On Tue, Jun 10, 2025 at 6:53 AM Brooks Davis <bro...@freebsd.org> wrote: > > On Tue, Jun 10, 2025 at 08:15:02AM +0100, David Chisnall wrote: > > On 10 Jun 2025, at 00:17, Warner Losh <i...@bsdimp.com> wrote: > > > > > > I'm unsure what to do in the future. What are all the cool kids using > > > today? > > > > I???ve replaced jemalloc with snmalloc (to which I am a contributor) in > > libc about five years ago and have been using that on a few places. I > > believe Brooks imported a cleaned-up version of my patches to CheriBSD and > > was planning on upstreaming them as an option. > > > > I've been doing infrastructure work for this as a background task > due to a decision to switch back to a wrapped jemalloc for CheriBSD > heap temporal safety work (at the time we were debugging too many > different things at once and decided that wrapping jemalloc meant we > were debugging fewer things). > > I think we should ship 15.0 with jemalloc, ideally updated to at least > 5.3.0. I'd also like to deprecate all the jemalloc specific symbols for > 15 by removing default versions. I've got a patch to do so, but probably > need an exprun for it and maybe a shim library to allow linkage with > those symbols.
I agree. I have staged this, but am working through a few of the last snags in completely scripting the upgrade so that it's maximally auditable after the xz compromise. While I don't think we have a big risk of that, I think some caution is needed. I like the idea of deprecating the specific symbols... but that's contingent on exprun since I think we do use them in a few ports (or used to, I reviewed something that did years ago). > Longer term, pivoting to a malloc with better hardening is certainly the > right thing to do and snmalloc is a candidate. Yea, we need something that's maintained and still innovating. While malloc is a relatively stable interface, getting good performance out of it for the changing dynamic of applications requires constant study and tuning... I don't know enough to know if snmalloc is the best choice for us or not, but I do think we should be intentional about this and if there's a number of people that can guide the process, so much the better. Warner
