On Wed, 3 May 2023 08:09:28 -0700
Suren Baghdasaryan [off-list ref] wrote:

There is another issue, which I think can be solved in a smart way but
will either affect performance or would require more memory. With the
tracing approach we don't know beforehand how many individual
allocation sites exist, so we have to allocate code tags (or similar
structures for counting) at runtime vs compile time. We can be smart
about it and allocate in batches or even preallocate more than we need
beforehand but, as I said, it will require some kind of compromise.

This approach is actually quite common, especially since tagging every
instance is usually overkill, as if you trace function calls in a running
kernel, you will find that only a small percentage of the kernel ever
executes. It's possible that you will be allocating a lot of tags that will
never be used. If run time allocation is possible, that is usually the
better approach.

-- Steve