Messages in this thread Patches in this message | | | Date | Sat, 08 Nov 2014 03:58:09 +0300 | From | Timofey Titovets <> | Subject | [RFC PATCH] KSM: Auto add flag new VMA as VM_MERGEABLE |
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Hi list.
This is a small patch what allow ksm dedupe "whole" system memory. I think what people with tiny pc and android developers will be happy after this patch. I just like clear memory =].
I have tested it and it working very good. For testing apply it and enable ksm: echo 1 | sudo tee /sys/kernel/mm/ksm/run This show how much memory saved: echo $[$(cat /sys/kernel/mm/ksm/pages_shared)*$(getconf PAGE_SIZE)/1024 ]KB
(i use linux-next-git 20141031)
It add very small overhead to mmap call's.
Please check my code, may be i should move new functions to other file? I think about sysfs switcher like: /sys/kernel/mm/ksm/mark_new_vma # 0 or 1 if 1 new vma will be marked like VM_MERGEABLE.
Can you advise me something?
I implement 2 new functions: ksm_vm_flags_mod() - working only in mm/mmap.c file, change default flags ksm_vma_add_new() - add new created vma to ksm internal tree
If you see broken patch lines i have also attach patch.
From db8ad0877146a69e1e5d5ab98825cefcf44a95bb Mon Sep 17 00:00:00 2001 From: Timofey Titovets <nefelim4ag@gmail.com> Date: Sat, 8 Nov 2014 03:02:52 +0300 Subject: [PATCH] KSM: Add auto flag new VMA as VM_MERGEABLE
Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com> --- include/linux/ksm.h | 31 +++++++++++++++++++++++++++++++ mm/mmap.c | 17 +++++++++++++++++ 2 files changed, 48 insertions(+)
diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 3be6bb1..c3fff64 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -76,6 +76,29 @@ struct page *ksm_might_need_to_copy(struct page *page, int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc); void ksm_migrate_page(struct page *newpage, struct page *oldpage);
+/* + * Allow to mark new vma as VM_MERGEABLE + */ +#ifndef VM_SAO +#define VM_SAO 0 +#endif +static inline void ksm_vm_flags_mod(unsigned long *vm_flags) +{ + if (*vm_flags & (VM_MERGEABLE | VM_SHARED | VM_MAYSHARE | + VM_PFNMAP | VM_IO | VM_DONTEXPAND | + VM_HUGETLB | VM_NONLINEAR | VM_MIXEDMAP | VM_SAO) ) + return; + *vm_flags |= VM_MERGEABLE; +} + +static inline void ksm_vma_add_new(struct vm_area_struct *vma) +{ + struct mm_struct *mm = vma->vm_mm; + if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) { + __ksm_enter(mm); + } +} + #else /* !CONFIG_KSM */
static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) @@ -92,6 +115,14 @@ static inline int PageKsm(struct page *page) return 0; }
+static inline void ksm_vm_flags_mod(unsigned long *vm_flags_p) +{ +} + +void ksm_vma_add_new(struct vm_area_struct *vma) +{ +} + #ifdef CONFIG_MMU static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, unsigned long *vm_flags) diff --git a/mm/mmap.c b/mm/mmap.c index 7f85520..ce0073e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -41,6 +41,7 @@ #include <linux/notifier.h> #include <linux/memory.h> #include <linux/printk.h> +#include <linux/ksm.h>
#include <asm/uaccess.h> #include <asm/cacheflush.h> @@ -911,10 +912,14 @@ again: remove_next = 1 + (end > next->vm_end); vma_gap_update(next); else mm->highest_vm_end = end; + } else { + if (next && !insert) + ksm_vma_add_new(next); } if (insert && file) uprobe_mmap(insert);
+ ksm_vma_add_new(vma); validate_mm(mm);
return 0; @@ -1307,6 +1312,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+ /* If ksm is enabled, we add VM_MERGABLE to new VMAs. */ + ksm_vm_flags_mod(&vm_flags); + if (flags & MAP_LOCKED) if (!can_do_mlock()) return -EPERM; @@ -1648,6 +1656,7 @@ munmap_back: allow_write_access(file); } file = vma->vm_file; + ksm_vma_add_new(vma); out: perf_event_mmap(vma);
@@ -2484,6 +2493,8 @@ static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, else err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
+ ksm_vma_add_new(vma); + /* Success. */ if (!err) return 0; @@ -2659,6 +2670,9 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) if (error) return error;
