ceph/src/rocksdb/db/blob/blob_file_cache.cc

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 #include "db/blob/blob_file_cache.h"
   7
   8 #include <cassert>
   9 #include <memory>
  10
  11 #include "db/blob/blob_file_reader.h"
  12 #include "options/cf_options.h"
  13 #include "rocksdb/cache.h"
  14 #include "rocksdb/slice.h"
  15 #include "test_util/sync_point.h"
  16 #include "trace_replay/io_tracer.h"
  17 #include "util/hash.h"
  18
  19 namespace ROCKSDB_NAMESPACE {
  20
  21 BlobFileCache::BlobFileCache(Cache* cache,
  22                              const ImmutableOptions* immutable_options,
  23                              const FileOptions* file_options,
  24                              uint32_t column_family_id,
  25                              HistogramImpl* blob_file_read_hist,
  26                              const std::shared_ptr<IOTracer>& io_tracer)
  27     : cache_(cache),
  28       mutex_(kNumberOfMutexStripes, kGetSliceNPHash64UnseededFnPtr),
  29       immutable_options_(immutable_options),
  30       file_options_(file_options),
  31       column_family_id_(column_family_id),
  32       blob_file_read_hist_(blob_file_read_hist),
  33       io_tracer_(io_tracer) {
  34   assert(cache_);
  35   assert(immutable_options_);
  36   assert(file_options_);
  37 }
  38
  39 Status BlobFileCache::GetBlobFileReader(
  40     uint64_t blob_file_number,
  41     CacheHandleGuard<BlobFileReader>* blob_file_reader) {
  42   assert(blob_file_reader);
  43   assert(blob_file_reader->IsEmpty());
  44
  45   const Slice key = GetSlice(&blob_file_number);
  46
  47   assert(cache_);
  48
  49   Cache::Handle* handle = cache_->Lookup(key);
  50   if (handle) {
  51     *blob_file_reader = CacheHandleGuard<BlobFileReader>(cache_, handle);
  52     return Status::OK();
  53   }
  54
  55   TEST_SYNC_POINT("BlobFileCache::GetBlobFileReader:DoubleCheck");
  56
  57   // Check again while holding mutex
  58   MutexLock lock(mutex_.get(key));
  59
  60   handle = cache_->Lookup(key);
  61   if (handle) {
  62     *blob_file_reader = CacheHandleGuard<BlobFileReader>(cache_, handle);
  63     return Status::OK();
  64   }
  65
  66   assert(immutable_options_);
  67   Statistics* const statistics = immutable_options_->stats;
  68
  69   RecordTick(statistics, NO_FILE_OPENS);
  70
  71   std::unique_ptr<BlobFileReader> reader;
  72
  73   {
  74     assert(file_options_);
  75     const Status s = BlobFileReader::Create(
  76         *immutable_options_, *file_options_, column_family_id_,
  77         blob_file_read_hist_, blob_file_number, io_tracer_, &reader);
  78     if (!s.ok()) {
  79       RecordTick(statistics, NO_FILE_ERRORS);
  80       return s;
  81     }
  82   }
  83
  84   {
  85     constexpr size_t charge = 1;
  86
  87     const Status s = cache_->Insert(key, reader.get(), charge,
  88                                     &DeleteCacheEntry<BlobFileReader>, &handle);
  89     if (!s.ok()) {
  90       RecordTick(statistics, NO_FILE_ERRORS);
  91       return s;
  92     }
  93   }
  94
  95   reader.release();
  96
  97   *blob_file_reader = CacheHandleGuard<BlobFileReader>(cache_, handle);
  98
  99   return Status::OK();
 100 }
 101
 102 }  // namespace ROCKSDB_NAMESPACE