On Mon 17-10-16 17:55:40, Kirill A. Shutemov wrote: > On Mon, Oct 17, 2016 at 04:12:46PM +0200, Michal Hocko wrote: > > On Mon 17-10-16 15:30:21, Kirill A. Shutemov wrote: [...] > > > We add two handle to specify minimal file size for huge pages: > > > > > > - mount option 'huge_min_size'; > > > > > > - sysfs file /sys/kernel/mm/transparent_hugepage/shmem_min_size for > > > in-kernel tmpfs mountpoint; > > > > Could you explain who might like to change the minimum value (other than > > disable the feautre for the mount point) and for what reason? > > Depending on how well CPU microarchitecture deals with huge pages, you > might need to set it higher in order to balance out overhead with benefit > of huge pages.
I am not sure this is a good argument. How do a user know and what will help to make that decision? Why we cannot autotune that? In other words, adding new knobs just in case turned out to be a bad idea in the past. > In other case, if it's known in advance that specific mount would be > populated with large files, you might want to set it to zero to get huge > pages allocated from the beginning. Cannot we use [mf]advise for that purpose? -- Michal Hocko SUSE Labs