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authorJason Gunthorpe <jgg@mellanox.com>2018-08-16 13:08:18 -0600
committerJason Gunthorpe <jgg@mellanox.com>2018-08-16 13:12:00 -0600
commit89982f7ccee2fcd8fea7936b81eec6defbf0f131 (patch)
treefc553c8d008d24595ad7de0ea0f3b56f656da27c /mm/rmap.c
parenta1ceeca679dccc492235f0f629d9e9f7b3d51ca8 (diff)
parent94710cac0ef4ee177a63b5227664b38c95bbf703 (diff)
downloadlwn-89982f7ccee2fcd8fea7936b81eec6defbf0f131.tar.gz
lwn-89982f7ccee2fcd8fea7936b81eec6defbf0f131.zip
Merge tag 'v4.18' into rdma.git for-next
Resolve merge conflicts from the -rc cycle against the rdma.git tree: Conflicts: drivers/infiniband/core/uverbs_cmd.c - New ifs added to ib_uverbs_ex_create_flow in -rc and for-next - Merge removal of file->ucontext in for-next with new code in -rc drivers/infiniband/core/uverbs_main.c - for-next removed code from ib_uverbs_write() that was modified in for-rc Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 6db729dc4c50..eb477809a5c0 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -64,6 +64,7 @@
#include <linux/backing-dev.h>
#include <linux/page_idle.h>
#include <linux/memremap.h>
+#include <linux/userfaultfd_k.h>
#include <asm/tlbflush.h>
@@ -1481,11 +1482,16 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
set_pte_at(mm, address, pvmw.pte, pteval);
}
- } else if (pte_unused(pteval)) {
+ } else if (pte_unused(pteval) && !userfaultfd_armed(vma)) {
/*
* The guest indicated that the page content is of no
* interest anymore. Simply discard the pte, vmscan
* will take care of the rest.
+ * A future reference will then fault in a new zero
+ * page. When userfaultfd is active, we must not drop
+ * this page though, as its main user (postcopy
+ * migration) will not expect userfaults on already
+ * copied pages.
*/
dec_mm_counter(mm, mm_counter(page));
/* We have to invalidate as we cleared the pte */