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authorJérôme Glisse <jglisse@redhat.com>2017-11-16 04:34:11 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-16 05:21:03 +0300
commit4645b9fe84bf4878f04c7959a75df7c3c2d1bbb9 (patch)
tree83fc19e23f907ea229fd8a99aedbbf967057eae4 /include
parent0f10851ea475e08896ee5d9a2036d1bb46a8f3a4 (diff)
downloadlinux-4645b9fe84bf4878f04c7959a75df7c3c2d1bbb9.tar.xz
mm/mmu_notifier: avoid call to invalidate_range() in range_end()
This is an optimization patch that only affect mmu_notifier users which rely on the invalidate_range() callback. This patch avoids calling that callback twice in a row from inside __mmu_notifier_invalidate_range_end Existing pattern (before this patch): mmu_notifier_invalidate_range_start() pte/pmd/pud_clear_flush_notify() mmu_notifier_invalidate_range() mmu_notifier_invalidate_range_end() mmu_notifier_invalidate_range() New pattern (after this patch): mmu_notifier_invalidate_range_start() pte/pmd/pud_clear_flush_notify() mmu_notifier_invalidate_range() mmu_notifier_invalidate_range_only_end() We call the invalidate_range callback after clearing the page table under the page table lock and we skip the call to invalidate_range inside the __mmu_notifier_invalidate_range_end() function. Idea from Andrea Arcangeli Link: http://lkml.kernel.org/r/20171017031003.7481-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Alistair Popple <alistair@popple.id.au> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mmu_notifier.h17
1 files changed, 15 insertions, 2 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 130831718e95..b25dc9db19fc 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -214,7 +214,8 @@ extern void __mmu_notifier_change_pte(struct mm_struct *mm,
extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
unsigned long start, unsigned long end);
extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
- unsigned long start, unsigned long end);
+ unsigned long start, unsigned long end,
+ bool only_end);
extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
unsigned long start, unsigned long end);
@@ -268,7 +269,14 @@ static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
unsigned long start, unsigned long end)
{
if (mm_has_notifiers(mm))
- __mmu_notifier_invalidate_range_end(mm, start, end);
+ __mmu_notifier_invalidate_range_end(mm, start, end, false);
+}
+
+static inline void mmu_notifier_invalidate_range_only_end(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ if (mm_has_notifiers(mm))
+ __mmu_notifier_invalidate_range_end(mm, start, end, true);
}
static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
@@ -439,6 +447,11 @@ static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
{
}
+static inline void mmu_notifier_invalidate_range_only_end(struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+}
+
static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
unsigned long start, unsigned long end)
{