On Tue, Sep 07, 2021 at 02:53:48PM +0000, Chuck Lever III wrote: > > > > On Sep 6, 2021, at 8:41 PM, NeilBrown <neilb@xxxxxxx> wrote: > > > > When does a single-page GFP_KERNEL allocation fail? Ever? > > > > I know that if I add __GFP_NOFAIL then it won't fail and that is > > preferred to looping. > > I know that if I add __GFP_RETRY_MAILFAIL (or others) then it might > > fail. > > But that is the semantics for a plain GFP_KERNEL ?? > > > > I recall a suggestion one that it would only fail if the process was > > being killed by the oom killer. That seems reasonable and would suggest > > that retrying is really bad. Is that true? > > > > For svc_alloc_args(), it might be better to fail and have the calling > > server thread exit. This would need to be combined with dynamic > > thread-count management so that when a request arrived, a new thread > > might be started. > > I don't immediately see a benefit to killing server threads > during periods of memory exhaustion, but sometimes I lack > imagination. Give up parallelism in return for at least hope of forward progress? (Which should be possible as long as there's at least one server thread.) --b.
