Merge pull request #24065 from jdurgin/wip-luminous-cache-autotune

luminous: os/bluestore: cache autotuning and memory limit

Reviewed-by: Sage Weil <sage@redhat.com>

src/CMakeLists.txt

@@ -537,6 +537,7 @@ set(libcommon_files
   common/dns_resolve.cc
   common/hostname.cc
   common/util.cc
+  common/PriorityCache.cc
   arch/probe.cc
   ${auth_files}
   ${mds_files})

src/common/PriorityCache.cc

@@ -0,0 +1,29 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2018 Red Hat
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#include "PriorityCache.h"
+
+namespace PriorityCache {
+  int64_t get_chunk(uint64_t usage, uint64_t chunk_bytes) {
+    // Add a chunk of headroom and round up to the near chunk
+    uint64_t val = usage + chunk_bytes;
+    uint64_t r = (val) % chunk_bytes;
+    if (r > 0)
+      val = val + chunk_bytes - r;
+    return val;
+  }
+
+  PriCache::~PriCache() {
+  }
+}

src/common/PriorityCache.h

@@ -0,0 +1,69 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2018 Red Hat
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef CEPH_PRIORITY_CACHE_H
+#define CEPH_PRIORITY_CACHE_H
+
+#include <stdint.h>
+#include <string>
+
+namespace PriorityCache {
+  enum Priority {
+    PRI0,  // Reserved for special items
+    PRI1,  // High priority cache items
+    PRI2,  // Medium priority cache items
+    PRI3,  // Low priority cache items
+    LAST = PRI3,
+  };
+
+  int64_t get_chunk(uint64_t usage, uint64_t chunk_bytes);
+
+  struct PriCache {
+    virtual ~PriCache();
+
+    /* Ask the cache to request memory for the given priority rounded up to
+     * the nearst chunk_bytes.  This for example, may return the size of all
+     * items associated with this priority plus some additional space for
+     * future growth.  Note that the cache may ultimately be allocated less 
+     * memory than it requests here.
+     */
+    virtual int64_t request_cache_bytes(PriorityCache::Priority pri, uint64_t chunk_bytes) const = 0;
+
+    // Get the number of bytes currently allocated to the given priority.
+    virtual int64_t get_cache_bytes(PriorityCache::Priority pri) const = 0;
+
+    // Get the number of bytes currently allocated to all priorities.
+    virtual int64_t get_cache_bytes() const = 0;
+
+    // Allocate bytes for a given priority.
+    virtual void set_cache_bytes(PriorityCache::Priority pri, int64_t bytes) = 0;
+
+    // Allocate additional bytes for a given priority.
+    virtual void add_cache_bytes(PriorityCache::Priority pri, int64_t bytes) = 0;
+
+    // Commit the current number of bytes allocated to the cache.
+    virtual int64_t commit_cache_size() = 0;
+
+    // Get the ratio of available memory this cache should target.
+    virtual double get_cache_ratio() const = 0;
+
+    // Set the ratio of available memory this cache should target.
+    virtual void set_cache_ratio(double ratio) = 0;
+
+    // Get the name of this cache.
+    virtual std::string get_cache_name() const = 0;
+  };
+}
+
+#endif