[3/3] mm/migrate: add stable check in migrate_vma_insert_page()
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Message ID 20200107211208.24595-4-rcampbell@nvidia.com
State New
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Series
  • mm/migrate: add missing check for stable
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Commit Message

Ralph Campbell Jan. 7, 2020, 9:12 p.m. UTC
migrate_vma_insert_page() closely follows the code in:
  __handle_mm_fault()
    handle_pte_fault()
      do_anonymous_page()

Add a call to check_stable_address_space() after locking the page table
entry before inserting a ZONE_DEVICE private zero page mapping similar to
page faulting a new anonymous page.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
---
 mm/migrate.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Comments

Christoph Hellwig Jan. 8, 2020, 7:12 a.m. UTC | #1
On Tue, Jan 07, 2020 at 01:12:08PM -0800, Ralph Campbell wrote:
> migrate_vma_insert_page() closely follows the code in:
>   __handle_mm_fault()
>     handle_pte_fault()
>       do_anonymous_page()

I wonder if we could share more code there?

Otherwise this looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Patch
diff mbox series

diff --git a/mm/migrate.c b/mm/migrate.c
index 4b1a6d69afb5..403b82472d24 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -48,6 +48,7 @@ 
 #include <linux/page_owner.h>
 #include <linux/sched/mm.h>
 #include <linux/ptrace.h>
+#include <linux/oom.h>
 
 #include <asm/tlbflush.h>
 
@@ -2675,6 +2676,14 @@  int migrate_vma_setup(struct migrate_vma *args)
 }
 EXPORT_SYMBOL(migrate_vma_setup);
 
+/*
+ * This code closely matches the code in:
+ *   __handle_mm_fault()
+ *     handle_pte_fault()
+ *       do_anonymous_page()
+ * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
+ * private page.
+ */
 static void migrate_vma_insert_page(struct migrate_vma *migrate,
 				    unsigned long addr,
 				    struct page *page,
@@ -2755,6 +2764,9 @@  static void migrate_vma_insert_page(struct migrate_vma *migrate,
 
 	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 
+	if (check_stable_address_space(mm))
+		goto unlock_abort;
+
 	if (pte_present(*ptep)) {
 		unsigned long pfn = pte_pfn(*ptep);