动态 MMap 没有空间了。请增大APT::Cache-Limit 的大小

ubuntu 软件源的source list中如果选择了太多的软件源的话可能导致如下错误: “动态 MMap 没有空间了。

请增大APT::Cache-Limit 的大小” 解决方案: 编辑 sudo gedit /etc/apt/apt.conf(如果没有apt.conf这个文件就新建一个)

在里面增加或者修改以下参数,把后面的数字尽量的调大即可,如果调大后重复出现该问题,

继续增加数字即可 APT::Cache-Limit 99999999;

[2025.10.09-14.25.03:906][ 0]LogDeviceProfileManager: Going up to parent DeviceProfile [] [2025.10.09-14.25.03:906][ 0]LogConfig: Applying CVar settings from Section [Startup] File [../../../Engine/Config/ConsoleVariables.ini] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[r.DumpShaderDebugInfo:2]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[p.chaos.AllowCreatePhysxBodies:1]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[fx.SkipVectorVMBackendOptimizations:1]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[r.ForceDebugViewModes:1]] [2025.10.09-14.25.03:906][ 0]LogConfig: Applying CVar settings from Section [ConsoleVariables] File [Engine] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[HoverDrone.DroneSpeedScalar:0.5]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[fx.NiagaraGpuLowLatencyTranslucencyEnabled:1]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[P.Chaos.SyncKinematicOnGameThread:1]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[MovieRenderPipeline.WaveOutput.WriteDelay:3]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[p.ClothPhysics:0]] [2025.10.09-14.25.03:906][ 0]LogConfig: Set CVar [[g.TimeoutForBlockOnRenderFence:60000]] [2025.10.09-14.25.03:906][ 0]LogInit: Unix hardware info: [2025.10.09-14.25.03:906][ 0]LogInit: - we are the first instance of this executable [2025.10.09-14.25.03:906][ 0]LogInit: - this process' id (pid) is 168551, parent process' id (ppid) is 168543 [2025.10.09-14.25.03:906][ 0]LogInit: - we are not running under debugger [2025.10.09-14.25.03:907][ 0]LogInit: - machine network name is 'DESKTOP-2PJK7EV' [2025.10.09-14.25.03:907][ 0]LogInit: - user name is 'lxng' (lxng) [2025.10.09-14.25.03:907][ 0]LogInit: - we're logged in locally [2025.10.09-14.25.03:907][ 0]LogInit: - we're running with rendering [2025.10.09-14.25.03:907][ 0]LogInit: - CPU: GenuineIntel '12th Gen Intel(R) Core(TM) i9-12900K' (signature: 0x90672) [2025.10.09-14.25.03:907][ 0]LogInit: - Number of physical cores available for the process: 12 [2025.10.09-14.25.03:907][ 0]LogInit: - Number of logical cores available for the process: 24 [2025.10.09-14.25.03:907][ 0]LogInit: - GPU Brand Info: UnknownVendor [2025.10.09-14.25.03:907][ 0]LogInit: - Memory allocator used: binned2 [2025.10.09-14.25.03:907][ 0]LogInit: - This binary is optimized with LTO: no, PGO: no, instrumented for PGO data collection: no [2025.10.09-14.25.03:907][ 0]LogInit: - This is an internal build. [2025.10.09-14.25.03:907][ 0]LogCore: Benchmarking clocks: [2025.10.09-14.25.03:907][ 0]LogCore: - CLOCK_MONOTONIC (id=1) can sustain 50522507 (50523K, 51M) calls per second without zero deltas. [2025.10.09-14.25.03:907][ 0]LogCore: - CLOCK_MONOTONIC_RAW (id=4) can sustain 54124297 (54124K, 54M) calls per second without zero deltas. [2025.10.09-14.25.03:907][ 0]LogCore: - CLOCK_MONOTONIC_COARSE (id=6) can sustain 255663865 (255664K, 256M) calls per second with 99.999906% zero deltas. [2025.10.09-14.25.03:907][ 0]LogCore: Selected clock_id 4 (CLOCK_MONOTONIC_RAW) since it is the fastest support clock without zero deltas. [2025.10.09-14.25.03:907][ 0]LogInit: Unix-specific commandline switches: [2025.10.09-14.25.03:907][ 0]LogInit: -ansimalloc - use malloc()/free() from libc (useful for tools like valgrind and electric fence) [2025.10.09-14.25.03:907][ 0]LogInit: -jemalloc - use jemalloc for all memory allocation [2025.10.09-14.25.03:907][ 0]LogInit: -binnedmalloc - use binned malloc for all memory allocation [2025.10.09-14.25.03:907][ 0]LogInit: -filemapcachesize=NUMBER - set the size for case-sensitive file mapping cache [2025.10.09-14.25.03:907][ 0]LogInit: -useksm - uses kernel same-page mapping (KSM) for mapped memory (OFF) [2025.10.09-14.25.03:907][ 0]LogInit: -ksmmergeall - marks all mmap'd memory pages suitable for KSM (OFF) [2025.10.09-14.25.03:907][ 0]LogInit: -preloadmodulesymbols - Loads the main module symbols file into memory (OFF) [2025.10.09-14.25.03:907][ 0]LogInit: -sigdfl=SIGNAL - Allows a specific signal to be set to its default handler rather then ignoring the signal [2025.10.09-14.25.03:907][ 0]LogInit: -crashhandlerstacksize - Allows setting crash handler stack sizes (204800) [2025.10.09-14.25.03:907][ 0]LogInit: -noexclusivelockonwrite - disables marking files created by the engine as exclusive locked while the engine has them opened [2025.10.09-14.25.03:907][ 0]LogInit: -httpproxy=ADDRESS:PORT - redirects HTTP requests to a proxy (only supported if compiled with libcurl) [2025.10.09-14.25.03:907][ 0]LogInit: -reuseconn - allow libcurl to reuse HTTP connections (only matters if compiled with libcurl) [2025.10.09-14.25.03:907][ 0]LogInit: -virtmemkb=NUMBER - sets process virtual memory (address space) limit (overrides VirtualMemoryLimitInKB value from .ini) [2025.10.09-14.25.03:907][ 0]LogInit: -allowsyscallfilterfile=PATH_TO_FILE - sets up a system call filter allow list. any invalid syscall in this list *will* cause a crash [2025.10.09-14.25.03:907][ 0]LogInit: - Physical RAM available (not considering process quota): 32 GB (31986 MB, 32753812 KB, 33539903488 bytes) [2025.10.09-14.25.03:907][ 0]LogInit: - VirtualMemoryAllocator pools will grow at scale 1.4 [2025.10.09-14.25.03:907][ 0]LogInit: - MemoryRangeDecommit() will be a no-op (re-run with -vmapoolevict to change) [2025.10.09-14.25.03:907][ 0]LogInit: - PageSize 4096 [2025.10.09-14.25.03:907][ 0]LogInit: - BinnedPageSize 65536 [2025.10.09-14.25.03:907][ 0]LogCsvProfiler: Display: Metadata set : extradevelopmentmemorymb="0" [2025.10.09-14.25.03:911][ 0]LogInit: Physics initialised using underlying interface: Chaos [2025.10.09-14.25.03:911][ 0]LogInit: Using OS detected language (en-US-POSIX). [2025.10.09-14.25.03:911][ 0]LogInit: Using OS detected locale (en-US-POSIX). [2025.10.09-14.25.03:912][ 0]LogTextLocalizationManager: No specific localization for 'en-US-POSIX' exists, so 'en' will be used for the language. [2025.10.09-14.25.03:937][ 0]LogHAL: Warning: Game icon not found. [2025.10.09-14.25.04:238][ 0]LogSlate: New Slate User Created. Platform User Id 0, User Index 0, Is Virtual User: 0 [2025.10.09-14.25.04:238][ 0]LogSlate: Slate User Registered. User Index 0, Is Virtual User: 0
10-10
0x000000000b01626c CitySample!FVulkanCommandBufferManager::PrepareForNewActiveCommandBuffer()() 0x000000000b0e8901 CitySample!FVulkanViewport::Present(FVulkanCommandListContext*, FVulkanCmdBuffer*, FVulkanQueue*, FVulkanQueue*, bool)() 0x000000000b0a8080 CitySample!FVulkanCommandListContext::RHIEndDrawingViewport(FRHIViewport*, bool, bool)() 0x000000000b21bcb1 CitySample!FRHICommand<FRHICommandEndDrawingViewport, FRHICommandEndDrawingViewportString2071>::ExecuteAndDestruct(FRHICommandListBase&, FRHICommandListDebugContext&)() 0x000000000b1d6c5e CitySample!FRHICommandListBase::Execute(TRHIPipelineArray<IRHIComputeContext*>&, FRHICommandListBase::FPersistentState::FGPUStats*)() 0x000000000b233c1e CitySample!UE::Core::Private::Function::TFunctionRefCaller<FRHICommandListImmediate::ExecuteAndReset()::$_124, void ()>::Call(void*)() 0x00000000055913aa CitySample!TGraphTask<TFunctionGraphTaskImpl<void (), (ESubsequentsMode::Type)0> >::ExecuteTask(TArray<FBaseGraphTask*, TSizedDefaultAllocator<32> >&, ENamedThreads::Type, bool)() 0x0000000007ca4185 CitySample!FNamedTaskThread::ProcessTasksNamedThread(int, bool)() 0x0000000007ca27e0 CitySample!FNamedTaskThread::ProcessTasksUntilQuit(int)() 0x0000000007ca16d9 CitySample!FTaskGraphCompatibilityImplementation::ProcessThreadUntilRequestReturn(ENamedThreads::Type)() 0x000000000b31401c CitySample!FRHIThread::Run()() 0x0000000007db39a6 CitySample!FRunnableThreadPThread::Run()() 0x0000000007d381a8 CitySample!FRunnableThreadPThread::_ThreadProc(void*)() 0x00007965a3c94ac3 libc.so.6!UnknownFunction(0x94ac2) 0x00007965a3d268c0 libc.so.6!UnknownFunction(0x1268bf) [2025.10.11-12.13.49:200][ 29]LogExit: Executing StaticShutdownAfterError Malloc Size=131160 LargeMemoryPoolOffset=393352 Malloc Size=131160 LargeMemoryPoolOffset=524536 Malloc Size=792707 LargeMemoryPoolOffset=1317267 LogPakFile: Display: Found Pak file ../../../Engine/Programs/CrashReportClient/Content/Paks/CrashReportClient.pak attempting to mount. LogPakFile: Display: Mounting pak file ../../../Engine/Programs/CrashReportClient/Content/Paks/CrashReportClient.pak. LogPakFile: Display: Mounted Pak file '../../../Engine/Programs/CrashReportClient/Content/Paks/CrashReportClient.pak', mount point: '../../../Engine/' LogICUInternationalization: ICU TimeZone Detection - Raw Offset: +8:00, Platform Override: '' LogInit: ExecutableName: CrashReportClient LogInit: Build: ++UE5+Release-5.2-CL-26001984 LogInit: Engine Version: 