src/ipc/mem/Pages.cc

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section 54    Interprocess Communication
   5  *
   6  */
   7
   8 #include "config.h"
   9 #include "base/TextException.h"
  10 #include "base/RunnersRegistry.h"
  11 #include "ipc/mem/PagePool.h"
  12 #include "ipc/mem/Pages.h"
  13 #include "structs.h"
  14 #include "SwapDir.h"
  15
  16 // Uses a single PagePool instance, for now.
  17 // Eventually, we may have pools dedicated to memory caching, disk I/O, etc.
  18
  19 // TODO: make pool id more unique so it does not conflict with other Squids?
  20 static const char *PagePoolId = "squid-page-pool";
  21 static Ipc::Mem::PagePool *ThePagePool = 0;
  22
  23 // TODO: make configurable to avoid waste when mem-cached objects are small/big
  24 size_t
  25 Ipc::Mem::PageSize() {
  26     return 32*1024;
  27 }
  28
  29 void
  30 Ipc::Mem::Init()
  31 {
  32     Must(!ThePagePool);
  33     const size_t capacity = Limit() / PageSize();
  34     ThePagePool = new PagePool(PagePoolId, capacity, PageSize());
  35 }
  36
  37 void
  38 Ipc::Mem::Attach()
  39 {
  40     Must(!ThePagePool);
  41     // TODO: make pool id more unique so it does not conflict with other Squid instances?
  42     ThePagePool = new PagePool(PagePoolId);
  43 }
  44
  45 bool
  46 Ipc::Mem::GetPage(PageId &page)
  47 {
  48     return ThePagePool ? ThePagePool->get(page) : false;
  49 }
  50
  51 void
  52 Ipc::Mem::PutPage(PageId &page)
  53 {
  54     Must(ThePagePool);
  55     ThePagePool->put(page);
  56 }
  57
  58 void *
  59 Ipc::Mem::PagePointer(const PageId &page)
  60 {
  61     Must(ThePagePool);
  62     return ThePagePool->pagePointer(page);
  63 }
  64
  65 size_t
  66 Ipc::Mem::Limit()
  67 {
  68     // TODO: adjust cache_mem description to say that in SMP mode,
  69     // in-transit objects are not allocated using cache_mem. Eventually,
  70     // they should not use cache_mem even if shared memory is not used:
  71     // in-transit objects have nothing to do with caching.
  72     return Config.memMaxSize;
  73 }
  74
  75 // TODO: Implement size_t Ipc::Mem::Level()
  76
  77
  78 /// initializes shared memory pages
  79 class SharedMemPagesRr: public RegisteredRunner
  80 {
  81 public:
  82     /* RegisteredRunner API */
  83     virtual void run(const RunnerRegistry &);
  84     // TODO: cleanup in destructor
  85 };
  86
  87 RunnerRegistrationEntry(rrAfterConfig, SharedMemPagesRr);
  88
  89
  90 void SharedMemPagesRr::run(const RunnerRegistry &)
  91 {
  92     // XXX: restore if (!UsingSmp()) return;
  93
  94     // When cache_dirs start using shared memory pages, they would
  95     // need to communicate their needs to us somehow.
  96     if (!Ipc::Mem::Limit())
  97         return;
  98
  99     if (IamMasterProcess())
 100         Ipc::Mem::Init();
 101     else
 102         Ipc::Mem::Attach();
 103 }