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Bug 1230162 - allocate less, when we can. r=luke

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--HG--
extra : rebase_source : 41044134714073a611a70ccaf065a61b25553db1
extra : amend_source : a4fac35ff4f5b36636ba9c9d596d29276483d565
This commit is contained in:
Lars T Hansen 2015-12-03 16:52:31 +01:00
parent e23061aecc
commit 78aa2c6f8d
1 changed files with 44 additions and 30 deletions
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74
js/src/vm/SharedArrayObject.cpp
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@ -101,34 +101,41 @@ SharedArrayRawBuffer::New(JSContext* cx, uint32_t length)
if (allocSize <= length)
return nullptr;
#if defined(ASMJS_MAY_USE_SIGNAL_HANDLERS_FOR_OOB)
// Test >= to guard against the case where multiple extant runtimes
// race to allocate.
if (++numLive >= maxLive) {
JSRuntime* rt = cx->runtime();
if (rt->largeAllocationFailureCallback)
rt->largeAllocationFailureCallback(rt->largeAllocationFailureCallbackData);
if (numLive >= maxLive) {
void* p = nullptr;
if (!IsValidAsmJSHeapLength(length)) {
p = MapMemory(allocSize, true);
if (!p)
return nullptr;
} else {
// Test >= to guard against the case where multiple extant runtimes
// race to allocate.
if (++numLive >= maxLive) {
JSRuntime* rt = cx->runtime();
if (rt->largeAllocationFailureCallback)
rt->largeAllocationFailureCallback(rt->largeAllocationFailureCallbackData);
if (numLive >= maxLive) {
numLive--;
return nullptr;
}
}
// Get the entire reserved region (with all pages inaccessible)
p = MapMemory(SharedArrayMappedSize, false);
if (!p) {
numLive--;
return nullptr;
}
}
// Get the entire reserved region (with all pages inaccessible)
void* p = MapMemory(SharedArrayMappedSize, false);
if (!p) {
numLive--;
return nullptr;
}
if (!MarkValidRegion(p, allocSize)) {
UnmapMemory(p, SharedArrayMappedSize);
numLive--;
return nullptr;
}
if (!MarkValidRegion(p, allocSize)) {
UnmapMemory(p, SharedArrayMappedSize);
numLive--;
return nullptr;
}
# if defined(MOZ_VALGRIND) && defined(VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE)
// Tell Valgrind/Memcheck to not report accesses in the inaccessible region.
VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE((unsigned char*)p + allocSize,
SharedArrayMappedSize - allocSize);
// Tell Valgrind/Memcheck to not report accesses in the inaccessible region.
VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE((unsigned char*)p + allocSize,
SharedArrayMappedSize - allocSize);
# endif
}
#else
void* p = MapMemory(allocSize, true);
if (!p)
@ -136,7 +143,9 @@ SharedArrayRawBuffer::New(JSContext* cx, uint32_t length)
#endif
uint8_t* buffer = reinterpret_cast<uint8_t*>(p) + AsmJSPageSize;
uint8_t* base = buffer - sizeof(SharedArrayRawBuffer);
return new (base) SharedArrayRawBuffer(buffer, length);
SharedArrayRawBuffer* rawbuf = new (base) SharedArrayRawBuffer(buffer, length);
MOZ_ASSERT(rawbuf->length == length); // Deallocation needs this
return rawbuf;
}
void
@ -159,18 +168,23 @@ SharedArrayRawBuffer::dropReference()
MOZ_ASSERT(p.asValue() % AsmJSPageSize == 0);
uint8_t* address = p.unwrap(/*safe - only reference*/);
uint32_t allocSize = (this->length + 2*AsmJSPageSize - 1) & ~(AsmJSPageSize - 1);
#if defined(ASMJS_MAY_USE_SIGNAL_HANDLERS_FOR_OOB)
numLive--;
UnmapMemory(address, SharedArrayMappedSize);
if (!IsValidAsmJSHeapLength(allocSize)) {
UnmapMemory(address, allocSize);
} else {
numLive--;
UnmapMemory(address, SharedArrayMappedSize);
# if defined(MOZ_VALGRIND) \
&& defined(VALGRIND_ENABLE_ADDR_ERROR_REPORTING_IN_RANGE)
// Tell Valgrind/Memcheck to recommence reporting accesses in the
// previously-inaccessible region.
VALGRIND_ENABLE_ADDR_ERROR_REPORTING_IN_RANGE(address,
SharedArrayMappedSize);
// Tell Valgrind/Memcheck to recommence reporting accesses in the
// previously-inaccessible region.
VALGRIND_ENABLE_ADDR_ERROR_REPORTING_IN_RANGE(address,
SharedArrayMappedSize);
# endif
}
#else
UnmapMemory(address, this->length + AsmJSPageSize);
UnmapMemory(address, allocSize);
#endif
}
}