Review Request: 8011872: Include Bit Map addresses in the hs_err files

[Bengt Rutisson]

Stefan,

Looks good!

Thanks for fixing this, I think it will be very useful!

Bengt

On 4/10/13 4:58 PM, Stefan Karlsson wrote:
> http://cr.openjdk.java.net/~stefank/8011872/webrev.00/
>
> I propose that we start logging the placement of the bitmaps hs_err 
> crash files.
>
> This will help identifies bugs where we have memory trashing in the 
> bitmaps. Today, we have this kind of information for the card table 
> but it's lacking for the bitmaps.
>
> Example outputs:
>
> -XX:+UseParallelOldGC:
> Marking Bits: (ParMarkBitMap*) 0x00007ffff73a85e0
>  Begin Bits: [0x00007fffe4200000, 0x00007fffe60b8000)
>  End Bits:   [0x00007fffe60b8000, 0x00007fffe7f70000)
>
> -XX:+UseG1GC:
> Marking Bits (Prev, Next): (CMBitMap*) 0x00007ffff0059628, (CMBitMap*) 
> 0x00007ffff00596c0
>  Prev Bits: [0x00007fffc5290000, 0x00007fffc7148000)
>  Next Bits: [0x00007fffa2147000, 0x00007fffa3fff000)
>
> -XX:+UseConcMarkSweepGC:
> Marking Bits: (CMSBitMap*) 0x00007ffff00b0ee8
>  Bits: [0x00007fffce7f1000, 0x00007fffcfc6e800)
>
> Mod Union Table: (CMSBitMap*) 0x00007ffff00b0f88
>  Bits: [0x00007ffff405c000, 0x00007ffff40adf60)
>
> Note that for simplicity this logs the memory used by the low level 
> datastructure BitMap, and not the memory allocated in the GC specific 
> bitmap data structures (E.g. CMBitMap). What this means is that we 
> actually allocate up to about os::vm_allocation_granularity() more 
> memoy at the end of the bitmap. If this information is essential we 
> can add it later.
>
> thanks,
> StefanK