+ /* If ksm is enabled, we add VM_MERGABLE to new VMAs. */ + ksm_vm_flags_mod(&flags); + /* * mm->mmap_sem is required to protect against another thread * changing the mappings in case we sleep. @@ -2708,6 +2722,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) vma->vm_flags = flags; vma->vm_page_prot = vm_get_page_prot(flags); vma_link(mm, vma, prev, rb_link, rb_parent); + ksm_vma_add_new(vma); out: perf_event_mmap(vma); mm->total_vm += len >> PAGE_SHIFT; @@ -2887,6 +2902,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, new_vma->vm_ops->open(new_vma); vma_link(mm, new_vma, prev, rb_link, rb_parent); *need_rmap_locks = false; + ksm_vma_add_new(new_vma); } } return new_vma; @@ -3004,6 +3020,7 @@ static struct vm_area_struct *__install_special_mapping( mm->total_vm += len >> PAGE_SHIFT;
perf_event_mmap(vma); + ksm_vma_add_new(vma);
return vma;
-- 2.1.3 From db8ad0877146a69e1e5d5ab98825cefcf44a95bb Mon Sep 17 00:00:00 2001 From: Timofey Titovets <nefelim4ag@gmail.com> Date: Sat, 8 Nov 2014 03:02:52 +0300 Subject: [PATCH] KSM: Add auto flag new VMA as VM_MERGEABLE
Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com> --- include/linux/ksm.h | 31 +++++++++++++++++++++++++++++++ mm/mmap.c | 17 +++++++++++++++++ 2 files changed, 48 insertions(+)
diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 3be6bb1..c3fff64 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -76,6 +76,29 @@ struct page *ksm_might_need_to_copy(struct page *page, int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc); void ksm_migrate_page(struct page *newpage, struct page *oldpage); +/* + * Allow to mark new vma as VM_MERGEABLE + */ +#ifndef VM_SAO +#define VM_SAO 0 +#endif +static inline void ksm_vm_flags_mod(unsigned long *vm_flags) +{ + if (*vm_flags & (VM_MERGEABLE | VM_SHARED | VM_MAYSHARE | + VM_PFNMAP | VM_IO | VM_DONTEXPAND | + VM_HUGETLB | VM_NONLINEAR | VM_MIXEDMAP | VM_SAO) ) + return; + *vm_flags |= VM_MERGEABLE; +} + +static inline void ksm_vma_add_new(struct vm_area_struct *vma) +{ + struct mm_struct *mm = vma->vm_mm; + if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) { + __ksm_enter(mm); + } +} + #else /* !CONFIG_KSM */ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) @@ -92,6 +115,14 @@ static inline int PageKsm(struct page *page) return 0; } +static inline void ksm_vm_flags_mod(unsigned long *vm_flags_p) +{ +} + +void ksm_vma_add_new(struct vm_area_struct *vma) +{ +} + #ifdef CONFIG_MMU static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, unsigned long *vm_flags) diff --git a/mm/mmap.c b/mm/mmap.c index 7f85520..ce0073e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -41,6 +41,7 @@ #include <linux/notifier.h> #include <linux/memory.h> #include <linux/printk.h> +#include <linux/ksm.h> #include <asm/uaccess.h> #include <asm/cacheflush.h> @@ -911,10 +912,14 @@ again: remove_next = 1 + (end > next->vm_end); vma_gap_update(next); else mm->highest_vm_end = end; + } else { + if (next && !insert) + ksm_vma_add_new(next); } if (insert && file) uprobe_mmap(insert); + ksm_vma_add_new(vma); validate_mm(mm); return 0; @@ -1307,6 +1312,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + /* If ksm is enabled, we add VM_MERGABLE to new VMAs. */ + ksm_vm_flags_mod(&vm_flags); + if (flags & MAP_LOCKED) if (!can_do_mlock()) return -EPERM; @@ -1648,6 +1656,7 @@ munmap_back: allow_write_access(file); } file = vma->vm_file; + ksm_vma_add_new(vma); out: perf_event_mmap(vma); @@ -2484,6 +2493,8 @@ static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, else err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); + ksm_vma_add_new(vma); + /* Success. */ if (!err) return 0; @@ -2659,6 +2670,9 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) if (error) return error; + /* If ksm is enabled, we add VM_MERGABLE to new VMAs. */ + ksm_vm_flags_mod(&flags); + /* * mm->mmap_sem is required to protect against another thread * changing the mappings in case we sleep. @@ -2708,6 +2722,7 @@ static unsigned long do_brk(unsigned long addr, unsigned long len) vma->vm_flags = flags; vma->vm_page_prot = vm_get_page_prot(flags); vma_link(mm, vma, prev, rb_link, rb_parent); + ksm_vma_add_new(vma); out: perf_event_mmap(vma); mm->total_vm += len >> PAGE_SHIFT; @@ -2887,6 +2902,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, new_vma->vm_ops->open(new_vma); vma_link(mm, new_vma, prev, rb_link, rb_parent); *need_rmap_locks = false; + ksm_vma_add_new(new_vma); } } return new_vma; @@ -3004,6 +3020,7 @@ static struct vm_area_struct *__install_special_mapping( mm->total_vm += len >> PAGE_SHIFT; perf_event_mmap(vma); + ksm_vma_add_new(vma); return vma; -- 2.1.3
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