xpcom/base/nsMemoryImpl.cpp

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  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
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  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
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  24  * Alternatively, the contents of this file may be used under the terms of
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  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #include "nsXPCOM.h"
  39 #include "nsMemoryImpl.h"
  40 #include "nsThreadUtils.h"
  41
  42 #include "nsIObserverService.h"
  43 #include "nsIServiceManager.h"
  44 #include "nsISupportsArray.h"
  45
  46 #include "prmem.h"
  47 #include "prcvar.h"
  48 #include "pratom.h"
  49
  50 #include "nsAlgorithm.h"
  51 #include "nsAutoLock.h"
  52 #include "nsCOMPtr.h"
  53 #include "nsString.h"
  54
  55 #if defined(XP_WIN)
  56 #include <windows.h>
  57 #define NS_MEMORY_FLUSHER
  58 #else
  59 // Need to implement the nsIMemory::IsLowMemory() predicate
  60 #undef NS_MEMORY_FLUSHER
  61 #endif
  62
  63 #ifdef NS_MEMORY_FLUSHER
  64 #include "nsITimer.h"
  65 #endif
  66
  67 ////////////////////////////////////////////////////////////////////////////////
  68 // Define NS_OUT_OF_MEMORY_TESTER if you want to force memory failures
  69
  70 #ifdef DEBUG_xwarren
  71 #define NS_OUT_OF_MEMORY_TESTER
  72 #endif
  73
  74 #ifdef NS_OUT_OF_MEMORY_TESTER
  75
  76 // flush memory one in this number of times:
  77 #define NS_FLUSH_FREQUENCY        100000
  78
  79 // fail allocation one in this number of flushes:
  80 #define NS_FAIL_FREQUENCY         10
  81
  82 PRUint32 gFlushFreq = 0;
  83 PRUint32 gFailFreq = 0;
  84
  85 static void*
  86 mallocator(PRSize size, PRUint32& counter, PRUint32 max)
  87 {
  88     if (counter++ >= max) {
  89         counter = 0;
  90         NS_ASSERTION(0, "about to fail allocation... watch out");
  91         return nsnull;
  92     }
  93     return PR_Malloc(size);
  94 }
  95
  96 static void*
  97 reallocator(void* ptr, PRSize size, PRUint32& counter, PRUint32 max)
  98 {
  99     if (counter++ >= max) {
 100         counter = 0;
 101         NS_ASSERTION(0, "about to fail reallocation... watch out");
 102         return nsnull;
 103     }
 104     return PR_Realloc(ptr, size);
 105 }
 106
 107 #define MALLOC1(s)       mallocator(s, gFlushFreq, NS_FLUSH_FREQUENCY)
 108 #define REALLOC1(p, s)   reallocator(p, s, gFlushFreq, NS_FLUSH_FREQUENCY)
 109
 110 #else
 111
 112 #define MALLOC1(s)       PR_Malloc(s)
 113 #define REALLOC1(p, s)   PR_Realloc(p, s)
 114
 115 #endif // NS_OUT_OF_MEMORY_TESTER
 116
 117 #if defined(XDEBUG_waterson)
 118 #define NS_TEST_MEMORY_FLUSHER
 119 #endif
 120
 121 #ifdef NS_MEMORY_FLUSHER
 122 /**
 123  * A class that is used to periodically check the status of the system,
 124  * determine if too much memory is in use, and if so, trigger a "memory flush".