5.2.1-26001984+++UE5+Release-5.2 LogInit: Compatible Engine Version: 5.2.0-25360045+++UE5+Release-5.2 LogInit: Net CL: 25360045 LogInit: OS: Ubuntu 22.04.5 LTS (6.8.0-85-generic), CPU: 12th Gen Intel(R) Core(TM) i9-12900K, GPU: NVIDIA GeForce RTX 4090 (NVIDIA UNIX x86_64 Kernel Module 580.65.06 Sun Jul 27 07:14:19 UTC 2025) LogInit: Compiled (64-bit): Jun 15 2023 05:00:12 LogInit: Architecture: x64 LogInit: Compiled with Clang: 15.0.1 (https://github.com/llvm/llvm-project b73d2c8c720a8c8e6e73b11be4e27afa6cb75bdf) LogInit: Build Configuration: Shipping LogInit: Branch Name: ++UE5+Release-5.2 LogInit: Command Line: -Abslog="/media/lxng/jixie/OpenFly-Platform/envs/ue/env_ue_bigcity/City_UE52/Saved/Logs/City_UE52-CRC.log" "/media/lxng/jixie/OpenFly-Platform/envs/ue/env_ue_bigcity/City_UE52/Saved/Crashes/crashinfo-City_UE52-pid-25976-C08B43F9B4B5419E88A5F06F0905ED43/" LogInit: Base Directory: /media/lxng/jixie/OpenFly-Platform/envs/ue/env_ue_bigcity/Engine/Binaries/Linux/ LogInit: Allocator: Mimalloc LogInit: Installed Engine Build: 1 LogInit: Presizing for max 100000 objects, including 0 objects not considered by GC, pre-allocating 0 bytes for permanent pool. LogInit: Object subsystem initialized [2025.10.11-12.13.49:251][ 0]LogConfig: Applying CVar settings from Section [ConsoleVariables] File [Engine] [2025.10.11-12.13.49:251][ 0]LogInit: Unix hardware info: [2025.10.11-12.13.49:251][ 0]LogInit: - we are the first instance of this executable [2025.10.11-12.13.49:251][ 0]LogInit: - this process' id (pid) is 26143, parent process' id (ppid) is 25976 [2025.10.11-12.13.49:251][ 0]LogInit: - we are not running under debugger [2025.10.11-12.13.49:251][ 0]LogInit: - machine network name is 'lxng-MS-7D31' [2025.10.11-12.13.49:251][ 0]LogInit: - user name is 'lxng' (lxng) [2025.10.11-12.13.49:251][ 0]LogInit: - we're logged in locally [2025.10.11-12.13.49:251][ 0]LogInit: - we're running with rendering [2025.10.11-12.13.49:251][ 0]LogInit: - CPU: GenuineIntel '12th Gen Intel(R) Core(TM) i9-12900K' (signature: 0x90672) [2025.10.11-12.13.49:251][ 0]LogInit: - Number of physical cores available for the process: 16 [2025.10.11-12.13.49:251][ 0]LogInit: - Number of logical cores available for the process: 24 [2025.10.11-12.13.49:251][ 0]LogInit: - GPU Brand Info: NVIDIA GeForce RTX 4090 (NVIDIA UNIX x86_64 Kernel Module 580.65.06 Sun Jul 27 07:14:19 UTC 2025) [2025.10.11-12.13.49:251][ 0]LogInit: - Memory allocator used: Mimalloc [2025.10.11-12.13.49:251][ 0]LogInit: - This binary is optimized with LTO: no, PGO: no, instrumented for PGO data collection: no [2025.10.11-12.13.49:251][ 0]LogInit: - This is an internal build. [2025.10.11-12.13.49:251][ 0]LogCore: Skipped benchmarking clocks because the engine is running in a standalone program mode - CLOCK_MONOTONIC will be used. [2025.10.11-12.13.49:251][ 0]LogInit: Unix-specific commandline switches: [2025.10.11-12.13.49:251][ 0]LogInit: -ansimalloc - use malloc()/free() from libc (useful