[PATCH RFC 2/5] mm/ksm: introduce ksm_madvise_merge() helper
flat view
STALE2709d
From: Oleksandr Natalenko <hidden>
Date: 2019-05-16 09:42:45
Also in:
linux-mm, lkml
Subsystem:
memory management, memory management - ksm (kernel samepage merging), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Move MADV_MERGEABLE part of ksm_madvise() into a dedicated helper since it will be further used for marking VMAs to be merged forcibly. This does not bring any functional changes. Signed-off-by: Oleksandr Natalenko <redacted> --- include/linux/ksm.h | 2 ++ mm/ksm.c | 60 +++++++++++++++++++++++++++------------------ 2 files changed, 38 insertions(+), 24 deletions(-)
diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index e48b1e453ff5..e824b3141677 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h@@ -19,6 +19,8 @@ struct stable_node; struct mem_cgroup; #ifdef CONFIG_KSM +int ksm_madvise_merge(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long *vm_flags); 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);
diff --git a/mm/ksm.c b/mm/ksm.c
index fc64874dc6f4..1fdcf2fbd58d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c@@ -2442,41 +2442,53 @@ static int ksm_scan_thread(void *nothing) return 0; } -int ksm_madvise(struct vm_area_struct *vma, unsigned long start, - unsigned long end, int advice, unsigned long *vm_flags) +int ksm_madvise_merge(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long *vm_flags) { - struct mm_struct *mm = vma->vm_mm; int err; - switch (advice) { - case MADV_MERGEABLE: - /* - * Be somewhat over-protective for now! - */ - if (*vm_flags & (VM_MERGEABLE | VM_SHARED | VM_MAYSHARE | - VM_PFNMAP | VM_IO | VM_DONTEXPAND | - VM_HUGETLB | VM_MIXEDMAP)) - return 0; /* just ignore the advice */ + /* + * Be somewhat over-protective for now! + */ + if (*vm_flags & (VM_MERGEABLE | VM_SHARED | VM_MAYSHARE | + VM_PFNMAP | VM_IO | VM_DONTEXPAND | + VM_HUGETLB | VM_MIXEDMAP)) + return 0; /* just ignore the advice */ - if (vma_is_dax(vma)) - return 0; + if (vma_is_dax(vma)) + return 0; #ifdef VM_SAO - if (*vm_flags & VM_SAO) - return 0; + if (*vm_flags & VM_SAO) + return 0; #endif #ifdef VM_SPARC_ADI - if (*vm_flags & VM_SPARC_ADI) - return 0; + if (*vm_flags & VM_SPARC_ADI) + return 0; #endif - if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) { - err = __ksm_enter(mm); - if (err) - return err; - } + if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) { + err = __ksm_enter(mm); + if (err) + return err; + } + + *vm_flags |= VM_MERGEABLE; + + return 0; +} - *vm_flags |= VM_MERGEABLE; +int ksm_madvise(struct vm_area_struct *vma, unsigned long start, + unsigned long end, int advice, unsigned long *vm_flags) +{ + struct mm_struct *mm = vma->vm_mm; + int err; + + switch (advice) { + case MADV_MERGEABLE: + err = ksm_madvise_merge(mm, vma, vm_flags); + if (err) + return err; break; case MADV_UNMERGEABLE:
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2.21.0