 125  */
 126 class MemoryFlusher : public nsITimerCallback
 127 {
 128 public:
 129     // We don't use the generic macros because we are a special static object
 130     NS_IMETHOD QueryInterface(REFNSIID aIID, void** aResult);
 131     NS_IMETHOD_(nsrefcnt) AddRef(void) { return 2; }
 132     NS_IMETHOD_(nsrefcnt) Release(void) { return 1; }
 133
 134     NS_DECL_NSITIMERCALLBACK
 135
 136     nsresult Init();
 137     void StopAndJoin();
 138
 139 private:
 140     static PRIntervalTime sTimeout;
 141     static PRLock*        sLock;
 142     static PRCondVar*     sCVar;
 143
 144     enum {
 145         kTimeout = 60000 // milliseconds
 146     };
 147 };
 148
 149 static MemoryFlusher sGlobalMemoryFlusher;
 150
 151 #endif // NS_MEMORY_FLUSHER
 152
 153 static nsMemoryImpl sGlobalMemory;
 154
 155 NS_IMPL_QUERY_INTERFACE1(nsMemoryImpl, nsIMemory)
 156
 157 NS_IMETHODIMP_(void*)
 158 nsMemoryImpl::Alloc(PRSize size)
 159 {
 160     return NS_Alloc(size);
 161 }
 162
 163 NS_IMETHODIMP_(void*)
 164 nsMemoryImpl::Realloc(void* ptr, PRSize size)
 165 {
 166     return NS_Realloc(ptr, size);
 167 }
 168
 169 NS_IMETHODIMP_(void)
 170 nsMemoryImpl::Free(void* ptr)
 171 {
 172     NS_Free(ptr);
 173 }
 174
 175 NS_IMETHODIMP
 176 nsMemoryImpl::HeapMinimize(PRBool aImmediate)
 177 {
 178     return FlushMemory(NS_LITERAL_STRING("heap-minimize").get(), aImmediate);
 179 }
 180
 181 NS_IMETHODIMP
 182 nsMemoryImpl::IsLowMemory(PRBool *result)
 183 {
 184 #if defined(WINCE)
 185     MEMORYSTATUS stat;
 186     GlobalMemoryStatus(&stat);
 187     *result = ((float)stat.dwAvailPhys / stat.dwTotalPhys) < 0.1;
 188 #elif defined(XP_WIN)
 189     MEMORYSTATUS stat;
 190     GlobalMemoryStatus(&stat);
 191     *result = ((float)stat.dwAvailPageFile / stat.dwTotalPageFile) < 0.1;
 192 #else
 193     *result = PR_FALSE;
 194 #endif
 195     return NS_OK;
 196 }
 197
 198
 199 /*static*/ nsresult
 200 nsMemoryImpl::InitFlusher()
 201 {
 202 #ifdef NS_MEMORY_FLUSHER
 203     return sGlobalMemoryFlusher.Init();
 204 #else
 205     return NS_OK;
 206 #endif
 207 }
 208
 209 /*static*/ nsresult
 210 nsMemoryImpl::Create(nsISupports* outer, const nsIID& aIID, void **aResult)
 211 {
 212     NS_ENSURE_NO_AGGREGATION(outer);
 213     return sGlobalMemory.QueryInterface(aIID, aResult);
 214 }
 215
 216 nsresult
 217 nsMemoryImpl::FlushMemory(const PRUnichar* aReason, PRBool aImmediate)
 218 {
 219     nsresult rv;
 220
 221     if (aImmediate) {
 222         // They've asked us to run the flusher *immediately*. We've
 223         // got to be on the UI main thread for us to be able to do
 224         // that...are we?
 225         if (!NS_IsMainThread()) {
 226             NS_ERROR("can't synchronously flush memory: not on UI thread");
 227             return NS_ERROR_FAILURE;
 228         }
 229     }
 230
 231     PRInt32 lastVal = PR_AtomicSet(&sIsFlushing, 1);
 232     if (lastVal)
 233         return NS_OK;
 234
 235     // Run the flushers immediately if we can; otherwise, proxy to the
 236     // UI thread an run 'em asynchronously.