for tools like valgrind and electric fence) [2025.10.11-12.13.49:251][ 0]LogInit: -jemalloc - use jemalloc for all memory allocation [2025.10.11-12.13.49:251][ 0]LogInit: -binnedmalloc - use binned malloc for all memory allocation [2025.10.11-12.13.49:251][ 0]LogInit: -filemapcachesize=NUMBER - set the size for case-sensitive file mapping cache [2025.10.11-12.13.49:251][ 0]LogInit: -useksm - uses kernel same-page mapping (KSM) for mapped memory (OFF) [2025.10.11-12.13.49:251][ 0]LogInit: -ksmmergeall - marks all mmap'd memory pages suitable for KSM (OFF) [2025.10.11-12.13.49:251][ 0]LogInit: -preloadmodulesymbols - Loads the main module symbols file into memory (OFF) [2025.10.11-12.13.49:251][ 0]LogInit: -sigdfl=SIGNAL - Allows a specific signal to be set to its default handler rather then ignoring the signal [2025.10.11-12.13.49:251][ 0]LogInit: -crashhandlerstacksize - Allows setting crash handler stack sizes (204800) [2025.10.11-12.13.49:251][ 0]LogInit: -noexclusivelockonwrite - disables marking files created by the engine as exclusive locked while the engine has them opened [2025.10.11-12.13.49:251][ 0]LogInit: -httpproxy=ADDRESS:PORT - redirects HTTP requests to a proxy (only supported if compiled with libcurl) [2025.10.11-12.13.49:251][ 0]LogInit: -reuseconn - allow libcurl to reuse HTTP connections (only matters if compiled with libcurl) [2025.10.11-12.13.49:251][ 0]LogInit: -virtmemkb=NUMBER - sets process virtual memory (address space) limit (overrides VirtualMemoryLimitInKB value from .ini) [2025.10.11-12.13.49:251][ 0]LogInit: -allowsyscallfilterfile=PATH_TO_FILE - sets up a system call filter allow list. any invalid syscall in this list *will* cause a crash [2025.10.11-12.13.49:251][ 0]LogInit: - Physical RAM available (not considering process quota): 63 GB (64086 MB, 65624688 KB, 67199680512 bytes) [2025.10.11-12.13.49:251][ 0]LogInit: - VirtualMemoryAllocator pools will grow at scale 1.4 [2025.10.11-12.13.49:251][ 0]LogInit: - MemoryRangeDecommit() will be a no-op (re-run with -vmapoolevict to change) [2025.10.11-12.13.49:251][ 0]LogInit: - PageSize 4096 [2025.10.11-12.13.49:251][ 0]LogInit: - BinnedPageSize 65536 [2025.10.11-12.13.49:252][ 0]LogUObjectArray: 427 objects as part of root set at end of initial load. [2025.10.11-12.13.49:252][ 0]LogUObjectAllocator: 89672 out of 0 bytes used by permanent object pool. [2025.10.11-12.13.49:252][ 0]LogUObjectArray: CloseDisregardForGC: 0/0 objects in disregard for GC pool [2025.10.11-12.13.49:252][ 0]LogPaths: Warning: No paths for game localization data were specifed in the game configuration. [2025.10.11-12.13.49:252][ 0]LogInit: Using OS detected language (zh-CN). [2025.10.11-12.13.49:252][ 0]LogInit: Using OS detected locale (zh-CN). [2025.10.11-12.13.49:252][ 0]LogInit: Warning: No paths for engine localization data were specifed in the engine configuration. [2025.10.11-12.13.49:252][ 0]LogTextLocalizationManager: No localization for 'zh-CN' exists, so 'en' will