[PATCH] D39464: Define fs::allocate_file which preallocates disk blocks.

[Rafael Avila de Espindola via llvm-commits]

Joerg Sonnenberger via Phabricator <reviews at reviews.llvm.org> writes:

> joerg added a comment.
>
> I really dislike this direction. fallocate can double the amount of disk IO and increase cache trashing, especially when linking large programs with debug information. Keeping more things in memory doesn't sound like an actual improvement either. If the goal is really only to improve the diagnostics in tools, I think a better idea would be to figure out a good way to handle this from a SIGBUS handler based on the passed in siginfo_t.

fallocate is really fast on modern filesystems.

I really don't want to get lld into the business of handling SIGBUS.

Cheers,
Rafael