 237     if (aImmediate) {
 238         rv = RunFlushers(aReason);
 239     }
 240     else {
 241         sFlushEvent.mReason = aReason;
 242         rv = NS_DispatchToMainThread(&sFlushEvent, NS_DISPATCH_NORMAL);
 243     }
 244
 245     return rv;
 246 }
 247
 248 nsresult
 249 nsMemoryImpl::RunFlushers(const PRUnichar* aReason)
 250 {
 251     nsCOMPtr<nsIObserverService> os = do_GetService("@mozilla.org/observer-service;1");
 252     if (os) {
 253         os->NotifyObservers(this, "memory-pressure", aReason);
 254     }
 255
 256     sIsFlushing = 0;
 257     return NS_OK;
 258 }
 259
 260 // XXX need NS_IMPL_STATIC_ADDREF/RELEASE
 261 NS_IMETHODIMP_(nsrefcnt) nsMemoryImpl::FlushEvent::AddRef() { return 2; }
 262 NS_IMETHODIMP_(nsrefcnt) nsMemoryImpl::FlushEvent::Release() { return 1; }
 263 NS_IMPL_QUERY_INTERFACE1(nsMemoryImpl::FlushEvent, nsIRunnable)
 264
 265 NS_IMETHODIMP
 266 nsMemoryImpl::FlushEvent::Run()
 267 {
 268     sGlobalMemory.RunFlushers(mReason);
 269     return NS_OK;
 270 }
 271
 272 PRInt32
 273 nsMemoryImpl::sIsFlushing = 0;
 274
 275 nsMemoryImpl::FlushEvent
 276 nsMemoryImpl::sFlushEvent;
 277
 278 XPCOM_API(void*)
 279 NS_Alloc(PRSize size)
 280 {
 281     void* result = MALLOC1(size);
 282     if (! result) {
 283         // Request an asynchronous flush
 284         sGlobalMemory.FlushMemory(NS_LITERAL_STRING("alloc-failure").get(), PR_FALSE);
 285     }
 286     return result;
 287 }
 288
 289 XPCOM_API(void*)
 290 NS_Realloc(void* ptr, PRSize size)
 291 {
 292     void* result = REALLOC1(ptr, size);
 293     if (! result && size != 0) {
 294         // Request an asynchronous flush
 295         sGlobalMemory.FlushMemory(NS_LITERAL_STRING("alloc-failure").get(), PR_FALSE);
 296     }
 297     return result;
 298 }
 299
 300 XPCOM_API(void)
 301 NS_Free(void* ptr)
 302 {
 303     PR_Free(ptr);
 304 }
 305
 306 #ifdef NS_MEMORY_FLUSHER
 307
 308 NS_IMPL_QUERY_INTERFACE1(MemoryFlusher, nsITimerCallback)
 309
 310 NS_IMETHODIMP
 311 MemoryFlusher::Notify(nsITimer *timer)
 312 {
 313     PRBool isLowMemory;
 314     sGlobalMemory.IsLowMemory(&isLowMemory);
 315
 316 #ifdef NS_TEST_MEMORY_FLUSHER
 317     // Fire the flusher *every* time
 318     isLowMemory = PR_TRUE;
 319 #endif
 320
 321     if (isLowMemory)
 322         sGlobalMemory.FlushMemory(NS_LITERAL_STRING("low-memory").get(),
 323                                   PR_FALSE);
 324     return NS_OK;
 325 }
 326
 327 nsresult
 328 MemoryFlusher::Init()
 329 {
 330     nsCOMPtr<nsITimer> timer = do_CreateInstance(NS_TIMER_CONTRACTID);
 331     NS_ENSURE_STATE(timer);
 332
 333     // There is no need to keep a reference to the timer object because we
 334     // don't need to kill the timer.  It will be killed automatically when
 335     // XPCOM is shutdown.
 336
 337     return timer->InitWithCallback(this, kTimeout,
 338                                    nsITimer::TYPE_REPEATING_SLACK);
 339 }
 340
 341 #endif // NS_MEMORY_FLUSHER
 342
 343 nsresult
 344 NS_GetMemoryManager(nsIMemory* *result)
 345 {
 346     return sGlobalMemory.QueryInterface(NS_GET_IID(nsIMemory), (void**) result);
 347 }