02-12 20:06:18.515 11470-11470/? D/dalvikvm﹕ GC_EXTERNAL_ALLOC freed 3K, 48% free 3188K/6023K, external 7949K/8580K, paused 29ms
02-12 20:06:18.804 11470-11470/? D/dalvikvm﹕ GC_EXTERNAL_ALLOC freed <1K, 48% free 3189K/6023K, external 13255K/13400K, paused 28ms
02-12 20:06:19.406 11470-11470/? D/dalvikvm﹕ GC_EXTERNAL_ALLOC freed <1K, 48% free 3189K/6023K, external 14706K/16754K, paused 56ms
02-12 20:06:19.914 11470-11475/? I/dalvikvm﹕ Total arena pages for JIT: 11
What actually 'arena' is?
You can read about it here or here. In a few words, it is a concept for the memory management in a multithreaded application. Memory is divided into arenas (regions, areas). Each allocation arena has its own lock, so multiple threads don't interfere with each other when they allocate memory at one time.
Why did I see this message? Am I the Chosen One?
No, I don't think so. =) I'm not really sure, but it seems just like an internal warning from the JIT that it has allocated a large number of memory blocks.
Internally this arena-based malloc is built upon a linked list. I.e. each arena is implemented as a linked list of large blocks of memory. The current block (
currentArena) maintains a pointer to the next free position in the block (
&(currentArena->ptr[currentArena->bytesAllocated])), and if the block is filled (see <0>), a new one is allocated (see <1>) and added to the list (see <2>).