The patch titled
Subject: mmu_notifier: add the callback for mmu_notifier_invalidate_range()
has been added to the -mm tree. Its filename is
mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
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------------------------------------------------------
From: Joerg Roedel <jroedel@xxxxxxx>
Subject: mmu_notifier: add the callback for mmu_notifier_invalidate_range()
Now that the mmu_notifier_invalidate_range() calls are in place, add the
callback to allow subsystems to register against it.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reviewed-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Johannes Weiner <jweiner@xxxxxxxxxx>
Cc: Jay Cornwall <Jay.Cornwall@xxxxxxx>
Cc: Oded Gabbay <Oded.Gabbay@xxxxxxx>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmu_notifier.h | 37 ++++++++++++++++++++++++++++-----
mm/mmu_notifier.c | 25 ++++++++++++++++++++++
2 files changed, 57 insertions(+), 5 deletions(-)
diff -puN include/linux/mmu_notifier.h~mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range include/linux/mmu_notifier.h
--- a/include/linux/mmu_notifier.h~mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range
+++ a/include/linux/mmu_notifier.h
@@ -98,11 +98,11 @@ struct mmu_notifier_ops {
/*
* invalidate_range_start() and invalidate_range_end() must be
* paired and are called only when the mmap_sem and/or the
- * locks protecting the reverse maps are held. The subsystem
- * must guarantee that no additional references are taken to
- * the pages in the range established between the call to
- * invalidate_range_start() and the matching call to
- * invalidate_range_end().
+ * locks protecting the reverse maps are held. If the subsystem
+ * can't guarantee that no additional references are taken to
+ * the pages in the range, it has to implement the
+ * invalidate_range() notifier to remove any references taken
+ * after invalidate_range_start().
*
* Invalidation of multiple concurrent ranges may be
* optionally permitted by the driver. Either way the
@@ -144,6 +144,29 @@ struct mmu_notifier_ops {
void (*invalidate_range_end)(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start, unsigned long end);
+
+ /*
+ * invalidate_range() is either called between
+ * invalidate_range_start() and invalidate_range_end() when the
+ * VM has to free pages that where unmapped, but before the
+ * pages are actually freed, or outside of _start()/_end() when
+ * a (remote) TLB is necessary.
+ *
+ * If invalidate_range() is used to manage a non-CPU TLB with
+ * shared page-tables, it not necessary to implement the
+ * invalidate_range_start()/end() notifiers, as
+ * invalidate_range() alread catches the points in time when an
+ * external TLB range needs to be flushed.
+ *
+ * The invalidate_range() function is called under the ptl
+ * spin-lock and not allowed to sleep.
+ *
+ * Note that this function might be called with just a sub-range
+ * of what was passed to invalidate_range_start()/end(), if
+ * called between those functions.
+ */
+ void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm,
+ unsigned long start, unsigned long end);
};
/*
@@ -190,6 +213,8 @@ extern void __mmu_notifier_invalidate_ra
unsigned long start, unsigned long end);
extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
unsigned long start, unsigned long end);
+extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
+ unsigned long start, unsigned long end);
static inline void mmu_notifier_release(struct mm_struct *mm)
{
@@ -245,6 +270,8 @@ static inline void mmu_notifier_invalida
static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
unsigned long start, unsigned long end)
{
+ if (mm_has_notifiers(mm))
+ __mmu_notifier_invalidate_range(mm, start, end);
}
static inline void mmu_notifier_mm_init(struct mm_struct *mm)
diff -puN mm/mmu_notifier.c~mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range mm/mmu_notifier.c
--- a/mm/mmu_notifier.c~mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range
+++ a/mm/mmu_notifier.c
@@ -193,6 +193,16 @@ void __mmu_notifier_invalidate_range_end
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ /*
+ * Call invalidate_range here too to avoid the need for the
+ * subsystem of having to register an invalidate_range_end
+ * call-back when there is invalidate_range already. Usually a
+ * subsystem registers either invalidate_range_start()/end() or
+ * invalidate_range(), so this will be no additional overhead
+ * (besides the pointer check).
+ */
+ if (mn->ops->invalidate_range)
+ mn->ops->invalidate_range(mn, mm, start, end);
if (mn->ops->invalidate_range_end)
mn->ops->invalidate_range_end(mn, mm, start, end);
}
@@ -200,6 +210,21 @@ void __mmu_notifier_invalidate_range_end
}
EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range_end);
+void __mmu_notifier_invalidate_range(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct mmu_notifier *mn;
+ int id;
+
+ id = srcu_read_lock(&srcu);
+ hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
+ if (mn->ops->invalidate_range)
+ mn->ops->invalidate_range(mn, mm, start, end);
+ }
+ srcu_read_unlock(&srcu, id);
+}
+EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range);
+
static int do_mmu_notifier_register(struct mmu_notifier *mn,
struct mm_struct *mm,
int take_mmap_sem)
_
Patches currently in -mm which might be from jroedel@xxxxxxx are
mmu_notifier-add-mmu_notifier_invalidate_range.patch
mmu_notifier-call-mmu_notifier_invalidate_range-from-vmm.patch
mmu_notifier-add-the-call-back-for-mmu_notifier_invalidate_range.patch
linux-next.patch
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