[PATCH 3/4] mm, thp: Add VM_INIT_DEF_MASK and PRCTL_THP_DISABLE
From: Alex Thorlton <hidden>
Date: 2014-02-27 17:23:51
Also in:
linux-mm, linux-s390, lkml
Subsystem:
exec & binfmt api, elf, memory management - core, scheduler, the rest · Maintainers:
Kees Cook, Andrew Morton, David Hildenbrand, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
This patch adds a VM_INIT_DEF_MASK, to allow us to set the default flags for VMs. It also adds a prctl control which alllows 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 <redacted> Suggested-by: Oleg Nesterov <oleg@redhat.com> Cc: Gerald Schaefer <redacted> Cc: Martin Schwidefsky <redacted> Cc: Heiko Carstens <redacted> Cc: Christian Borntraeger <redacted> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Kirill A. Shutemov" <redacted> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <redacted> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <redacted> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <redacted> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux390@de.ibm.com Cc: linux-s390@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-api@vger.kernel.org --- include/linux/mm.h | 3 +++ include/uapi/linux/prctl.h | 3 +++ kernel/fork.c | 11 ++++++++--- kernel/sys.c | 15 +++++++++++++++ 4 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28f46e..0314e4c 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) +/* 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 289760f..58afc04 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 a17621c..9fc0a30 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -529,8 +529,6 @@ 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));
@@ -539,8 +537,15 @@ 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 c0a58be..aa8d3a0 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;
--
1.7.12.4
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