Previously, tcache fill/flush (as well as small alloc/dalloc on the arena) may
potentially drop the bin lock for slab_alloc and slab_dalloc. This commit
refactors the logic so that the slab calls happen in the same function / level
as the bin lock / unlock. The main purpose is to be able to use flat combining
without having to keep track of stack state.
In the meantime, this change reduces the locking, especially for slab_dalloc
calls, where nothing happens after the call.
Check the is_head state before merging two extents. Disallow the merge if it's
crossing two separate mmap regions. This enforces first-fit (by not losing the
SN) at a very small cost.
Make the event module to accept two event types, and pass around the event
context. Use bytes-based events to trigger tcache GC on deallocation, and get
rid of the tcache ticker.
- NetBSD overcommits
- When mapping pages, use the maximum of the alignment requested and the
compiled-in PAGE constant which might be greater than the current kernel
pagesize, since we compile binaries with the maximum page size supported
by the architecture (so that they work with all kernels).
Add options stats_interval and stats_interval_opts to allow interval based stats
printing. This provides an easy way to collect stats without code changes,
because opt.stats_print may not work (some binaries never exit).
Eventually, we may fully break off the extent module; but not for some time. If
it's going to live on in a non-transitory state, it might as well have the nicer
name.
What we call an arena_ind is really the index associated with some particular
set of ehooks; the arena is just the user-visible portion of that. Making this
explicit, and reframing checks in terms of that, makes the code simpler and
cleaner, and helps us avoid passing the arena itself all throughout extent code.
This lets us put back an arena-specific assert.
