---

yaml --- r: 164422 b: refs/heads/master c: a913e18 h: refs/heads/master v: v3
git-mirror · Sep 22, 2009 · ceb1c62 · ceb1c62
1 parent cafccca
commit ceb1c62
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Showing 4 changed files with 14 additions and 23 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8314c4f24a0a5c9b1f7544e9fa83a1d5367ddaa7
+refs/heads/master: a913e182ab9484308e870af37a14d372742d53b0
diff --git a/trunk/include/linux/ksm.h b/trunk/include/linux/ksm.h
@@ -12,8 +12,6 @@
 #include <linux/sched.h>
 #include <linux/vmstat.h>
 
-struct mmu_gather;
-
 #ifdef CONFIG_KSM
 int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
 		unsigned long end, int advice, unsigned long *vm_flags);
@@ -27,19 +25,6 @@ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
 	return 0;
 }
 
-/*
- * For KSM to handle OOM without deadlock when it's breaking COW in a
- * likely victim of the OOM killer, exit_mmap() has to serialize with
- * ksm_exit() after freeing mm's pages but before freeing its page tables.
- * That leaves a window in which KSM might refault pages which have just
- * been finally unmapped: guard against that with ksm_test_exit(), and
- * use it after getting mmap_sem in ksm.c, to check if mm is exiting.
- */
-static inline bool ksm_test_exit(struct mm_struct *mm)
-{
-	return atomic_read(&mm->mm_users) == 0;
-}
-
 static inline void ksm_exit(struct mm_struct *mm)
 {
 	if (test_bit(MMF_VM_MERGEABLE, &mm->flags))
@@ -79,11 +64,6 @@ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
 	return 0;
 }
 
-static inline bool ksm_test_exit(struct mm_struct *mm)
-{
-	return 0;
-}
-
 static inline void ksm_exit(struct mm_struct *mm)
 {
 }

diff --git a/trunk/mm/ksm.c b/trunk/mm/ksm.c
@@ -32,7 +32,6 @@
 #include <linux/mmu_notifier.h>
 #include <linux/ksm.h>
 
-#include <asm/tlb.h>
 #include <asm/tlbflush.h>
 
 /*
@@ -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
  *

diff --git a/trunk/mm/mmap.c b/trunk/mm/mmap.c
@@ -27,7 +27,6 @@
 #include <linux/mount.h>
 #include <linux/mempolicy.h>
 #include <linux/rmap.h>
-#include <linux/ksm.h>
 #include <linux/mmu_notifier.h>
 #include <linux/perf_event.h>