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authorJérôme Glisse <jglisse@redhat.com>2019-05-13 17:20:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 09:47:48 -0700
commit023a019a9b4e90b9df8ed5be591787b5c914d74f (patch)
treea260046891a360a35f046429d44199ff5e676886 /mm
parenta3e0d41c2b1f86b483b202d642140d8b86d677ca (diff)
mm/hmm: add default fault flags to avoid the need to pre-fill pfns arrays
The HMM mirror API can be use in two fashions. The first one where the HMM user coalesce multiple page faults into one request and set flags per pfns for of those faults. The second one where the HMM user want to pre-fault a range with specific flags. For the latter one it is a waste to have the user pre-fill the pfn arrays with a default flags value. This patch adds a default flags value allowing user to set them for a range without having to pre-fill the pfn array. Link: http://lkml.kernel.org/r/20190403193318.16478-8-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hmm.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index 3e07f32b94f8..0e21d3594ab6 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -419,6 +419,18 @@ static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
if (!hmm_vma_walk->fault)
return;
+ /*
+ * So we not only consider the individual per page request we also
+ * consider the default flags requested for the range. The API can
+ * be use in 2 fashions. The first one where the HMM user coalesce
+ * multiple page fault into one request and set flags per pfns for
+ * of those faults. The second one where the HMM user want to pre-
+ * fault a range with specific flags. For the latter one it is a
+ * waste to have the user pre-fill the pfn arrays with a default
+ * flags value.
+ */
+ pfns = (pfns & range->pfn_flags_mask) | range->default_flags;
+
/* We aren't ask to do anything ... */
if (!(pfns & range->flags[HMM_PFN_VALID]))
return;