update ceph source to reef 18.1.2

[ceph.git] / ceph / src / rocksdb / table / block_based / block_prefetcher.cc

diff --git a/ceph/src/rocksdb/table/block_based/block_prefetcher.cc b/ceph/src/rocksdb/table/block_based/block_prefetcher.cc
index aa3fc36108ddcdf35a37c0cdcb4eac13f9a4df5d..83ec2cb060baff872864472d45719a806e75eb3a 100644 (file)
--- a/ceph/src/rocksdb/table/block_based/block_prefetcher.cc
+++ b/ceph/src/rocksdb/table/block_based/block_prefetcher.cc
@@ -8,59 +8,113 @@
 // found in the LICENSE file. See the AUTHORS file for names of contributors.
 #include "table/block_based/block_prefetcher.h"
 
+#include "rocksdb/file_system.h"
+#include "table/block_based/block_based_table_reader.h"
+
 namespace ROCKSDB_NAMESPACE {
-void BlockPrefetcher::PrefetchIfNeeded(const BlockBasedTable::Rep* rep,
-                                       const BlockHandle& handle,
-                                       size_t readahead_size,
-                                       bool is_for_compaction) {
+void BlockPrefetcher::PrefetchIfNeeded(
+    const BlockBasedTable::Rep* rep, const BlockHandle& handle,
+    const size_t readahead_size, bool is_for_compaction,
+    const bool no_sequential_checking,
+    const Env::IOPriority rate_limiter_priority) {
+  // num_file_reads is used  by FilePrefetchBuffer only when
+  // implicit_auto_readahead is set.
   if (is_for_compaction) {
-    rep->CreateFilePrefetchBufferIfNotExists(compaction_readahead_size_,
-                                             compaction_readahead_size_,
-                                             &prefetch_buffer_);
+    rep->CreateFilePrefetchBufferIfNotExists(
+        compaction_readahead_size_, compaction_readahead_size_,
+        &prefetch_buffer_, /*implicit_auto_readahead=*/false,
+        /*num_file_reads=*/0, /*num_file_reads_for_auto_readahead=*/0);
     return;
   }
 
-  // Explicit user requested readahead
+  // Explicit user requested readahead.
   if (readahead_size > 0) {
-    rep->CreateFilePrefetchBufferIfNotExists(readahead_size, readahead_size,
-                                             &prefetch_buffer_);
+    rep->CreateFilePrefetchBufferIfNotExists(
+        readahead_size, readahead_size, &prefetch_buffer_,
+        /*implicit_auto_readahead=*/false, /*num_file_reads=*/0,
+        /*num_file_reads_for_auto_readahead=*/0);
+    return;
+  }
+
+  // Implicit readahead.
+
+  // If max_auto_readahead_size is set to be 0 by user, no data will be
+  // prefetched.
+  size_t max_auto_readahead_size = rep->table_options.max_auto_readahead_size;
+  if (max_auto_readahead_size == 0 || initial_auto_readahead_size_ == 0) {
+    return;
+  }
+
+  if (initial_auto_readahead_size_ > max_auto_readahead_size) {
+    initial_auto_readahead_size_ = max_auto_readahead_size;
+  }
+
+  // In case of no_sequential_checking, it will skip the num_file_reads_ and
+  // will always creates the FilePrefetchBuffer.
+  if (no_sequential_checking) {
+    rep->CreateFilePrefetchBufferIfNotExists(
+        initial_auto_readahead_size_, max_auto_readahead_size,
+        &prefetch_buffer_, /*implicit_auto_readahead=*/true,
+        /*num_file_reads=*/0,
+        rep->table_options.num_file_reads_for_auto_readahead);
+    return;
+  }
+
+  size_t len = BlockBasedTable::BlockSizeWithTrailer(handle);
+  size_t offset = handle.offset();
+
+  // If FS supports prefetching (readahead_limit_ will be non zero in that case)
+  // and current block exists in prefetch buffer then return.
+  if (offset + len <= readahead_limit_) {
+    UpdateReadPattern(offset, len);
     return;
   }
 
+  if (!IsBlockSequential(offset)) {
+    UpdateReadPattern(offset, len);
+    ResetValues(rep->table_options.initial_auto_readahead_size);
+    return;
+  }
+  UpdateReadPattern(offset, len);
+
   // Implicit auto readahead, which will be enabled if the number of reads
-  // reached `kMinNumFileReadsToStartAutoReadahead` (default: 2).
+  // reached `table_options.num_file_reads_for_auto_readahead` (default: 2)  and
+  // scans are sequential.
   num_file_reads_++;
-  if (num_file_reads_ <=
-      BlockBasedTable::kMinNumFileReadsToStartAutoReadahead) {
+  if (num_file_reads_ <= rep->table_options.num_file_reads_for_auto_readahead) {
     return;
   }
 
   if (rep->file->use_direct_io()) {
     rep->CreateFilePrefetchBufferIfNotExists(
-        BlockBasedTable::kInitAutoReadaheadSize,
-        BlockBasedTable::kMaxAutoReadaheadSize, &prefetch_buffer_);
+        initial_auto_readahead_size_, max_auto_readahead_size,
+        &prefetch_buffer_, /*implicit_auto_readahead=*/true, num_file_reads_,
+        rep->table_options.num_file_reads_for_auto_readahead);
     return;
   }
 
-  if (handle.offset() + static_cast<size_t>(block_size(handle)) <=
-      readahead_limit_) {
-    return;
+  if (readahead_size_ > max_auto_readahead_size) {
+    readahead_size_ = max_auto_readahead_size;
   }
 
   // If prefetch is not supported, fall back to use internal prefetch buffer.
   // Discarding other return status of Prefetch calls intentionally, as
   // we can fallback to reading from disk if Prefetch fails.
-  Status s = rep->file->Prefetch(handle.offset(), readahead_size_);
+  Status s = rep->file->Prefetch(
+      handle.offset(),
+      BlockBasedTable::BlockSizeWithTrailer(handle) + readahead_size_,
+      rate_limiter_priority);
   if (s.IsNotSupported()) {
     rep->CreateFilePrefetchBufferIfNotExists(
-        BlockBasedTable::kInitAutoReadaheadSize,
-        BlockBasedTable::kMaxAutoReadaheadSize, &prefetch_buffer_);
+        initial_auto_readahead_size_, max_auto_readahead_size,
+        &prefetch_buffer_, /*implicit_auto_readahead=*/true, num_file_reads_,
+        rep->table_options.num_file_reads_for_auto_readahead);
     return;
   }
-  readahead_limit_ = static_cast<size_t>(handle.offset() + readahead_size_);
+
+  readahead_limit_ = offset + len + readahead_size_;
   // Keep exponentially increasing readahead size until
-  // kMaxAutoReadaheadSize.
-  readahead_size_ =
-      std::min(BlockBasedTable::kMaxAutoReadaheadSize, readahead_size_ * 2);
+  // max_auto_readahead_size.
+  readahead_size_ = std::min(max_auto_readahead_size, readahead_size_ * 2);
 }
 }  // namespace ROCKSDB_NAMESPACE