let's use a fixed number of threads for libpager

Hello :) this is a new patch that makes libpager use a fixed number of threads, currently one (plus one receiving messages and enqueuing them into a userspace queue). If our store interface improves, we can increase the number of worker threads (the work delegation uses a linear scan over the wor

[PATCH hurd] libpager: use a fixed number of threads

Previously, libpager used an unbounded number of threads to receive messages from the pager bucket. It used sequence barriers to execute the requests to order requests to each object. The sequence barriers are implemented in seqnos.c. A server function uses _pager_wait_for_seqno to wait for its