folly::fibers::GuardPageAllocator Class Reference

#include <GuardPageAllocator.h>

Public Member Functions
	GuardPageAllocator (bool useGuardPages)
	~GuardPageAllocator ()
unsigned char *	allocate (size_t size)
void	deallocate (unsigned char *limit, size_t size)

Private Attributes
std::unique_ptr< StackCacheEntry >	stackCache_
std::allocator< unsigned char >	fallbackAllocator_
bool	useGuardPages_ {true}

Detailed Description

Stack allocator that protects an extra memory page after the end of the stack. Will only add extra memory pages up to a certain number of allocations to avoid creating too many memory maps for the process.

Definition at line 31 of file GuardPageAllocator.h.

Constructor & Destructor Documentation

folly::fibers::GuardPageAllocator::GuardPageAllocator ( bool  useGuardPages )

explicit

Parameters

useGuardPages

if true, protect limited amount of stacks with guard pages, otherwise acts as std::allocator.

Definition at line 293 of file GuardPageAllocator.cpp.

References ~GuardPageAllocator().

    : useGuardPages_(useGuardPages) {
#ifndef _WIN32
  installSignalHandler();
#endif
}

folly::fibers::GuardPageAllocator::~GuardPageAllocator ( )

default

Referenced by GuardPageAllocator().

Member Function Documentation

unsigned char * folly::fibers::GuardPageAllocator::allocate

(

size_t

size

)

Returns

pointer to the bottom of the allocated stack of `size' bytes.

Definition at line 302 of file GuardPageAllocator.cpp.

References fallbackAllocator_, folly::fibers::CacheManager::getStackCache(), folly::fibers::CacheManager::instance(), stackCache_, and useGuardPages_.

                                                       {
  if (useGuardPages_ && !stackCache_) {
    stackCache_ = CacheManager::instance().getStackCache(size);
  }

  if (stackCache_) {
    auto p = stackCache_->cache().borrow(size);
    if (p != nullptr) {
      return p;
    }
  }
  return fallbackAllocator_.allocate(size);
}

void folly::fibers::GuardPageAllocator::deallocate	(	unsigned char *	limit,
		size_t	size
	)

Deallocates the previous result of an `allocate(size)' call.

Definition at line 316 of file GuardPageAllocator.cpp.

References fallbackAllocator_, and stackCache_.

Referenced by folly::fibers::Fiber::~Fiber().

                                                                     {
  if (!(stackCache_ && stackCache_->cache().giveBack(limit, size))) {
    fallbackAllocator_.deallocate(limit, size);
  }
}

Member Data Documentation

std::allocator<unsigned char> folly::fibers::GuardPageAllocator::fallbackAllocator_

private

Definition at line 52 of file GuardPageAllocator.h.

Referenced by allocate(), and deallocate().

std::unique_ptr<StackCacheEntry> folly::fibers::GuardPageAllocator::stackCache_

private

Definition at line 51 of file GuardPageAllocator.h.

Referenced by allocate(), and deallocate().

bool folly::fibers::GuardPageAllocator::useGuardPages_ {true}

private

Definition at line 53 of file GuardPageAllocator.h.

Referenced by allocate().

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The documentation for this class was generated from the following files:

• proxygen/folly/folly/fibers/GuardPageAllocator.h
• proxygen/folly/folly/fibers/GuardPageAllocator.cpp