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ksm: clean up obsolete references
A few cleanups, given the munlock fix: the comment on ksm_test_exit() no longer applies, and it can be made private to ksm.c; there's no more reference to mmu_gather or tlb.h, and mmap.c doesn't need ksm.h. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Izik Eidus <ieidus@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -12,8 +12,6 @@
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#include <linux/sched.h>
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#include <linux/vmstat.h>
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struct mmu_gather;
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#ifdef CONFIG_KSM
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int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
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unsigned long end, int advice, unsigned long *vm_flags);
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@ -27,19 +25,6 @@ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
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return 0;
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}
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/*
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* For KSM to handle OOM without deadlock when it's breaking COW in a
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* likely victim of the OOM killer, exit_mmap() has to serialize with
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* ksm_exit() after freeing mm's pages but before freeing its page tables.
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* That leaves a window in which KSM might refault pages which have just
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* been finally unmapped: guard against that with ksm_test_exit(), and
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* use it after getting mmap_sem in ksm.c, to check if mm is exiting.
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*/
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static inline bool ksm_test_exit(struct mm_struct *mm)
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{
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return atomic_read(&mm->mm_users) == 0;
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}
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static inline void ksm_exit(struct mm_struct *mm)
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{
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if (test_bit(MMF_VM_MERGEABLE, &mm->flags))
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@ -79,11 +64,6 @@ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
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return 0;
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}
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static inline bool ksm_test_exit(struct mm_struct *mm)
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{
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return 0;
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}
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static inline void ksm_exit(struct mm_struct *mm)
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{
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}
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14
mm/ksm.c
14
mm/ksm.c
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@ -32,7 +32,6 @@
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#include <linux/mmu_notifier.h>
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#include <linux/ksm.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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/*
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@ -284,6 +283,19 @@ static inline int in_stable_tree(struct rmap_item *rmap_item)
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return rmap_item->address & STABLE_FLAG;
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}
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/*
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* ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's
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* page tables after it has passed through ksm_exit() - which, if necessary,
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* takes mmap_sem briefly to serialize against them. ksm_exit() does not set
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* a special flag: they can just back out as soon as mm_users goes to zero.
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* ksm_test_exit() is used throughout to make this test for exit: in some
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* places for correctness, in some places just to avoid unnecessary work.
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*/
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static inline bool ksm_test_exit(struct mm_struct *mm)
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{
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return atomic_read(&mm->mm_users) == 0;
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}
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/*
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* We use break_ksm to break COW on a ksm page: it's a stripped down
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*
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