src/ipc/mem/PagePool.cc

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section 54    Interprocess Communication
   5  *
   6  */
   7
   8 #include "squid.h"
   9 #include "base/TextException.h"
  10 #include "ipc/mem/Page.h"
  11 #include "ipc/mem/PagePool.h"
  12
  13
  14 // Ipc::Mem::PagePool
  15
  16 Ipc::Mem::PagePool::Owner *
  17 Ipc::Mem::PagePool::Init(const char *const id, const unsigned int capacity, const size_t pageSize)
  18 {
  19     static uint32_t LastPagePoolId = 0;
  20     if (++LastPagePoolId == 0)
  21         ++LastPagePoolId; // skip zero pool id
  22     return shm_new(PageStack)(id, LastPagePoolId, capacity, pageSize);
  23 }
  24
  25 Ipc::Mem::PagePool::PagePool(const char *const id):
  26         pageIndex(shm_old(PageStack)(id)),
  27         theLevels(reinterpret_cast<Atomic::Word *>(
  28                       reinterpret_cast<char *>(pageIndex.getRaw()) +
  29                       pageIndex->stackSize())),
  30         theBuf(reinterpret_cast<char *>(theLevels + PageId::maxPurpose))
  31 {
  32 }
  33
  34 size_t
  35 Ipc::Mem::PagePool::level(const int purpose) const
  36 {
  37     Must(0 <= purpose && purpose < PageId::maxPurpose);
  38     return theLevels[purpose];
  39 }
  40
  41 bool
  42 Ipc::Mem::PagePool::get(const PageId::Purpose purpose, PageId &page)
  43 {
  44     Must(0 <= purpose && purpose < PageId::maxPurpose);
  45     if (pageIndex->pop(page)) {
  46         page.purpose = purpose;
  47         ++theLevels[purpose];
  48         return true;
  49     }
  50     return false;
  51 }
  52
  53 void
  54 Ipc::Mem::PagePool::put(PageId &page)
  55 {
  56     if (!page)
  57         return;
  58
  59     Must(0 <= page.purpose && page.purpose < PageId::maxPurpose);
  60     --theLevels[page.purpose];
  61     page.purpose = PageId::maxPurpose;
  62     return pageIndex->push(page);
  63 }
  64
  65 char *
  66 Ipc::Mem::PagePool::pagePointer(const PageId &page)
  67 {
  68     Must(pageIndex->pageIdIsValid(page));
  69     return theBuf + pageSize() * (page.number - 1);
  70 }