From: xie xingguo <xie.xingguo@zte.com.cn>
Date: Tue, 14 Aug 2018 06:24:55 +0000 (+0800)
Subject: osd/PG: find_best_info - add completeness as the preferred option
X-Git-Tag: v14.0.1~435^2~5
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=4068e724ce9cc1463de0174c2ad266bec3454630;p=ceph.git

osd/PG: find_best_info - add completeness as the preferred option

Async recovery peers usually have a relative complete
log history but may exist a lot of missing objects. Choosing them
as auth_log_shard and further as primary if current up_primary is
unrecoverable, say, could have a bigger chance to block client I/Os.

Among peers with identical new log history, we now consider those
who are now complete (having no missing objects) as the preferred
ones when determining auth_log_shard.

Signed-off-by: xie xingguo <xie.xingguo@zte.com.cn>
---

diff --git a/src/osd/PG.cc b/src/osd/PG.cc
index cc6845678dd17..95c92f670f254 100644
--- a/src/osd/PG.cc
+++ b/src/osd/PG.cc
@@ -1208,6 +1208,22 @@ map<pg_shard_t, pg_info_t>::const_iterator PG::find_best_info(
       continue;
     }
 
+    if (!p->second.has_missing() && best->second.has_missing()) {
+      dout(10) << __func__ << " prefer osd." << p->first
+               << " because it is complete while best has missing"
+               << dendl;
+      best = p;
+      continue;
+    } else if (p->second.has_missing() && !best->second.has_missing()) {
+      dout(10) << __func__ << " skipping osd." << p->first
+               << " because it has missing while best is complete"
+               << dendl;
+      continue;
+    } else {
+      // both are complete or have missing
+      // fall through
+    }
+
     // prefer current primary (usually the caller), all things being equal
     if (p->first == pg_whoami) {
       dout(10) << "calc_acting prefer osd." << p->first
diff --git a/src/osd/osd_types.h b/src/osd/osd_types.h
index 455ff56d359ca..1945272bef3b0 100644
--- a/src/osd/osd_types.h
+++ b/src/osd/osd_types.h
@@ -2411,6 +2411,7 @@ struct pg_info_t {
   bool is_empty() const { return last_update.version == 0; }
   bool dne() const { return history.epoch_created == 0; }
 
+  bool has_missing() const { return last_complete != last_update; }
   bool is_incomplete() const { return !last_backfill.is_max(); }
 
   void encode(bufferlist& bl) const;