be used for the language. [2025.10.11-12.13.49:252][ 0]LogTextLocalizationManager: No localization for 'zh-CN' exists, so 'en' will be used for the locale. [2025.10.11-12.13.49:252][ 0]LogInit: Using OS detected language (zh-CN). [2025.10.11-12.13.49:252][ 0]LogInit: Using OS detected locale (zh-CN). [2025.10.11-12.13.49:252][ 0]LogTextLocalizationManager: No localization for 'zh-CN' exists, so 'en' will be used for the language. [2025.10.11-12.13.49:252][ 0]LogTextLocalizationManager: No localization for 'zh-CN' exists, so 'en' will be used for the locale. [2025.10.11-12.13.49:253][ 0]LogPackageLocalizationCache: Processed 2 localized package path(s) for 1 prioritized culture(s) in 0.000164 seconds [2025.10.11-12.13.49:253][ 0]CrashReportCoreLog: CrashReportClientVersion=1.0 [2025.10.11-12.13.49:253][ 0]CrashReportCoreLog: CrashReportReceiver disabled [2025.10.11-12.13.49:253][ 0]CrashReportCoreLog: DataRouterUrl: https://datarouter.ol.epicgames.com/datarouter/api/v1/public/data [2025.10.11-12.13.49:257][ 0]LogInit: Using libcurl 7.83.1 [2025.10.11-12.13.49:257][ 0]LogInit: - built for Linux [2025.10.11-12.13.49:257][ 0]LogInit: - supports SSL with OpenSSL/1.1.1n [2025.10.11-12.13.49:257][ 0]LogInit: - supports HTTP deflate (compression) using libz 1.2.12 [2025.10.11-12.13.49:257][ 0]LogInit: - other features: [2025.10.11-12.13.49:257][ 0]LogInit: CURL_VERSION_SSL [2025.10.11-12.13.49:257][ 0]LogInit: CURL_VERSION_LIBZ [2025.10.11-12.13.49:257][ 0]LogInit: CURL_VERSION_IPV6 [2025.10.11-12.13.49:257][ 0]LogInit: CURL_VERSION_ASYNCHDNS [2025.10.11-12.13.49:257][ 0]LogInit: CURL_VERSION_LARGEFILE [2025.10.11-12.13.49:257][ 0]LogInit: CurlRequestOptions (configurable via config and command line): [2025.10.11-12.13.49:257][ 0]LogInit: - bVerifyPeer = false - Libcurl will NOT verify peer certificate [2025.10.11-12.13.49:257][ 0]LogInit: - bUseHttpProxy = false - Libcurl will NOT use HTTP proxy [2025.10.11-12.13.49:257][ 0]LogInit: - bDontReuseConnections = false - Libcurl will reuse connections [2025.10.11-12.13.49:257][ 0]LogInit: - MaxHostConnections = 16 - Libcurl will limit the number of connections to a host [2025.10.11-12.13.49:257][ 0]LogInit: - LocalHostAddr = Default [2025.10.11-12.13.49:257][ 0]LogInit: - BufferSize = 65536 [2025.10.11-12.13.49:257][ 0]LogAnalytics: Display: [CrashReporter.Release] APIServer = https://datarouter.ol.epicgames.com/. AppVersion = ++UE5+Release-5.2-CL-26001984 [2025.10.11-12.13.49:257][ 0]LogInit: Initializing SDL. [2025.10.11-12.13.49:271][ 0]LogInit: Initialized SDL 2.24.0 revision: (compiled against 2.24.0) [2025.10.11-12.13.49:271][ 0]LogInit: Using SDL video driver 'x11' [2025.10.11-12.13.49:273][ 0]LogSlate: New Slate User Created. Platform User Id 0, User Index 0, Is Virtual User: 0 [2025.10.11-12.13.49:273][ 0]LogSlate: Slate User Registered. User Index 0, Is Virtual User: 0 [2025.10.11-12.13.49:273][ 0]LogSlate: Using FreeType 2.10.0 [2025.10.11-12.13.49:274][ 0]LogSlate: