Original address: http://www.javatang.comA period of time on-line after the system upgrade, there is a serious high CPU problem, so began a series of optimization processing, now the process into a series of articles.Basic conceptsWhen analyzing a Java memory leak, you need a dump file that records the memory footprint
Package com.ckw.mianshi;/** * Test memory leaks * Several events in Java that cause memory leaks: * A reference to an object that is held in a container such as 1.hashmap,verctor, although the object is already set to NULL, a memory leak * 2 will still occur. The use of the
.... ..... ....... ..............................Snapshot resolved.Started HTTP server on port 7000Server is ready.
Dump file created Thu Mar 16:45:06 CST 2015
Snapshot Read, resolving ...
Resolving 264282 objects ...
Chasing references, expect, dots ..... ..... ..... ....... .........................
Eliminating duplicate references .... ..... ....... ..............................
Snapshot resolved.
Started HTTP server on port 7000
Server is ready.
3. The address bar input ip
, the next is to open the Code project for White-box transformation, the corresponding code optimization (not within the scope of this article.) Some of the PID inconsistencies in the diagram are not tangled, some of the system restarted again.For more content please visit the starting blog http://jenwang.meFurther communication:-Email:[email protected]-For some topics of this blog interested in, hope to further exchange, please add QQ Group: 2825967-more technical exchange sharing in the Circle
Override hashcode member variable changed, object in set cannot find1. Use the Hashcode function of the object to determine the memory location initially, and if there is no storage object at that location, store the object in this2, if the hash function directly calculated memory address space already has an object exists, will use the object's equals to determine whether the object is equal, if not equal
Jstat-gcutil PID 10000
Lsof-p PID
Lsof-p PID | Wc-l
LS-AL/PROC/PID/FD #直接打印出当前此process all open files
jmap-histo:live pid > Info.log
Jmap-dump:live,file=mydumpfile PID
Jhat Mydumpfile
http://ip:7000 page directly to the bottom, you can see the number of instances cited ranking, where memory leaks.
Lsof-p 26674 ls-al/proc/pid/fdThere are large quantities of open anon_inode:[eventpoll] and pipe, if more than 100 eventpoll,Typically, too many handlert
Memory leaks are always a headache, and the following three commands I personally find quite useful.
1. Jstack (unique under Linux)
You can observe the current status of all threads in the JVM and the current state of the thread
Jstack 2083
The output reads as follows:
2, Jmap (Linux is unique, but also a very common command)
Observe the footprint of the running JVM's physical memory.
The parameters are
[Android] [Memory Leak] Inputmethodmanager memory leak phenomenon and its solutionphenomena : on the k_touch_v9 model of a particular model , an interface appears Inputmethodmanager hold a Activity, causes the Activity cannot be recycled . if the Activity be opened again , then the old ones will be released. , but the
Memory Overflow (OOM): a situation in which running memory is larger than available memory. For example, the application of an integer space, the result is stored only a long to store the data memory leak (memory
1. What is a memory leak?Memory leak refers to the dynamic application of memory in the program after use, no release, resulting in this part of the memory is not reclaimed by the system, over time, may cause the program
Common memory leak lookup methods see: http://hukai.me/android-performance-patterns/This article is an example of Google's release of the Android performance optimization paradigm, which provides a good demonstration of rendering, memory GC, and power consumption.Here I summarize the following, common memory leaks in A
What is the memory leak in the program?
We have written many programs with the keyword Free (). For example, I am in this post about some of the important operations of the list (Important operations on a Linked list) to delete the entire list of this function, the code snippet is as follows:struct node * deletelist (struct node * head) { struct node * temp; while (Head! = NULL) { =
interface, but more than 1.41M!!! This is key.Next, let's find out where the leak happened. Click Dump Java Heap to generate the snapshot file Tool.test.memory.memoryleak_2016.11.13_21.38.hprof,android Studio automatically pops up hprof viewer to analyze it.Snapshot file analysis. pngNow introduce the usage of the Hprof Viewer
HPROF Viewer View modeThe upper-left corner of the two red boxes, is an
when we use C + + to do the underlying driver, often encounter memory shortage warning, the reason is often because of memory overflow, leakage or cross-border reasons. So what's the connection between them? memory overflow (out of Memories)means that the program does not have enough memory space for it to use when it
Original: https://vld.codeplex.com/Visual Leak Detector is a memory leak detection tool dedicated to Visual C + +, which is free, open source, and highly robust.VLD is easy to use:1. After installing VLD, just tell Visual C + + where to find its header files and libraries. (: https://vld.codeplex.com)2. You can then use VLD by adding the following line of code to
subclass's destructor?Because the premise of polymorphism is virtual function.Under normal circumstances, the destructor of a class should be written as a virtual function, which, if forgotten, could cause a memory leak.(2) A space for an array is applied, but only the space of the first element is releasedclassnewclass[5];delete pA;Not all of these situations can lead to
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I recently heard about the memory leakage seminar of memory leak, and I felt a bit rewarding. So I kept a record and shared it with my friends.
1. What is memory leak.Memory Leak
. the only exception is stdafx. H (or any other precompiled header ). a precompiled header, such as stdafx. h, must always be the first header encoded in a source file, so VLD. h must be encoded ded after any precompiled headers.2. if your program contains one or more DLLs that you wowould also like to check for memory leaks, then also include VLD. h in at least one source file from each DLL to be removed ded in l
A memory leak is a common and troubling problem for a C + + programmer. Many techniques have been developed to deal with this problem, such as Smart pointer,garbage collection. Smart pointer technology is more mature, the STL already contains the class to support the smart pointer, but it does not seem to be widely used, and it does not solve all the problems; garbage collection technology has matured in
Memory overflow out of memory, which means that the program does not have enough memory space for it to use when applying for memory, and it appears out of the memory; For example, an integer is applied, but the number that has long to save is the
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