osd/scrubber: Add a function to calculate scrub cost for mClock

With mClock scheduler, we need the cost of an operation to represent the size of an operation. This function will calculate the average object size of the PG that needs to be scrubbed and return it as the scrub cost.

Signed-off-by: Aishwarya Mathuria <amathuri@redhat.com>
(cherry picked from commit c269f352e538b795858b963644a05a65a04b6a8e)

diff --git a/src/osd/scrubber/pg_scrubber.cc b/src/osd/scrubber/pg_scrubber.cc
index 9fe7295201d69036bd0879df6d1f01ce92659e43..916d4c4fef903c4c28968b71f8d65f7ab6629902 100644 (file)
--- a/src/osd/scrubber/pg_scrubber.cc
+++ b/src/osd/scrubber/pg_scrubber.cc
@@ -876,8 +876,11 @@ int PgScrubber::get_whoami() const
  * - m_max_end
  * - end
  * - start
+ * returns:
+ * - std::nullopt if the range is blocked
+ * - otherwise, the number of objects in the selected range
  */
-bool PgScrubber::select_range()
+std::optional<uint64_t> PgScrubber::select_range()
 {
   m_be->new_chunk();
 
@@ -959,7 +962,7 @@ bool PgScrubber::select_range()
     // we'll be requeued by whatever made us unavailable for scrub
     dout(10) << __func__ << ": scrub blocked somewhere in range "
             << "[" << m_start << ", " << candidate_end << ")" << dendl;
-    return false;
+    return std::nullopt;
   }
 
   m_end = candidate_end;
@@ -972,9 +975,9 @@ bool PgScrubber::select_range()
   // debug: be 'blocked' if told so by the 'pg scrub_debug block' asok command
   if (m_debug_blockrange > 0) {
     m_debug_blockrange--;
-    return false;
+    return std::nullopt;
   }
-  return true;
+  return objects.size();
 }
 
 void PgScrubber::select_range_n_notify()
@@ -985,7 +988,6 @@ void PgScrubber::select_range_n_notify()
     // the next chunk to handle is not blocked
     dout(20) << __func__ << ": selection OK" << dendl;
     m_osds->queue_scrub_chunk_free(m_pg, Scrub::scrub_prio_t::low_priority);
-
   } else {
     // we will wait for the objects range to become available for scrubbing
     dout(10) << __func__ << ": selected chunk is busy" << dendl;
@@ -994,6 +996,28 @@ void PgScrubber::select_range_n_notify()
   }
 }
 
+uint64_t PgScrubber::get_scrub_cost(uint64_t num_chunk_objects)
+{
+  const auto& conf = m_pg->get_cct()->_conf;
+  if (op_queue_type_t::WeightedPriorityQueue == m_osds->osd->osd_op_queue_type()) {
+    // if the osd_op_queue is WPQ, we will use the default osd_scrub_cost value
+    return conf->osd_scrub_cost;
+  }
+  uint64_t cost = 0;
+  double scrub_metadata_cost = m_osds->get_cost_per_io();
+  if (m_is_deep) {
+    auto pg_avg_object_size = m_pg->get_average_object_size();
+    cost = conf->osd_scrub_event_cost + (num_chunk_objects
+    * (scrub_metadata_cost + pg_avg_object_size));
+    dout(20) << fmt::format("{} : deep-scrub cost = {}", __func__, cost) << dendl;
+    return cost;
+  } else {
+    cost = conf->osd_scrub_event_cost + (num_chunk_objects *  scrub_metadata_cost);
+    dout(20) << fmt::format("{} : shallow-scrub cost = {}", __func__, cost) << dendl;
+    return cost;
+  }
+}
+
 bool PgScrubber::write_blocked_by_scrub(const hobject_t& soid)
 {
   if (soid < m_start || soid >= m_end) {

diff --git a/src/osd/scrubber/pg_scrubber.h b/src/osd/scrubber/pg_scrubber.h
index 78e8ba90d449ee385161e6dce159383accbe4246..44f1f1abdd9376da702f926f9e71084c60ad6081 100644 (file)
--- a/src/osd/scrubber/pg_scrubber.h
+++ b/src/osd/scrubber/pg_scrubber.h
@@ -729,6 +729,8 @@ class PgScrubber : public ScrubPgIF,
   /// Returns epoch of current osdmap
   epoch_t get_osdmap_epoch() const { return get_osdmap()->get_epoch(); }
 
+  uint64_t get_scrub_cost(uint64_t num_chunk_objects);
+
   // collected statistics
   int m_shallow_errors{0};
   int m_deep_errors{0};
@@ -802,8 +804,11 @@ class PgScrubber : public ScrubPgIF,
    * - handling some head/clones issues
    *
    * The selected range is set directly into 'm_start' and 'm_end'
+   *
+   * Returns std::nullopt if the range is busy otherwise returns the
+   * number of objects in the range.
    */
-  bool select_range();
+  std::optional<uint64_t> select_range();
 
   std::list<Context*> m_callbacks;