From: Haomai Wang <haomaiwang@gmail.com>
Date: Wed, 17 Jun 2015 14:04:52 +0000 (+0800)
Subject: librbd: Add option to allow disabling issuing alloc hint
X-Git-Tag: v9.0.3~149^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F4983%2Fhead;p=ceph.git

librbd: Add option to allow disabling issuing alloc hint

For HDD osd backend, a alloc hint is good for local filesystem to ensure
extent continuous. But for SSD, the available capacity is useful and
precious, user may not expect lots of capacity is used by reserving.
Then ssd is good for random rw.

Signed-off-by: Haomai Wang <haomaiwang@gmail.com>
---

diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index d762a2c9de3..e59560ec9d5 100644
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -897,6 +897,7 @@ OPTION(rbd_blacklist_on_break_lock, OPT_BOOL, true) // whether to blacklist clie
 OPTION(rbd_blacklist_expire_seconds, OPT_INT, 0) // number of seconds to blacklist - set to 0 for OSD default
 OPTION(rbd_request_timed_out_seconds, OPT_INT, 30) // number of seconds before maint request times out
 OPTION(rbd_skip_partial_discard, OPT_BOOL, false) // when trying to discard a range inside an object, set to true to skip zeroing the range.
+OPTION(rbd_enable_alloc_hint, OPT_BOOL, true) // when writing a object, it will issue a hint to osd backend to indicate the expected size object need
 
 /*
  * The following options change the behavior for librbd's image creation methods that
diff --git a/src/librbd/AioRequest.cc b/src/librbd/AioRequest.cc
index 77ead571a4b..558fa0131a4 100644
--- a/src/librbd/AioRequest.cc
+++ b/src/librbd/AioRequest.cc
@@ -497,7 +497,8 @@ namespace librbd {
   }
 
   void AioWrite::add_write_ops(librados::ObjectWriteOperation *wr) {
-    wr->set_alloc_hint(m_ictx->get_object_size(), m_ictx->get_object_size());
+    if (m_ictx->enable_alloc_hint)
+      wr->set_alloc_hint(m_ictx->get_object_size(), m_ictx->get_object_size());
     wr->write(m_object_off, m_write_data);
     wr->set_op_flags2(m_op_flags);
   }
diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index 7f74ec01869..7637c852ca2 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -931,5 +931,6 @@ public:
     ASSIGN_OPTION(blacklist_on_break_lock);
     ASSIGN_OPTION(blacklist_expire_seconds);
     ASSIGN_OPTION(request_timed_out_seconds);
+    ASSIGN_OPTION(enable_alloc_hint);
   }
 }
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index 3d8d1f943a1..053ff61408e 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -157,6 +157,7 @@ namespace librbd {
     bool blacklist_on_break_lock;
     uint32_t blacklist_expire_seconds;
     uint32_t request_timed_out_seconds;
+    bool enable_alloc_hint;
     static bool _filter_metadata_confs(const string &prefix, std::map<string, bool> &configs,
                                        map<string, bufferlist> &pairs, map<string, bufferlist> *res);