我有一个视频检索系统，在检索过程中会占用大量内存。我知道tbb可伸缩分配器会将释放的内存释放到内存池，而不会将其返回给操作系统。这是否意味着池将始终在其池中具有先前分配的内存，并且当其他线程需要内存时，它可能会导致内存耗尽？
我正在使用2台24核，47G内存的机器。我的程序有24个线程，每个线程处理一个检索任务，并使用tbb可伸缩分配器进行内存分配，但它仍然会得到错误的alloc异常。我还使用valgrind来检测内存泄漏并找到下面的报告，似乎它只有“仍然可达”的问题，这是由tbb可伸缩分配器引起的，没有其他内存泄漏。有谁能告诉我如何解决这个问题？
==1224== HEAP SUMMARY:
==1224== in use at exit: 147,456 bytes in 9 blocks
==1224== total heap usage: 10 allocs, 1 frees, 148,480 bytes allocated
==1224==
==1224== Thread 1:
==1224== 16,384 bytes in 1 blocks are still reachable in loss record 1 of 4
==1224== at 0x4A0610C: malloc (vg_replace_malloc.c:195)
==1224== by 0x4E285C6: rml::internal::getRawMemory(unsigned long, bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AB2B: rml::internal::BackRefMaster::findFreeBlock() (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AE49: rml::internal::BackRefIdx::newBackRef(bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E26C49: rml::internal::MemoryPool::getEmptyBlock(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27676: rml::internal::internalPoolMalloc(rml::MemoryPool*, unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27825: scalable_malloc (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4C21278: operator new(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc_proxy.so.2)
==1224== by 0x458922: __gnu_cxx::new_allocator<__gnu_cxx::_Hashtable_node<std::pair<unsigned int const, s_Keypoint*> > >::allocate(unsigned long, void const*) (new_allocator.h:88)
==1224== by 0x458947: __gnu_cxx::hashtable<std::pair<unsigned int const, s_Keypoint*>, unsigned int, __gnu_cxx::hash<unsigned int>, std::_Select1st<std::pair<unsigned int const, s_Keypoint*> >, std::equal_to<unsigned int>, std::allocator<s_Keypoint*> >::_M_get_node() (hashtable.h:297)
==1224== by 0x458963: __gnu_cxx::hashtable<std::pair<unsigned int const, s_Keypoint*>, unsigned int, __gnu_cxx::hash<unsigned int>, std::_Select1st<std::pair<unsigned int const, s_Keypoint*> >, std::equal_to<unsigned int>, std::allocator<s_Keypoint*> >::_M_new_node(std::pair<unsigned int const, s_Keypoint*> const&) (hashtable.h:605)
==1224== by 0x458ABC: __gnu_cxx::hashtable<std::pair<unsigned int const, s_Keypoint*>, unsigned int, __gnu_cxx::hash<unsigned int>, std::_Select1st<std::pair<unsigned int const, s_Keypoint*> >, std::equal_to<unsigned int>, std::allocator<s_Keypoint*> >::insert_equal_noresize(std::pair<unsigned int const, s_Keypoint*> const&) (hashtable.h:783)
==1224==
==1224== 16,384 bytes in 1 blocks are still reachable in loss record 2 of 4
==1224== at 0x4A0610C: malloc (vg_replace_malloc.c:195)
==1224== by 0x4E285C6: rml::internal::getRawMemory(unsigned long, bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AB2B: rml::internal::BackRefMaster::findFreeBlock() (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AE49: rml::internal::BackRefIdx::newBackRef(bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2A690: rml::internal::mallocLargeObject(rml::internal::ExtMemoryPool*, unsigned long, unsigned long, bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27825: scalable_malloc (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4C21278: operator new(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc_proxy.so.2)
==1224== by 0x4553AC: __gnu_cxx::new_allocator<s_Keypoint*>::allocate(unsigned long, void const*) (new_allocator.h:88)
==1224== by 0x4553D4: std::_Vector_base<s_Keypoint*, std::allocator<s_Keypoint*> >::_M_allocate(unsigned long) (stl_vector.h:127)
==1224== by 0x455C33: std::vector<s_Keypoint*, std::allocator<s_Keypoint*> >::_M_insert_aux(__gnu_cxx::__normal_iterator<s_Keypoint**, std::vector<s_Keypoint*, std::allocator<s_Keypoint*> > >, s_Keypoint* const&) (vector.tcc:275)
==1224== by 0x455E87: std::vector<s_Keypoint*, std::allocator<s_Keypoint*> >::push_back(s_Keypoint* const&) (stl_vector.h:610)
==1224== by 0x45711C: DirectHash::getNeighbors1(std::vector<s_Keypoint*, std::allocator<s_Keypoint*> >&, unsigned int) (directhash.cpp:157)
