Question about SHM_QUEUE

Hello,

I have a question about SHM_QUEUE. Why do we need this component?

We've already made some modules under the assumption that the base offset
of shared memory is mapped to the same address for all processes.
See comment in freespace.h:

* Note: we handle pointers to these items as pointers, not as SHMEM_OFFSETs.
* This assumes that all processes accessing the map will have the shared
* memory segment mapped at the same place in their address space.

Then, can we replace SHM_QUEUE by a pointer-based double-linked list?
It will be an "intrusive" version of Dllist.

Regards,
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ITAGAKI Takahiro
NTT Open Source Software Center