From 5f7f6c3c6aa3640162e5dc91d4e648b2c17e74d2 Mon Sep 17 00:00:00 2001
From: Jason Dillaman <dillaman@redhat.com>
Date: Wed, 8 Apr 2015 17:24:08 -0400
Subject: [PATCH 14/22] librbd: add task pool / work queue for AIO requests

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit afb896d91f886b647baf38f7ec94cc3739f6d2a9)
(cherry picked from commit 9faaeae4c181944636b4119c0a797181ded0651f)

Conflicts:
	src/librbd/ImageCtx.cc: removed refs to pending AIO
	src/librbd/ImageCtx.h: removed refs to pending AIO
	src/librbd/internal.cc: removed refs to pending AIO
---
 src/common/config_opts.h |  2 ++
 src/librbd/ImageCtx.cc   | 30 +++++++++++++++++++++++++++++-
 src/librbd/ImageCtx.h    |  3 +++
 src/librbd/internal.cc   |  4 ++++
 4 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index da9bcdf..f024011 100644
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -719,6 +719,8 @@ OPTION(journal_ignore_corruption, OPT_BOOL, false) // assume journal is not corr
 OPTION(rados_mon_op_timeout, OPT_DOUBLE, 0) // how many seconds to wait for a response from the monitor before returning an error from a rados operation. 0 means on limit.
 OPTION(rados_osd_op_timeout, OPT_DOUBLE, 0) // how many seconds to wait for a response from osds before returning an error from a rados operation. 0 means no limit.
 
+OPTION(rbd_op_threads, OPT_INT, 1)
+OPTION(rbd_op_thread_timeout, OPT_INT, 60)
 OPTION(rbd_cache, OPT_BOOL, false) // whether to enable caching (writeback unless rbd_cache_max_dirty is 0)
 OPTION(rbd_cache_writethrough_until_flush, OPT_BOOL, false) // whether to make writeback caching writethrough until flush is called, to be sure the user of librbd will send flushs so that writeback is safe
 OPTION(rbd_cache_size, OPT_LONGLONG, 32<<20)         // cache size in bytes
diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index b5c2db6..4850b9a 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -6,6 +6,7 @@
 #include "common/dout.h"
 #include "common/errno.h"
 #include "common/perf_counters.h"
+#include "common/WorkQueue.h"
 
 #include "librbd/internal.h"
 #include "librbd/WatchCtx.h"
@@ -27,6 +28,23 @@ using librados::snap_t;
 using librados::IoCtx;
 
 namespace librbd {
+
+namespace {
+
+class ThreadPoolSingleton : public ThreadPool {
+public:
+  ThreadPoolSingleton(CephContext *cct)
+    : ThreadPool(cct, "librbd::thread_pool", cct->_conf->rbd_op_threads,
+                 "rbd_op_threads") {
+    start();
+  }
+  virtual ~ThreadPoolSingleton() {
+    stop();
+  }
+};
+
+} // anonymous namespace
+
   ImageCtx::ImageCtx(const string &image_name, const string &image_id,
 		     const char *snap, IoCtx& p, bool ro)
     : cct((CephContext*)p.cct()),
@@ -51,7 +69,8 @@ namespace librbd {
       format_string(NULL),
       id(image_id), parent(NULL),
       stripe_unit(0), stripe_count(0),
-      object_cacher(NULL), writeback_handler(NULL), object_set(NULL)
+      object_cacher(NULL), writeback_handler(NULL), object_set(NULL),
+      aio_work_queue(NULL)
   {
     md_ctx.dup(p);
     data_ctx.dup(p);
@@ -96,6 +115,13 @@ namespace librbd {
       object_set->return_enoent = true;
       object_cacher->start();
     }
+
+    ThreadPoolSingleton *thread_pool_singleton;
+    cct->lookup_or_create_singleton_object<ThreadPoolSingleton>(
+      thread_pool_singleton, "librbd::thread_pool");
+    aio_work_queue = new ContextWQ("librbd::aio_work_queue",
+                                   cct->_conf->rbd_op_thread_timeout,
+                                   thread_pool_singleton);
   }
 
   ImageCtx::~ImageCtx() {
@@ -113,6 +139,8 @@ namespace librbd {
       object_set = NULL;
     }
     delete[] format_string;
+
+    delete aio_work_queue;
   }
 
   int ImageCtx::init() {
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index 83ed044..218527a 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -25,6 +25,7 @@
 #include "librbd/parent_types.h"
 
 class CephContext;
+class ContextWQ;
 class PerfCounters;
 
 namespace librbd {
@@ -89,6 +90,8 @@ namespace librbd {
     LibrbdWriteback *writeback_handler;
     ObjectCacher::ObjectSet *object_set;
 
+    ContextWQ *aio_work_queue;
+
     /**
      * Either image_name or image_id must be set.
      * If id is not known, pass the empty std::string,
diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index afa4660..b0c8ebc 100644
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -9,6 +9,7 @@
 #include "common/dout.h"
 #include "common/errno.h"
 #include "common/Throttle.h"
+#include "common/WorkQueue.h"
 #include "cls/lock/cls_lock_client.h"
 #include "include/stringify.h"
 
@@ -2118,6 +2119,9 @@ reprotect_and_return_err:
   void close_image(ImageCtx *ictx)
   {
     ldout(ictx->cct, 20) << "close_image " << ictx << dendl;
+
+    ictx->aio_work_queue->drain();
+
     if (ictx->object_cacher)
       ictx->shutdown_cache(); // implicitly flushes
     else
-- 
2.1.0