==1224==
==1224== 49,152 bytes in 3 blocks are still reachable in loss record 3 of 4
==1224== at 0x4A0610C: malloc (vg_replace_malloc.c:195)
==1224== by 0x4E285C6: rml::internal::getRawMemory(unsigned long, bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AB2B: rml::internal::BackRefMaster::findFreeBlock() (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AE49: rml::internal::BackRefIdx::newBackRef(bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E26C49: rml::internal::MemoryPool::getEmptyBlock(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27676: rml::internal::internalPoolMalloc(rml::MemoryPool*, unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27825: scalable_malloc (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4C21278: operator new(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc_proxy.so.2)
==1224== by 0x458922: __gnu_cxx::new_allocator<__gnu_cxx::_Hashtable_node<std::pair<unsigned int const, s_Keypoint*> > >::allocate(unsigned long, void const*) (new_allocator.h:88)
==1224== by 0x458947: __gnu_cxx::hashtable<std::pair<unsigned int const, s_Keypoint*>, unsigned int, __gnu_cxx::hash<unsigned int>, std::_Select1st<std::pair<unsigned int const, s_Keypoint*> >, std::equal_to<unsigned int>, std::allocator<s_Keypoint*> >::_M_get_node() (hashtable.h:297)
==1224== by 0x458963: __gnu_cxx::hashtable<std::pair<unsigned int const, s_Keypoint*>, unsigned int, __gnu_cxx::hash<unsigned int>, std::_Select1st<std::pair<unsigned int const, s_Keypoint*> >, std::equal_to<unsigned int>, std::allocator<s_Keypoint*> >::_M_new_node(std::pair<unsigned int const, s_Keypoint*> const&) (hashtable.h:605)
==1224== by 0x458A42: __gnu_cxx::hashtable<std::pair<unsigned int const, s_Keypoint*>, unsigned int, __gnu_cxx::hash<unsigned int>, std::_Select1st<std::pair<unsigned int const, s_Keypoint*> >, std::equal_to<unsigned int>, std::allocator<s_Keypoint*> >::insert_equal_noresize(std::pair<unsigned int const, s_Keypoint*> const&) (hashtable.h:776)
==1224==
==1224== 65,536 bytes in 4 blocks are still reachable in loss record 4 of 4
==1224== at 0x4A0610C: malloc (vg_replace_malloc.c:195)
==1224== by 0x4E285C6: rml::internal::getRawMemory(unsigned long, bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AB2B: rml::internal::BackRefMaster::findFreeBlock() (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E2AE49: rml::internal::BackRefIdx::newBackRef(bool) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E26C49: rml::internal::MemoryPool::getEmptyBlock(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27676: rml::internal::internalPoolMalloc(rml::MemoryPool*, unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4E27825: scalable_malloc (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc.so.2)
==1224== by 0x4C21278: operator new(unsigned long) (in /home/is_admin/tbb40_233oss/build/linux_intel64_gcc_cc4.1.2_libc2.5_kernel2.6.18_release/libtbbmalloc_proxy.so.2)
==1224== by 0x453A97: readKeysFromFile(char const*, int) (keypoint.cpp:329)
==1224== by 0x45D929: KeypointDB::Add(char const*) (keypointdb.cpp:201)
==1224== by 0x44A264: MRSystem::MRServer::AddFingerPrint(std::string) (mrserver.cpp:68)
==1224== by 0x445D68: MRSystem::Slave::ConstructHashTable() (Slave.cpp:242)
==1224==
==1224== LEAK SUMMARY:
==1224== definitely lost: 0 bytes in 0 blocks
==1224== indirectly lost: 0 bytes in 0 blocks
==1224== possibly lost: 0 bytes in 0 blocks
==1224== still reachable: 147,456 bytes in 9 blocks
==1224== suppressed: 0 bytes in 0 blocks
==1224==
==1224== For counts of detected and suppressed errors, rerun with: -v
==1224== Use --track-origins=yes to see where uninitialised values come from
==1224== ERROR SUMMARY: 3 errors from 1 contexts (suppressed: 4 from 4)
答案 0 :(得分：3)
在4.0之前的版本中，tbbmalloc用于分配“小”（＆lt; 8K）对象的内存块仅可供从OS请求它的线程重用。因此问题中描述的情况 - “一个线程将在其池中始终具有那些先前分配的内存，当其他线程需要内存时，它可能会导致内存耗尽” - 这是可能的。
自v4.0（2011年发布）以来，TBB内存分配器可能会将所有内存返回给操作系统。所以所描述的问题不再相关。如果某人仍然使用旧版本的tbbmalloc并遇到所描述的问题，解决方案是升级分配器。