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Diffstat (limited to 'third_party/tcmalloc/vendor/src/span.h')
-rw-r--r-- | third_party/tcmalloc/vendor/src/span.h | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/third_party/tcmalloc/vendor/src/span.h b/third_party/tcmalloc/vendor/src/span.h new file mode 100644 index 0000000..ab9a796 --- /dev/null +++ b/third_party/tcmalloc/vendor/src/span.h @@ -0,0 +1,106 @@ +// Copyright (c) 2008, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// --- +// Author: Sanjay Ghemawat <opensource@google.com> +// +// A Span is a contiguous run of pages. + +#ifndef TCMALLOC_SPAN_H_ +#define TCMALLOC_SPAN_H_ + +#include <config.h> +#include "common.h" + +namespace tcmalloc { + +// Information kept for a span (a contiguous run of pages). +struct Span { + PageID start; // Starting page number + Length length; // Number of pages in span + Span* next; // Used when in link list + Span* prev; // Used when in link list + void* objects; // Linked list of free objects + unsigned int refcount : 16; // Number of non-free objects + unsigned int sizeclass : 8; // Size-class for small objects (or 0) + unsigned int location : 2; // Is the span on a freelist, and if so, which? + unsigned int sample : 1; // Sampled object? + +#undef SPAN_HISTORY +#ifdef SPAN_HISTORY + // For debugging, we can keep a log events per span + int nexthistory; + char history[64]; + int value[64]; +#endif + + // What freelist the span is on: IN_USE if on none, or normal or returned + enum { IN_USE, ON_NORMAL_FREELIST, ON_RETURNED_FREELIST }; +}; + +#ifdef SPAN_HISTORY +void Event(Span* span, char op, int v = 0); +#else +#define Event(s,o,v) ((void) 0) +#endif + +// Allocator/deallocator for spans +Span* NewSpan(PageID p, Length len); +void DeleteSpan(Span* span); + +// ------------------------------------------------------------------------- +// Doubly linked list of spans. +// ------------------------------------------------------------------------- + +// Initialize *list to an empty list. +void DLL_Init(Span* list); + +// Remove 'span' from the linked list in which it resides, updating the +// pointers of adjacent Spans and setting span's next and prev to NULL. +void DLL_Remove(Span* span); + +// Return true iff "list" is empty. +inline bool DLL_IsEmpty(const Span* list) { + return list->next == list; +} + +// Add span to the front of list. +void DLL_Prepend(Span* list, Span* span); + +// Return the length of the linked list. O(n) +int DLL_Length(const Span* list); + +// Print the contents of the list to stderr. +#if 0 // This isn't used. +void DLL_Print(const char* label, const Span* list); +#endif + +} // namespace tcmalloc + +#endif // TCMALLOC_SPAN_H_ |