp>& ops, int ops_count,
+              ObjectOperation *extra_ops) {
     int i;
     int extra = 0;
 
@@ -3134,7 +3152,7 @@ public:
     snapid_t snap, uint64_t *psize, ceph::real_time *pmtime,
     int flags, Context *onfinish, version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_STAT;
     C_Stat *fin = new C_Stat(psize, pmtime, onfinish);
@@ -3162,7 +3180,7 @@ public:
     int flags, Context *onfinish, version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL, int op_flags = 0,
     ZTracer::Trace *parent_trace = nullptr) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_READ;
     ops[i].op.extent.offset = off;
@@ -3194,7 +3212,7 @@ public:
     uint64_t off, ceph::buffer::list &cmp_bl,
     snapid_t snap, int flags, Context *onfinish, version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL, int op_flags = 0) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_CMPEXT;
     ops[i].op.extent.offset = off;
@@ -3227,7 +3245,7 @@ public:
                        __u32 trunc_seq, Context *onfinish,
                        version_t *objver = NULL,
                        ObjectOperation *extra_ops = NULL, int op_flags = 0) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_READ;
     ops[i].op.extent.offset = off;
@@ -3247,7 +3265,7 @@ public:
                    uint64_t off, uint64_t len, snapid_t snap, ceph::buffer::list *pbl,
                    int flags, Context *onfinish, version_t *objver = NULL,
                    ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_MAPEXT;
     ops[i].op.extent.offset = off;
@@ -3266,7 +3284,7 @@ public:
             const char *name, snapid_t snap, ceph::buffer::list *pbl, int flags,
             Context *onfinish,
             version_t *objver = NULL, ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_GETXATTR;
     ops[i].op.xattr.name_len = (name ? strlen(name) : 0);
@@ -3286,7 +3304,7 @@ public:
                       snapid_t snap, std::map<std::string,ceph::buffer::list>& attrset,
                       int flags, Context *onfinish, version_t *objver = NULL,
                       ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_GETXATTRS;
     C_GetAttrs *fin = new C_GetAttrs(attrset, onfinish);
@@ -3310,7 +3328,8 @@ public:
 
   // writes
   ceph_tid_t _modify(const object_t& oid, const object_locator_t& oloc,
-                    std::vector<OSDOp>& ops, ceph::real_time mtime,
+                    osdc_opvec& ops,
+                    ceph::real_time mtime,
                     const SnapContext& snapc, int flags,
                     Context *oncommit,
                     version_t *objver = NULL) {
@@ -3329,7 +3348,7 @@ public:
     Context *oncommit, version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL, int op_flags = 0,
     ZTracer::Trace *parent_trace = nullptr) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_WRITE;
     ops[i].op.extent.offset = off;
@@ -3364,7 +3383,7 @@ public:
     Context *oncommit,
     version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_APPEND;
     ops[i].op.extent.offset = 0;
@@ -3398,7 +3417,7 @@ public:
                         Context *oncommit,
                         version_t *objver = NULL,
                         ObjectOperation *extra_ops = NULL, int op_flags = 0) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_WRITE;
     ops[i].op.extent.offset = off;
@@ -3421,7 +3440,7 @@ public:
     ceph::real_time mtime, int flags,
     Context *oncommit, version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL, int op_flags = 0) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_WRITEFULL;
     ops[i].op.extent.offset = 0;
@@ -3454,7 +3473,7 @@ public:
     Context *oncommit, version_t *objver = NULL,
     ObjectOperation *extra_ops = NULL, int op_flags = 0) {
 
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_WRITESAME;
     ops[i].op.writesame.offset = off;
@@ -3489,7 +3508,7 @@ public:
                   uint64_t trunc_size, __u32 trunc_seq,
                   Context *oncommit, version_t *objver = NULL,
                   ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_TRUNCATE;
     ops[i].op.extent.offset = trunc_size;
@@ -3507,7 +3526,7 @@ public:
                  uint64_t off, uint64_t len, const SnapContext& snapc,
                  ceph::real_time mtime, int flags, Context *oncommit,
             version_t *objver = NULL, ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_ZERO;
     ops[i].op.extent.offset = off;
@@ -3525,7 +3544,7 @@ public:
                             ceph::real_time mtime, Context *oncommit,
                             version_t *objver = NULL,
                             ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_ROLLBACK;
     ops[i].op.snap.snapid = snapid;
@@ -3541,7 +3560,7 @@ public:
                    int create_flags, Context *oncommit,
                    version_t *objver = NULL,
                    ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_CREATE;
     ops[i].op.flags = create_flags;
@@ -3558,7 +3577,7 @@ public:
     const SnapContext& snapc, ceph::real_time mtime, int flags,
     Context *oncommit,
     version_t *objver = NULL, ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_DELETE;
     Op *o = new Op(oid, oloc, std::move(ops), flags | global_op_flags |
@@ -3584,7 +3603,7 @@ public:
              ceph::real_time mtime, int flags,
              Context *oncommit,
              version_t *objver = NULL, ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_SETXATTR;
     ops[i].op.xattr.name_len = (name ? strlen(name) : 0);
@@ -3606,7 +3625,7 @@ public:
              ceph::real_time mtime, int flags,
              Context *oncommit,
              version_t *objver = NULL, ObjectOperation *extra_ops = NULL) {
-    std::vector<OSDOp> ops;
+    osdc_opvec ops;
     int i = init_ops(ops, 1, extra_ops);
     ops[i].op.op = CEPH_OSD_OP_RMXATTR;
     ops[i].op.xattr.name_len = (name ? strlen(name) : 0);