[PATCH] D51539: [clangd] Add symbol slab size to index memory consumption estimates

[Eric Liu via Phabricator via cfe-commits]

ioeric added inline comments.


================
Comment at: clang-tools-extra/clangd/index/FileIndex.cpp:144
+size_t FileIndex::estimateMemoryUsage() const {
+  return FSymbols.estimateMemoryUsage();
+}
----------------
sammccall wrote:
> ioeric wrote:
> > This can be a bit tricky. Generally, the size of a `FileIndex` is the size of FSymbols plus the overhead of the underlying index, but there can be multiple snapshots of symbols in `SwapIndex`. I think we can treat them as burst and only consider the size of the latest snapshot. 
> > 
> > `FSymbols` and the index have shared ownership to the symbol corpus. We can make either of them bookkeep the size, but I think it might be more straightforward to let the index "own" the size. You could set the payload size when creating the index, and you wouldn't need to expose `estimateMemoryUsage` from `FSymbols`.
> (I had trouble parsing this at first - If I understand right, you want the *memIndex* to own the size, and FileIndex to just inherit SwapIndex::estimateMemoryUsage which delegates to MemIndex::estimateMemoryUsage?)
> 
> I like this idea, it's simpler and also means one less place you need to lock, which is always nice.
Yes, that's correct. Thanks for the clarification!


https://reviews.llvm.org/D51539