crimson/os/seastore/async_cleaner: rename rewrite_backref_bytes_per_cycle to max_backref_bytes_per_cycle

Unlike rewrite_dirty_bytes_per_cycle which serves as the maximum bytes
that trim_dirty can trim and create, rewrite_backref_bytes_per_cycle
only indicate the maximum bytes of new backref extents that trim_alloc
can generate. So we rename it to avoid misunderstanding.

Signed-off-by: Xuehan Xu <[email protected]>

Author: xxhdx1985126

src/crimson/os/seastore/async_cleaner.cc

@@ -348,7 +348,7 @@ void JournalTrimmerImpl::config_t::validate() const
   ceph_assert(rewrite_dirty_bytes_per_trans > 0);
   ceph_assert(rewrite_dirty_bytes_per_cycle >=
     rewrite_dirty_bytes_per_trans);
-  ceph_assert(rewrite_backref_bytes_per_cycle > 0);
+  ceph_assert(max_backref_bytes_per_cycle > 0);
 }
 
 JournalTrimmerImpl::config_t
@@ -379,7 +379,7 @@ JournalTrimmerImpl::config_t::get_default(
     max_journal_bytes,
     1<<26,// rewrite_dirty_bytes_per_cycle
     1<<17,// rewrite_dirty_bytes_per_trans
-    1<<24 // rewrite_backref_bytes_per_cycle
+    1<<24 // max_backref_bytes_per_cycle
   };
 }
 
@@ -413,7 +413,7 @@ JournalTrimmerImpl::config_t::get_test(
       ? 1<<25
       : target_dirty_bytes / 2,// rewrite_dirty_bytes_per_cycle
     1<<17,// rewrite_dirty_bytes_per_trans
-    1<<24 // rewrite_backref_bytes_per_cycle
+    1<<24 // max_backref_bytes_per_cycle
   };
 }
 
@@ -659,7 +659,7 @@ JournalTrimmerImpl::trim_alloc()
       return backref_manager.merge_cached_backrefs(
         t,
         target,
-        config.rewrite_backref_bytes_per_cycle
+        config.max_backref_bytes_per_cycle
       ).si_then([this, FNAME, &t](auto trim_alloc_to)
         -> ExtentCallbackInterface::submit_transaction_direct_iertr::future<>
       {

src/crimson/os/seastore/async_cleaner.h

@@ -517,8 +517,8 @@ class JournalTrimmerImpl : public JournalTrimmer {
     std::size_t rewrite_dirty_bytes_per_cycle = 0;
     /// Number of bytes to rewrite dirty per transaction
     std::size_t rewrite_dirty_bytes_per_trans = 0;
-    /// Number of bytes to rewrite backref per cycle
-    std::size_t rewrite_backref_bytes_per_cycle = 0;
+    /// Maximum number of bytes of new backref extents per cycle
+    std::size_t max_backref_bytes_per_cycle = 0;
 
     void validate() const;
 
@@ -566,7 +566,7 @@ class JournalTrimmerImpl : public JournalTrimmer {
       journal_seq_t dirty_tail, journal_seq_t alloc_tail) final;
 
   std::size_t get_trim_size_per_cycle() const final {
-    return config.rewrite_backref_bytes_per_cycle +
+    return config.max_backref_bytes_per_cycle +
       get_dirty_bytes_to_trim();
   }