On Thu, 17 Nov 2016 13:54:27 +0000 (UTC) Mathieu Desnoyers <mathieu.desnoy...@efficios.com> wrote:
> >> > > >> > Acked-by: Lai Jiangshan <jiangshan...@gmail.com> > >> > > >> > But I'm afraid, in the future, tick_nohz_full will become a default y > >> > feature. thus it makes sys_membarrier() always disabled. we might > >> > need a new MEMBARRIER_CMD_XXX to handle it? > >> > >> This may require that we send an IPI to nohz_full CPUs, which will > >> disturb them real-time wise. Any better ideas ? > > > > Restrict the IPIs to CPUs running the process executing the > > sys_membarrier() system call. This would mean that CPUs only > > are interrupted by their own application's request. > > This would break use-cases of cross-process shared memory. :-( Perhaps make this an opt in. That is, all processes that want to be affected by this can call this function with some flag that sets a flag in tasks struct. And have that process get an IPI even in no-hz-full mode if it asked to do it. -- Steve
