[zz]What does anon mean for pmap?

最新推荐文章于 2024-06-29 12:18:48 发布

最新推荐文章于 2024-06-29 12:18:48 发布 · 380 阅读

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本文解释了Anon Blocks的含义及其用途，特别是在malloc或mmap分配的大块内存中。此外，文章还探讨了Anon Blocks与Java堆之间的关系，并讨论了在不同场景下Anon Blocks的应用，例如线程栈。最后，本文提供了如何识别潜在内存泄漏问题的线索。

[url]http://stackoverflow.com/questions/1477885/trying-to-locate-a-leak-what-does-anon-mean-for-pmap[/url]

Anon blocks are "large" blocks allocated via malloc or mmap -- see the manpages. As such, they have nothing to do with the Java heap (other than the fact that the entire heap should be stored in just such a block).

In my experience, thread stacks also use anon blocks. If you see a lot of anon blocks that all have the same size, and that size is 512k to 4Mb (the example below is repeated over a dozen times for a Tomcat process that I have running), that's the likely cause. Depending on the program, you may have up to a few dozen of these; if you're seeing thousands, it means you have a problem with threading.

b089f000 504K rwx-- [ anon ]
b091d000 12K ----- [ anon ]
b0920000 504K rwx-- [ anon ]
b099e000 12K ----- [ anon ]
b09a1000 504K rwx-- [ anon ]
b0a1f000 12K ----- [ anon ]