On Thu, 29 May 2014, David Rientjes wrote: > When I said that my point about mempolicies needs more thought, I wasn't > expecting that there would be no discussion -- at least _something_ that > would say why we don't care about the mempolicy case.
Lets get Andi involved here too. > The motivation here is identical for both cpusets and mempolicies. What > is the significant difference between attaching a process to a cpuset > without access to lowmem and a process doing set_mempolicy(MPOL_BIND) > without access to lowmem? Is it because the process should know what it's > doing if it asks for a mempolicy that doesn't include lowmem? If so, is > the cpusets case different because the cpuset attacher isn't held to the > same standard? > > I'd argue that an application may never know if it needs to allocate > GFP_DMA32 or not since its a property of the hardware that its running on > and my driver may need to access lowmem while yours may not. I may even > configure CONFIG_ZONE_DMA=n and CONFIG_ZONE_DMA32=n because I know the > _hardware_ requirements of my platforms. Right. This is a hardware issue and the hardware is pretty messed up. And now one wants to use NUMA features? > If there is no difference, then why are we allowing the exception for > cpusets and not mempolicies? > > I really think you want to allow both cpusets and mempolicies. I'd like > to hear Christoph's thoughts on it as well, though. I said something elsewhere in the thread. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/