From a913e182ab9484308e870af37a14d372742d53b0 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 21 Sep 2009 17:02:26 -0700 Subject: 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 Acked-by: Izik Eidus Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/ksm.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'mm/ksm.c') diff --git a/mm/ksm.c b/mm/ksm.c index 3bd54ce9eb38..e11e7a5ac84f 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -32,7 +32,6 @@ #include #include -#include #include /* @@ -284,6 +283,19 @@ static inline int in_stable_tree(struct rmap_item *rmap_item) return rmap_item->address & STABLE_FLAG; } +/* + * ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's + * page tables after it has passed through ksm_exit() - which, if necessary, + * takes mmap_sem briefly to serialize against them. ksm_exit() does not set + * a special flag: they can just back out as soon as mm_users goes to zero. + * ksm_test_exit() is used throughout to make this test for exit: in some + * places for correctness, in some places just to avoid unnecessary work. + */ +static inline bool ksm_test_exit(struct mm_struct *mm) +{ + return atomic_read(&mm->mm_users) == 0; +} + /* * We use break_ksm to break COW on a ksm page: it's a stripped down * -- cgit v1.2.3