SlateFontServices - WITH_FREETYPE: 1, WITH_HARFBUZZ: 1 [2025.10.11-12.13.49:274][ 0]LogInit: Using SDL_WINDOW_OPENGL [2025.10.11-12.13.49:294][ 0]LogInit: FSlateOpenGLContext::Initialize - creating OpenGL 2.1 context [2025.10.11-12.13.49:316][ 0]CrashReportCoreLog: Initial state = Unknown UploadState value [2025.10.11-12.13.49:316][ 0]CrashReportCoreLog: Initial state = Unknown UploadState value [2025.10.11-12.13.49:317][ 0]LogLinux: Could not get DPI information for monitor #0, assuming 1.0f [2025.10.11-12.13.49:317][ 0]LogLinux: Could not get DPI information for monitor #0, assuming 1.0f [2025.10.11-12.13.49:318][ 0]LogInit: FSlateOpenGLContext::Initialize - creating OpenGL 2.1 context [2025.10.11-12.13.49:320][ 0]LogSlate: Took 0.000510 seconds to synchronously load lazily loaded font '../../../Engine/Content/Slate/Fonts/Roboto-Regular.ttf' (155K) [2025.10.11-12.13.49:321][ 0]LogSlate: Took 0.000544 seconds to synchronously load lazily loaded font '../../../Engine/Content/Slate/Fonts/Roboto-Bold.ttf' (160K) [2025.10.11-12.13.49:322][ 0]LogSlate: Took 0.000511 seconds to synchronously load lazily loaded font '../../../Engine/Content/Slate/Fonts/Roboto-Italic.ttf' (157K)
10-12
Android 系统在内存管理和虚拟机运行时采用了一系列机制,其中 `anon_shmem` 和 `/dev/ashmem/dalvik-jit-code-cache` 是与 Dalvik 虚拟机(以及 ART 虚拟机的兼容模式)紧密相关的内存使用部分,尤其是在涉及 JIT(Just-In-Time)编译和代码缓存的场景中。 ### `anon_shmem` 的作用与使用 `anon_shmem` 是一种基于 `tmpfs` 文件系统的共享内存机制,通常用于匿名共享内存分配。在 Android 中,它被广泛用于进程间通信(IPC)和内存映射(mmap)操作。例如,当应用使用 `ashmem`(Android Shared Memory)接口创建共享内存区域时,系统会在 `/dev/ashmem` 下创建对应的条目,并将其映射为 `anon_shmem` 类型的内存。 在 `/proc/meminfo` 中,`Shmem` 字段反映了当前系统中被 `anon_shmem` 使用的内存总量。这部分内存可以被回收,属于可缓存类型,因此在内存紧张时会被系统回收[^1]。 ### `/dev/ashmem/dalvik-jit-code-cache` 的作用 在 Dalvik 虚拟机中,JIT 编译器会动态将字节码编译为本地机器码以提升执行效率。为了缓存这些编译后的机器码,Dalvik 使用了 `/dev/ashmem/dalvik-jit-code-cache` 这个共享内存区域。该缓存机制允许虚拟机在运行时重复使用已编译的代码,从而减少重复编译的开销并提升性能。 然而,该区域的内存使用也可能引发问题。例如,在某些版本的 Android 系统中,JIT 缓存可能导致内存泄漏或虚拟机崩溃,表现为崩溃日志中出现类似以下堆栈信息: ``` backtrace: #00 pc 00033cf8 /dev/ashmem/dalvik-jit-code-cache (deleted) #01 pc 00033ea1 /dev/ashmem/dalvik-jit-code-cache (deleted) ``` 这类问题通常与 JIT 编译缓存的管理不当或共享内存区域的异常释放有关。解决方案包括优化 JIT 缓存策略、限制缓存大小或在特定场景下禁用 JIT 编译功能[^3]。 ### Android 内存管理中的影响 在 Android 系统的内存统计中,`dalvik-jit-code-cache` 和 `anon_shmem` 的使用会体现在多个维度中。例如: - `/proc/meminfo` 中的 `Shmem` 字段会包含 `dalvik-jit-code-cache` 的内存占用。 - 在内存紧张时,这些共享内存区域可能被系统回收。 - 在某些场景下,如低内存杀进程(LMK)触发时,系统会优先回收非关键的共享内存区域以释放资源。 此外,在 Android 的内存分析工具(如 `dumpsys meminfo`)中,这些区域也会被单独列出,帮助开发者识别内存使用情况并优化应用行为。 ### 示例:查看 dalvik-jit-code-cache 使用情况 可以通过如下命令查看当前系统中 `/dev/ashmem/dalvik-jit-code-cache` 的使用情况: ```bash adb shell cat /proc/<pid>/maps | grep dalvik-jit-code-cache ``` 其中 `<pid>` 是目标应用的进程 ID。输出结果将显示该缓存区域的内存映射情况,包括起始地址、权限、偏移量等信息。 ### 总结 - `anon_shmem` 是 Android 中用于共享内存管理的重要机制,广泛用于 IPC 和缓存。 - `/dev/ashmem/dalvik-jit-code-cache` 是 Dalvik 虚拟机用于 JIT 编译缓存的共享内存区域,提升运行时性能但也可能引发内存或崩溃问题。 - 在内存管理中,这些区域的使用会影响系统整体内存统计和回收策略。
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