On 06/09/2018 01:01, Thomas Gleixner wrote: > On Wed, 5 Sep 2018, Laurent Dufour wrote: >> On 05/09/2018 17:10, Christopher Lameter wrote: >>> Large page sizes also reduce contention there. >> >> That's true for the page fault path, but for process's actions manipulating the >> memory process's layout (mmap,munmap,madvise,mprotect) the impact is minimal >> unless the code has to manipulate the page tables. > > And how exactly are you going to do any of those operations _without_ > manipulating the page tables? I agree, at one time the page tables would have to be manipulated, and this is mostly done under the protection of the page table locks - should the mmap_sem still being held then ? I was thinking about all the processing done on the VMAs, accounting, etc. That part, usually not manipulating the page tables, is less dependent of the underlying page size. But I agree at one time of the processing, the page table are manipulated and dealing with larger pages is better then. Thanks, Laurent.
