This change includes the following improvements:
- Remove the hpa_sec_batch_fill_extra parameter.
- Refactor the hpa_alloc() code and helper functions to be able to
allocate more than one extent out of a single pageslab. This way
we can amortize the per-pageslab costs (active bitmap iteration,
pageslab metadata updates) across multiple extents.
- Decide on a min and max number of extents that will be allocated
in hpa_alloc(). The code will try to allocate at least the min
and allocate up to the max as long as we can allocate additional
ones from the pageslab we already have, as additional allocations
are relatively cheap.
- Add extent allocation distribution stats.
- Amend hpa_sec_integration.c unit test.
Header files are now self-contained, which makes the relationships
between the files clearer, and crucially allows LSP tools like `clangd`
to function correctly in all of our header files. I have verified that
the headers are self-contained (aside from the various Windows shims) by
compiling them as if they were C files – in a follow-up commit I plan to
add this to CI to ensure we don't regress on this front.
Default SEC max_alloc option value was 32k, disabling SEC for platforms with
lg-page=16. This change enables SEC for all platforms, making minimum max_alloc
value equal to PAGE.
This change pulls the SEC options into a struct, which simplifies their handling
across various modules (e.g. PA needs to forward on SEC options from the
malloc_conf string, but it doesn't really need to know their names). While
we're here, make some of the fixed constants configurable, and unify naming from
the configuration options to the internals.
Tony Printezis