Messages in this thread | | | Date | Tue, 27 Feb 2018 19:11:25 +1000 | From | Nicholas Piggin <> | Subject | Re: [RFC REBASED 5/5] powerpc/mm/slice: use the dynamic high slice size to limit bitmap operations |
| |
On Tue, 27 Feb 2018 14:31:07 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> Christophe Leroy <christophe.leroy@c-s.fr> writes: > > > The number of high slices a process might use now depends on its > > address space size, and what allocation address it has requested. > > > > This patch uses that limit throughout call chains where possible, > > rather than use the fixed SLICE_NUM_HIGH for bitmap operations. > > This saves some cost for processes that don't use very large address > > spaces. > > I haven't really looked at the final code. One of the issue we had was > with the below scenario. > > mmap(addr, len) where addr < 128TB and addr+len > 128TB We want to make > sure we build the mask such that we don't find the addr available.
We should run it through the mmap regression tests. I *think* we moved all of that logic from the slice code to get_ummapped_area before going in to slices. I may have missed something though, it would be good to have more eyes on it.
Thanks, Nick
| |