[RESEND RFC PATCH v1 02/20] mm: add flag to __ksm_enter
From: Stefan Roesch <hidden>
Date: 2023-01-23 18:06:40
Also in:
linux-doc, linux-fsdevel, linux-kselftest, linux-mm, lkml
Subsystem:
memory management, memory management - ksm (kernel samepage merging), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
This change adds the flag parameter to __ksm_enter. This allows to distinguish if ksm was called by prctl or madvise. Signed-off-by: Stefan Roesch <redacted> --- include/linux/ksm.h | 6 ++++-- mm/ksm.c | 9 +++++---- 2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 7e232ba59b86..50e6b56092f3 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h@@ -18,13 +18,15 @@ #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, unsigned long *vm_flags); -int __ksm_enter(struct mm_struct *mm); void __ksm_exit(struct mm_struct *mm); +int __ksm_enter(struct mm_struct *mm, int flag); static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { + if (test_bit(MMF_VM_MERGE_ANY, &oldmm->flags)) + return __ksm_enter(mm, MMF_VM_MERGE_ANY); if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) - return __ksm_enter(mm); + return __ksm_enter(mm, MMF_VM_MERGEABLE); return 0; }
diff --git a/mm/ksm.c b/mm/ksm.c
index dd02780c387f..d84a244fe224 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c@@ -2493,8 +2493,9 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start, return 0; #endif - if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) { - err = __ksm_enter(mm); + if (!test_bit(MMF_VM_MERGEABLE, &mm->flags) && + !test_bit(MMF_VM_MERGE_ANY, &mm->flags)) { + err = __ksm_enter(mm, MMF_VM_MERGEABLE); if (err) return err; }
@@ -2520,7 +2521,7 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start, } EXPORT_SYMBOL_GPL(ksm_madvise); -int __ksm_enter(struct mm_struct *mm) +int __ksm_enter(struct mm_struct *mm, int flag) { struct ksm_mm_slot *mm_slot; struct mm_slot *slot;
@@ -2553,7 +2554,7 @@ int __ksm_enter(struct mm_struct *mm) list_add_tail(&slot->mm_node, &ksm_scan.mm_slot->slot.mm_node); spin_unlock(&ksm_mmlist_lock); - set_bit(MMF_VM_MERGEABLE, &mm->flags); + set_bit(flag, &mm->flags); mmgrab(mm); if (needs_wakeup)
--
2.30.2