On Wed, Aug 23, 2017 at 5:25 PM, Boqun Feng <[email protected]> wrote: > With LOCKDEP_CROSSRELEASE and LOCKDEP_COMPLETIONS introduced, the growth > in kernel stack usage of several functions were reported: > > https://marc.info/?l=linux-kernel&m=150270063231284&w=2 > > The root cause of this is in COMPLETION_INITIALIZER_ONSTACK(), we use > > ({init_completion(&work); work}) > > , which will create a temporary object when returned. However this > temporary object is unnecessary. And this patch fixes it by making the > statement expression in COMPLETION_INITIALIZER_ONSTACK() return a > pointer rather than a whole structure. This will reduce the stack usage > even if !LOCKDEP. > > However, such a change does make one COMPLETION_INITIALIZER_ONSTACK() > callsite invalid, so we fix this first via converting to > init_completion().
Both patches Acked-by: Arnd Bergmann <[email protected]>
