From a0715cc22601e8830ace98366c0c2bd8da52af52 Mon Sep 17 00:00:00 2001 From: Alex Thorlton Date: Mon, 7 Apr 2014 15:37:10 -0700 Subject: mm, thp: add VM_INIT_DEF_MASK and PRCTL_THP_DISABLE Add VM_INIT_DEF_MASK, to allow us to set the default flags for VMs. It also adds a prctl control which allows us to set the THP disable bit in mm->def_flags so that VMs will pick up the setting as they are created. Signed-off-by: Alex Thorlton Suggested-by: Oleg Nesterov Cc: Gerald Schaefer Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Christian Borntraeger Cc: Paolo Bonzini Cc: "Kirill A. Shutemov" Cc: Mel Gorman Acked-by: Rik van Riel Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Andrea Arcangeli Cc: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Alexander Viro Cc: Johannes Weiner Cc: David Rientjes Cc: Paolo Bonzini Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index adaeab6f7a87..fba0f29401ea 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1996,6 +1996,21 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, if (arg2 || arg3 || arg4 || arg5) return -EINVAL; return current->no_new_privs ? 1 : 0; + case PR_GET_THP_DISABLE: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + error = !!(me->mm->def_flags & VM_NOHUGEPAGE); + break; + case PR_SET_THP_DISABLE: + if (arg3 || arg4 || arg5) + return -EINVAL; + down_write(&me->mm->mmap_sem); + if (arg2) + me->mm->def_flags |= VM_NOHUGEPAGE; + else + me->mm->def_flags &= ~VM_NOHUGEPAGE; + up_write(&me->mm->mmap_sem); + break; default: error = -EINVAL; break; -- cgit v1.2.3-59-g8ed1b