Code review request: CR 6995781 Native Memory Tracking Phase 1

[Zhengyu Gu]

Sorry, the public CRs are:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6995781 
<http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7170449>
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7151532 
<http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7170449>

Thanks,

-Zhengyu

On 6/12/2012 12:11 PM, Zhengyu Gu wrote:
> This is the webrev for native memory tracking phase 1, which is 
> tracked by CR6995781 
> (http://monaco.us.oracle.com/detail.jsf?cr=6995781) and related DCmd 
> CR7151532 (http://monaco.us.oracle.com/detail.jsf?cr=7151532).
>
> Native memory tracking (NMT) phase 1, is designed to track native 
> memory (malloc'd and mmap'd) usages by VM code only, it does not track 
> the memory usages by libraries and JNI code.
>
> On the implementation side, NMT intercepts memory related calls in os 
> implementation, such as os::malloc, os::realloc, os::free, 
> os::reserve_memory, os::commit_memory and etc. the caller is required 
> to provide the 'memory type' information, which represents the VM 
> subsystem that the memory is allocated for. The 'memory type' is 
> defined in /src/share/memory/allocation.hpp. Also, a caller's pc is 
> captured if NMT tracking level is set to detail.
>
> There are a few ways to tag a memory block to a memory type:
>
> 1. os::malloc takes an extra parameter for the memory type.
> 2. CHeapObj now is a template, it takes a memory type as template 
> parameter to tag the object to a specified memory type.
> 3. Utility classes, such as Arena, GrowableArray and etc. the memory 
> type is a parameter of 'new' operator.
> 4. Virtual memory block is tagged on its base address.
>
> When NMT intercepts the call, a memory record is created and 
> serialized by a sequence number, generated by global sequence 
> generator. The memory record is written to a per-thread recorder 
> without a  lock, when calling thread is a 'safepoint visible' 
> JavaThread - a JavaThread that will block at safepoint. Otherwise, 
> ThreadCritical lock is acquired to write to a global recorder. The 
> recorders (or raw data) are synchronized at some safepoints, and 
> global sequence generator is also reset at synchronization time, to 
> avoid overflow the sequence number.
>
> A dedicated NMT worker thread is created to process the raw memory 
> records. It first stages a generation of raw data (a generation is 
> defined as span between resets of global sequence number), then 
> promotes the staged data to a global snapshot, which maintains 
> information of all 'live' memory block.
>
> NMT Tracking option has to be specified through VM command line option 
> -XX:NativeMemoryTracking (off by default), tracking level can not be 
> altered during runtime, but it can be shutdown through jcmd tool.
>
> NMT DCmd implements a set of sub-command to control NMT runtime and 
> request tracking data.
>
> Webrev: http://cr.openjdk.java.net/~zgu/6995781/webrev.00
>
> The tests and results:
>
>  - Passed internal smoke tests
>  - JTreg test: http://cr.openjdk.java.net/~zgu/6995781/JTreport/
>
>
> Additional notes:
>   - Some classes' new operators are marked _NOINLINE_ (for the same 
> purpose as above), the performance runs, I performed, indicate that 
> they do not impact performance numbers.
>
>   - SA agent changes are in progress
>
> Thanks,
>
> -Zhengyu
>
>
>
>
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