Merge pull request #20320 from rzarzynski/wip-common-md_config_cacher_t

common: introduce md_config_cacher_t

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

src/common/config_cacher.h

@@ -0,0 +1,59 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef CEPH_CONFIG_CACHER_H
+#define CEPH_CONFIG_CACHER_H
+
+#include "common/config_obs.h"
+#include "common/config.h"
+
+template <typename ValueT>
+class md_config_cacher_t : public md_config_obs_t {
+  md_config_t& conf;
+  const char* const option_name;
+  std::atomic<ValueT> value_cache;
+
+  const char** get_tracked_conf_keys() const override {
+    const static char* keys[] = { option_name, nullptr };
+    return keys;
+  }
+
+  void handle_conf_change(const md_config_t* conf,
+                          const std::set<std::string>& changed) override {
+    if (changed.count(option_name)) {
+      value_cache.store(conf->get_val<ValueT>(option_name));
+    }
+  }
+
+public:
+  md_config_cacher_t(md_config_t& conf,
+                     const char* const option_name)
+    : conf(conf),
+      option_name(option_name) {
+    conf.add_observer(this);
+    std::atomic_init(&value_cache,
+                     conf.get_val<ValueT>(option_name));
+  }
+
+  ~md_config_cacher_t() {
+    conf.remove_observer(this);
+  }
+
+  operator ValueT() const {
+    return value_cache.load();
+  }
+};
+
+#endif // CEPH_CONFIG_CACHER_H
+

src/osd/OSD.cc

@@ -215,6 +215,8 @@ OSDService::OSDService(OSD *osd) :
   recovery_gen_wq("recovery_gen_wq", cct->_conf->osd_recovery_thread_timeout,
 		  &osd->disk_tp),
   class_handler(osd->class_handler),
+  osd_max_object_size(*cct->_conf, "osd_max_object_size"),
+  osd_skip_data_digest(*cct->_conf, "osd_skip_data_digest"),
   pg_epoch_lock("OSDService::pg_epoch_lock"),
   publish_lock("OSDService::publish_lock"),
   pre_publish_lock("OSDService::pre_publish_lock"),

src/osd/OSD.h

@@ -25,6 +25,7 @@
 #include "common/WorkQueue.h"
 #include "common/AsyncReserver.h"
 #include "common/ceph_context.h"
+#include "common/config_cacher.h"
 #include "common/zipkin_trace.h"
 
 #include "mgr/MgrClient.h"
@@ -260,6 +261,9 @@ class OSDService {
   GenContextWQ recovery_gen_wq;
   ClassHandler  *&class_handler;
 
+  md_config_cacher_t<uint64_t> osd_max_object_size;
+  md_config_cacher_t<bool> osd_skip_data_digest;
+
   void enqueue_back(OpQueueItem&& qi);
   void enqueue_front(OpQueueItem&& qi);
 

src/osd/PrimaryLogPG.cc

@@ -5491,9 +5491,8 @@ int PrimaryLogPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
   ObjectState& obs = ctx->new_obs;
   object_info_t& oi = obs.oi;
   const hobject_t& soid = oi.soid;
-  bool skip_data_digest = osd->store->has_builtin_csum() &&
-    cct->_conf->osd_skip_data_digest;
-  const uint64_t osd_max_object_size = cct->_conf->osd_max_object_size;
+  const bool skip_data_digest = osd->store->has_builtin_csum() &&
+    osd->osd_skip_data_digest;
 
   PGTransaction* t = ctx->op_t.get();
 
@@ -5552,9 +5551,9 @@ int PrimaryLogPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
     // munge ZERO -> TRUNCATE?  (don't munge to DELETE or we risk hosing attributes)
     if (op.op == CEPH_OSD_OP_ZERO &&
         obs.exists &&
-        op.extent.offset < osd_max_object_size &&
+        op.extent.offset < osd->osd_max_object_size &&
         op.extent.length >= 1 &&
-        op.extent.length <= osd_max_object_size &&
+        op.extent.length <= osd->osd_max_object_size &&
 	op.extent.offset + op.extent.length >= oi.size) {
       if (op.extent.offset >= oi.size) {
         // no-op
@@ -6254,7 +6253,7 @@ int PrimaryLogPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
 	  }
 	}
 	result = check_offset_and_length(op.extent.offset, op.extent.length,
-          osd_max_object_size, get_dpp());
+          osd->osd_max_object_size, get_dpp());
 	if (result < 0)
 	  break;
 
@@ -6300,7 +6299,7 @@ int PrimaryLogPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
 	  break;
 	}
 	result = check_offset_and_length(0, op.extent.length,
-          osd_max_object_size, get_dpp());
+          osd->osd_max_object_size, get_dpp());
 	if (result < 0)
 	  break;
 
@@ -6346,7 +6345,7 @@ int PrimaryLogPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
       ++ctx->num_write;
       { // zero
 	result = check_offset_and_length(op.extent.offset, op.extent.length,
-          osd_max_object_size, get_dpp());
+          osd->osd_max_object_size, get_dpp());
 	if (result < 0)
 	  break;
 
@@ -6411,7 +6410,7 @@ int PrimaryLogPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
 	}
 
         result = check_offset_and_length(op.extent.offset, op.extent.length,
-          osd_max_object_size, get_dpp());
+          osd->osd_max_object_size, get_dpp());
         if (result < 0)
 	  break;