The patch titled
Subject: mm/ksm: move disabling KSM from s390/gmap code to KSM code
has been added to the -mm mm-unstable branch. Its filename is
mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/ksm: move disabling KSM from s390/gmap code to KSM code
Date: Sat, 22 Apr 2023 23:01:56 +0200
Let's factor out actual disabling of KSM. The existing "mm->def_flags &=
~VM_MERGEABLE;" was essentially a NOP and can be dropped, because
def_flags should never include VM_MERGEABLE. Note that we don't currently
prevent re-enabling KSM.
This should now be faster in case KSM was never enabled, because we only
conditionally iterate all VMAs. Further, it certainly looks cleaner.
Link: https://lkml.kernel.org/r/20230422210156.33630-1-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Acked-by: Stefan Roesch <shr@xxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/gmap.c | 20 +-------------------
include/linux/ksm.h | 6 ++++++
mm/ksm.c | 11 +++++++++++
3 files changed, 18 insertions(+), 19 deletions(-)
--- a/arch/s390/mm/gmap.c~mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code
+++ a/arch/s390/mm/gmap.c
@@ -2585,30 +2585,12 @@ EXPORT_SYMBOL_GPL(s390_enable_sie);
int gmap_mark_unmergeable(void)
{
- struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
- unsigned long vm_flags;
- int ret;
- VMA_ITERATOR(vmi, mm, 0);
-
/*
* Make sure to disable KSM (if enabled for the whole process or
* individual VMAs). Note that nothing currently hinders user space
* from re-enabling it.
*/
- clear_bit(MMF_VM_MERGE_ANY, &mm->flags);
-
- for_each_vma(vmi, vma) {
- /* Copy vm_flags to avoid partial modifications in ksm_madvise */
- vm_flags = vma->vm_flags;
- ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
- MADV_UNMERGEABLE, &vm_flags);
- if (ret)
- return ret;
- vm_flags_reset(vma, vm_flags);
- }
- mm->def_flags &= ~VM_MERGEABLE;
- return 0;
+ return ksm_disable(current->mm);
}
EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
--- a/include/linux/ksm.h~mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code
+++ a/include/linux/ksm.h
@@ -22,6 +22,7 @@ int ksm_madvise(struct vm_area_struct *v
void ksm_add_vma(struct vm_area_struct *vma);
int ksm_enable_merge_any(struct mm_struct *mm);
int ksm_disable_merge_any(struct mm_struct *mm);
+int ksm_disable(struct mm_struct *mm);
int __ksm_enter(struct mm_struct *mm);
void __ksm_exit(struct mm_struct *mm);
@@ -80,6 +81,11 @@ static inline void ksm_add_vma(struct vm
{
}
+static inline int ksm_disable(struct mm_struct *mm)
+{
+ return 0;
+}
+
static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
{
return 0;
--- a/mm/ksm.c~mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code
+++ a/mm/ksm.c
@@ -2628,6 +2628,17 @@ int ksm_disable_merge_any(struct mm_stru
return 0;
}
+int ksm_disable(struct mm_struct *mm)
+{
+ mmap_assert_write_locked(mm);
+
+ if (!test_bit(MMF_VM_MERGEABLE, &mm->flags))
+ return 0;
+ if (test_bit(MMF_VM_MERGE_ANY, &mm->flags))
+ return ksm_disable_merge_any(mm);
+ return ksm_del_vmas(mm);
+}
+
int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
unsigned long end, int advice, unsigned long *vm_flags)
{
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0.patch
selftests-ksm-ksm_functional_tests-add-prctl-unmerge-test.patch
mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code.patch
