Hi,
On Sunday, 07.02.2021, 01:54 +0100 Paul Boddie wrote:
What considerations need to be given to concurrency with regard to the use of the l4re_rm_attach function and similar functionality? Is access to the region mapper/manager from different threads in the same task advisable, are there thread safety issues, and if so, can these be sensibly worked around?
Calls to the region manager are IPC calls and are synchronized by a wait-queue in the kernel. The region manager thread only serves one client at a time. In fact if you use multiple threads in a task it serves all page-faults for all threads already. It's thread-safe by design.
However, the capability slot allocator (l4re_util_cap_alloc) is not thread-safe. You need to introduce some synchronization if you use it from multiple threads.
Hope that helps.
- Christian