psset_pick_purge used max_bit-- after rejecting a time-ineligible
candidate, which caused unnecessary re-scanning of the same bitmap
and makes assert fail in debug mode) and a size_t underflow
when the lowest-index entry was rejected. Use max_bit = ind - 1
to skip directly past the rejected index.
Next to its use, which is always as an argument, we include the name
of the parameter in a constant. This completes a partially
implemented cleanup suggested in an earlier commit.
When hugepage is enabled and PAGESIZE is large, the test could
ask for a stack size larger than user limit. Allocating the
memory instead can avoid the failure.
Closes: #2408
When evaluating changes in HPA logic, it is useful to know internal
`hpa_shard` state. Great deal of this state is `psset`. Some of the
`psset` stats was available, but in disaggregated form, which is not
very convenient. This commit exposed `psset` counters to `mallctl`
and malloc stats dumps.
Example of how malloc stats dump will look like after the change.
HPA shard stats:
Pageslabs: 14899 (4354 huge, 10545 nonhuge)
Active pages: 6708166 (2228917 huge, 4479249 nonhuge)
Dirty pages: 233816 (331 huge, 233485 nonhuge)
Retained pages: 686306
Purge passes: 8730 (10 / sec)
Purges: 127501 (146 / sec)
Hugeifies: 4358 (5 / sec)
Dehugifies: 4 (0 / sec)
Pageslabs, active pages, dirty pages and retained pages are rows added
by this change.
We're moving towards a world in which purging decisions are less rigidly
enforced at a single-hugepage level. In that world, it makes sense to keep
around some hpdatas which are not completely purged, in which case we'll need to
track them.
Really, this isn't a functional change, just a naming change. We start thinking
of pageslabs as being always in the psset. What we used to think of as removal
is now thought of as being in the psset, but in the process of being updated
(and therefore, unavalable for serving new allocations).
This is in preparation of subsequent changes to support deferred purging;
allocations will still be in the psset for the purposes of choosing when to
purge, but not for purposes of allocation/deallocation.
This is really only useful for human consumption. Correspondingly, emit it only
in the human-readable stats, and let everybody else compute from the hugepage
size and nactive.
This is no longer part of the "core" functionality; we only need the stub
implementations as an end-to-end test of hpdata + psset interactions when
metadata is being modified. Treat them accordingly.
Using an edata_t both for hugepages and the allocations within those hugepages
was convenient at first, but has outlived its usefulness. Representing
hugepages explicitly, with their own data structure, will make future
development easier.
This functions more like the serial number strategy of the ecache and
hpa_central_t. Longer-lived slabs are more likely to continue to live for
longer in the future.
This introduces a new sort of edata_t; a pageslab, and a set to manage them.
This is part of a series of a commits to implement a hugepage allocator; the
pageset will be per-arena, and track small page allocations requests within a
larger extent allocated from a centralized hugepage allocator.
