diff options
| -rw-r--r-- | include/linux/mm.h | 3 | ||||
| -rw-r--r-- | include/uapi/linux/prctl.h | 3 | ||||
| -rw-r--r-- | kernel/fork.c | 11 | ||||
| -rw-r--r-- | kernel/sys.c | 15 |
4 files changed, 29 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 35300f390eb..c270fa68a32 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -177,6 +177,9 @@ extern unsigned int kobjsize(const void *objp); */ #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP) +/* This mask defines which mm->def_flags a process can inherit its parent */ +#define VM_INIT_DEF_MASK VM_NOHUGEPAGE + /* * mapping from the currently active vm_flags protection bits (the * low four bits) to a page protection mask.. diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 289760f424a..58afc04c107 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -149,4 +149,7 @@ #define PR_GET_TID_ADDRESS 40 +#define PR_SET_THP_DISABLE 41 +#define PR_GET_THP_DISABLE 42 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/fork.c b/kernel/fork.c index abc45890f0a..e40c0a01d5a 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -530,8 +530,6 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) atomic_set(&mm->mm_count, 1); init_rwsem(&mm->mmap_sem); INIT_LIST_HEAD(&mm->mmlist); - mm->flags = (current->mm) ? - (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; mm->core_state = NULL; atomic_long_set(&mm->nr_ptes, 0); memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); @@ -540,8 +538,15 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) mm_init_owner(mm, p); clear_tlb_flush_pending(mm); - if (likely(!mm_alloc_pgd(mm))) { + if (current->mm) { + mm->flags = current->mm->flags & MMF_INIT_MASK; + mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; + } else { + mm->flags = default_dump_filter; mm->def_flags = 0; + } + + if (likely(!mm_alloc_pgd(mm))) { mmu_notifier_mm_init(mm); return mm; } diff --git a/kernel/sys.c b/kernel/sys.c index adaeab6f7a8..fba0f29401e 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; |