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authorFrederic Weisbecker2009-10-18 01:09:09 +0200
committerFrederic Weisbecker2009-10-18 01:12:33 +0200
commit0f8f86c7bdd1c954fbe153af437a0d91a6c5721a (patch)
tree94a8d419a470a4f9852ca397bb9bbe48db92ff5c /mm/mremap.c
parentMerge branch 'linus' into tracing/hw-breakpoints (diff)
parentperf tools: Move dereference after NULL test (diff)
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Merge commit 'perf/core' into perf/hw-breakpoint
Conflicts: kernel/Makefile kernel/trace/Makefile kernel/trace/trace.h samples/Makefile Merge reason: We need to be uptodate with the perf events development branch because we plan to rewrite the breakpoints API on top of perf events.
Diffstat (limited to 'mm/mremap.c')
-rw-r--r--mm/mremap.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index a39b7b91be46..97bff2547719 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -11,6 +11,7 @@
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/shm.h>
+#include <linux/ksm.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/capability.h>
@@ -85,8 +86,8 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
if (vma->vm_file) {
/*
* Subtle point from Rajesh Venkatasubramanian: before
- * moving file-based ptes, we must lock vmtruncate out,
- * since it might clean the dst vma before the src vma,
+ * moving file-based ptes, we must lock truncate_pagecache
+ * out, since it might clean the dst vma before the src vma,
* and we propagate stale pages into the dst afterward.
*/
mapping = vma->vm_file->f_mapping;
@@ -174,6 +175,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
unsigned long excess = 0;
unsigned long hiwater_vm;
int split = 0;
+ int err;
/*
* We'd prefer to avoid failure later on in do_munmap:
@@ -182,6 +184,18 @@ static unsigned long move_vma(struct vm_area_struct *vma,
if (mm->map_count >= sysctl_max_map_count - 3)
return -ENOMEM;
+ /*
+ * Advise KSM to break any KSM pages in the area to be moved:
+ * it would be confusing if they were to turn up at the new
+ * location, where they happen to coincide with different KSM
+ * pages recently unmapped. But leave vma->vm_flags as it was,
+ * so KSM can come around to merge on vma and new_vma afterwards.
+ */
+ err = ksm_madvise(vma, old_addr, old_addr + old_len,
+ MADV_UNMERGEABLE, &vm_flags);
+ if (err)
+ return err;
+
new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff);
if (!new_vma)