On Fri, 10 Feb 2017, Michal Hocko wrote:
On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote:The SHM_HUGE_* stuff was introduced in:42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB) It unnecessarily adds another layer, specific to sysv shm, without anything special about it: the macros are identical to the MAP_HUGE_* stuff, which in turn does correctly describe the hugepage subsystem. One example of the problems with extra layers what this patch fixes: mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously harmless but it would still be grand to get rid of it -- although now in the manpages I don't see that happening.Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi headers AFAICS.
Yeah that was my original idea, however I noticed that shmget.2 mentions
kernel internals as part of SHM_HUGE_{2MB,1GB}, ie: SHM_HUGE_SHIFT. So
dropping _MASK doesn't make sense if we are going to keep _SHIFT.
Thanks,
Davidlohr
