Files
scylladb/test/boost
Avi Kivity 6c797587c7 dirty_memory_manager: region_group: remove sorting of subgroups
dirty_memory_manager tracks lsa regions (memtables) under region_group:s,
in order to be able to pick up the largest memtable as a candidate for
flushing.

Just as region_group:s contain regions, they can also contain other
region_group:s in a nested structure. It also tracks the nested region_group
that contains the largest region in a binomial heap.

This latter facility is no longer used. It saw use when we had the system
dirty_memory_manager nested under the user dirty_memory_manager, but
that proved too complicated so it was undone. We still nest a virtual
region_group under the real region_group, and in fact it is the
virtual region_group that holds the memtables, but it is accessed
directly to find the largest memtable (region_group::get_largest_region)
and so all the mechanism that sorts region_group:s is bypassed.

Start to dismantle this house of cards by removing the subgroup
sorting. Since the hierarchy has exactly one parent and one child,
it's clearly useless. This is seen by the fact that we can just remove
everything related.

We still need the _subgroups member to hold the virtual region_group;
it's replaced by a vector. I verified that the non-intrusive vector
is exception safe since push_back() happens at the very end; in any
case this is early during setup where we aren't under memory pressure.

A few tests that check the removed functionality are deleted.

Closes #11515
2022-09-12 09:29:08 +03:00
..
2022-06-22 20:16:48 +02:00
2022-05-11 16:49:31 +02:00
2022-07-27 16:58:52 +03:00