Sneak per-GrBlockAllocator user-controlled metadata into head block
Previously, the blocks owned by a GrBlockAllocator provided block-level
metadata that users could control to track within a block. For types
like GrTAllocator (and a collection coming down the pipe), they need
to store a total count of allocations.
Since GrBlockAllocator is max-aligned, having them hold on to a single
extra int adds 4 to 12 bytes of padding for 8 and 16byte aligned
platforms. But, the old Block size already has 4 bytes of extra padding
since it was 28 bytes packed. This had been allowed to be allocation
data, for requests that were 4-byte aligned or less.
In practice, I think it's better to use that space for allocator-level
metadata so that a total count, or other high-level data, can be
packed into the data already held by GrBlockAllocator. Now GrTAllocator
instances should be 8-16 bytes smaller on those same platforms. Also
no longer writing into the struct-padded nether-realm, which is probably
just a good thing on principle.
Also cleans up how GrTAllocator's push_back() and emplace_back() are
tested to make sure all options are clearly covered.
Change-Id: If1da29132f3ec8df7a4056fcd834f760eb4693f5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/303267
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed