Interpretation of bit patters in arena_chunk_map_bits_s

Jason Evans jasone at
Tue Mar 8 13:09:46 PST 2016

On Mar 8, 2016, at 11:33 AM, Yasaswini G <yasaswinig7 at> wrote:
> Hi,
> What does the three patterns signify under each one of the allocation type (unallocated(dirty/clean), small, large)  in "arena_chunk_map_bits_s"
> I understand the allocation types (unallocated, small, large),  but I am not sure why there are three different patters under each allocation type.
> For example under Unallocated (clean), we have following bit patterns: 
>      Unallocated (clean):
>      *     ssssssss ssssssss sss+++++ +++dum-a         - pattern1

The above corresponds to the first page within a run.

>      *     xxxxxxxx xxxxxxxx xxxxxxxx xxx-Uxxx             - pattern2

The above corresponds to an interior page within a run.

>      *     ssssssss ssssssss sss+++++ +++dUm-a         - pattern3

The above corresponds to the last page within a run.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the jemalloc-discuss mailing list