src/ipc/mem/Pages.h

   1 /*
   2  * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_IPC_MEM_PAGES_H
  10 #define SQUID_IPC_MEM_PAGES_H
  11
  12 #include "ipc/mem/Page.h"
  13
  14 namespace Ipc
  15 {
  16
  17 namespace Mem
  18 {
  19
  20 /* Single page manipulation */
  21
  22 /// sets page ID and returns true unless no free pages are found
  23 bool GetPage(const PageId::Purpose purpose, PageId &page);
  24
  25 /// makes identified page available as a free page to future GetPage() callers
  26 void PutPage(PageId &page);
  27
  28 /// converts page handler into a temporary writeable shared memory pointer
  29 char *PagePointer(const PageId &page);
  30
  31 /* Limits and statistics */
  32
  33 /// the total number of shared memory pages that can be in use at any time
  34 size_t PageLimit();
  35
  36 /// the total number of shared memory pages that can be in use at any
  37 /// time for given purpose
  38 size_t PageLimit(const int purpose);
  39
  40 /// approximate total number of shared memory pages used now
  41 size_t PageLevel();
  42
  43 /// approximate total number of shared memory pages used now for given purpose
  44 size_t PageLevel(const int purpose);
  45
  46 /// approximate total number of shared memory pages we can allocate now
  47 inline size_t PagesAvailable() { return PageLimit() - PageLevel(); }
  48
  49 /// approximate total number of shared memory pages we can allocate
  50 /// now for given purpose
  51 inline size_t PagesAvailable(const int purpose) { return PageLimit(purpose) - PageLevel(purpose); }
  52
  53 /// returns page size in bytes; all pages are assumed to be the same size
  54 size_t PageSize();
  55
  56 /// claim the need for a number of pages for a given purpose
  57 void NotePageNeed(const int purpose, const int count);
  58
  59 } // namespace Mem
  60
  61 } // namespace Ipc
  62
  63 #endif // SQUID_IPC_MEM_PAGES_H
  64