The patch titled
ksm: first tidy up madvise_vma()
has been added to the -mm tree. Its filename is
ksm-first-tidy-up-madvise_vma.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ksm: first tidy up madvise_vma()
From: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
madvise.c has several levels of switch statements, what to do in which?
Move MADV_DOFORK code down from madvise_vma() to madvise_behavior(), so
madvise_vma() can be a simple router, to madvise_behavior() by default.
vma->vm_flags is an unsigned long so use the same type for new_flags. Add
missing comment lines to describe MADV_DONTFORK and MADV_DOFORK.
Signed-off-by: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxx>
Signed-off-by: Izik Eidus <ieidus@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 39 +++++++++++++--------------------------
1 file changed, 13 insertions(+), 26 deletions(-)
diff -puN mm/madvise.c~ksm-first-tidy-up-madvise_vma mm/madvise.c
--- a/mm/madvise.c~ksm-first-tidy-up-madvise_vma
+++ a/mm/madvise.c
@@ -41,7 +41,7 @@ static long madvise_behavior(struct vm_a
struct mm_struct * mm = vma->vm_mm;
int error = 0;
pgoff_t pgoff;
- int new_flags = vma->vm_flags;
+ unsigned long new_flags = vma->vm_flags;
switch (behavior) {
case MADV_NORMAL:
@@ -57,6 +57,10 @@ static long madvise_behavior(struct vm_a
new_flags |= VM_DONTCOPY;
break;
case MADV_DOFORK:
+ if (vma->vm_flags & VM_IO) {
+ error = -EINVAL;
+ goto out;
+ }
new_flags &= ~VM_DONTCOPY;
break;
}
@@ -211,37 +215,16 @@ static long
madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
unsigned long start, unsigned long end, int behavior)
{
- long error;
-
switch (behavior) {
- case MADV_DOFORK:
- if (vma->vm_flags & VM_IO) {
- error = -EINVAL;
- break;
- }
- case MADV_DONTFORK:
- case MADV_NORMAL:
- case MADV_SEQUENTIAL:
- case MADV_RANDOM:
- error = madvise_behavior(vma, prev, start, end, behavior);
- break;
case MADV_REMOVE:
- error = madvise_remove(vma, prev, start, end);
- break;
-
+ return madvise_remove(vma, prev, start, end);
case MADV_WILLNEED:
- error = madvise_willneed(vma, prev, start, end);
- break;
-
+ return madvise_willneed(vma, prev, start, end);
case MADV_DONTNEED:
- error = madvise_dontneed(vma, prev, start, end);
- break;
-
+ return madvise_dontneed(vma, prev, start, end);
default:
- BUG();
- break;
+ return madvise_behavior(vma, prev, start, end, behavior);
}
- return error;
}
static int
@@ -262,6 +245,7 @@ madvise_behavior_valid(int behavior)
return 0;
}
}
+
/*
* The madvise(2) system call.
*
@@ -286,6 +270,9 @@ madvise_behavior_valid(int behavior)
* so the kernel can free resources associated with it.
* MADV_REMOVE - the application wants to free up the given range of
* pages and associated backing store.
+ * MADV_DONTFORK - omit this area from child's address space when forking:
+ * typically, to avoid COWing pages pinned by get_user_pages().
+ * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
*
* return values:
* zero - success
_
Patches currently in -mm which might be from hugh.dickins@xxxxxxxxxxxxx are
mm-avoid-endless-looping-for-oom-killed-tasks.patch
mm-oom-analysis-add-shmem-vmstat.patch
ksm-add-mmu_notifier-set_pte_at_notify.patch
ksm-first-tidy-up-madvise_vma.patch
ksm-define-madv_mergeable-and-madv_unmergeable.patch
ksm-the-mm-interface-to-ksm.patch
ksm-no-debug-in-page_dup_rmap.patch
ksm-identify-pageksm-pages.patch
ksm-kernel-samepage-merging.patch
ksm-prevent-mremap-move-poisoning.patch
ksm-change-copyright-message.patch
ksm-change-ksm-nice-level-to-be-5.patch
getrusage-fill-ru_maxrss-value.patch
getrusage-fill-ru_maxrss-value-update.patch
ramfs-move-ramfs_magic-to-include-linux-magich.patch
prio_tree-debugging-patch.patch
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