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| author | Jérôme Glisse <jglisse@redhat.com> | 2017-11-16 04:34:11 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-16 05:21:03 +0300 |
| commit | 4645b9fe84bf4878f04c7959a75df7c3c2d1bbb9 (patch) | |
| tree | 83fc19e23f907ea229fd8a99aedbbf967057eae4 /mm/migrate.c | |
| parent | 0f10851ea475e08896ee5d9a2036d1bb46a8f3a4 (diff) | |
| download | linux-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 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 1236449b4777..4d0be47a322a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2089,7 +2089,11 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, set_page_owner_migrate_reason(new_page, MR_NUMA_MISPLACED); spin_unlock(ptl); - mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); + /* + * No need to double call mmu_notifier->invalidate_range() callback as + * the above pmdp_huge_clear_flush_notify() did already call it. + */ + mmu_notifier_invalidate_range_only_end(mm, mmun_start, mmun_end); /* Take an "isolate" reference and put new page on the LRU. */ get_page(new_page); @@ -2805,9 +2809,14 @@ static void migrate_vma_pages(struct migrate_vma *migrate) migrate->src[i] &= ~MIGRATE_PFN_MIGRATE; } + /* + * No need to double call mmu_notifier->invalidate_range() callback as + * the above ptep_clear_flush_notify() inside migrate_vma_insert_page() + * did already call it. + */ if (notified) - mmu_notifier_invalidate_range_end(mm, mmu_start, - migrate->end); + mmu_notifier_invalidate_range_only_end(mm, mmu_start, + migrate->end); } /* |