On Tue, May 18, 2021 at 07:21:33AM -0400, Jeff Hostetler wrote: > > In the simple-ipc API, there's an explicit "async" interface. But it's > > not clear to me how rich it expects the communication with the caller to > > be (i.e., whether we could get away with the fork() trick here). Or if > > it would be OK for the threading to remain an implementation detail, > > with one "worker" upon whom we wait for completion. > > > > TBH I forgot that we still support NO_PTHREAD systems. > I seem to remember that we got rid of some of the non-pthread > stub functions at one point, but I'm fuzzy on the details. You're probably thinking of when we got rid of a bunch of #ifdef code paths in index-pack, and replaced it with stubs that turn the pthread calls into "do nothing" (so all the ugly stuff is in thread-utils.h now). But we still very much support systems that don't handle pthreads at all. > WRT to "simple ipc" (and future "builtin fsmonitor"), it's heavily > threaded. There's no point in trying to fake it with forks. > > The server side of simple ipc implements a thread pool. And > the builtin fsmonitor will use a thread to monitor FS events > and that thread pool to respond to clients. All driven from a > shared queue of events. > > It would be a major overhaul to do all that without threads > -- and even that assumes that nonstop has a sufficient file > system notification mechanism. OK, that matches my guess from a brief look at the code. Thanks for confirming. > So, yes, we should ifdef it out as Peff suggests. The patch I sent wasn't really tested beyond confirming that "make NO_PTHREADS=1" finished compiling (and that test-tool simple-ipc barfed appropriately at runtime). Do you want to pick it up from there and produce a polished patch? I think we should deal with this prior to the v2.32.0 release (and thanks Randall for testing and finding it during the -rc0 period). -Peff
