For the huge orders allowed by writable mmap() faults on tmpfs,
the mTHP interface is used to control the allowable huge orders,
while 'huge_shmem_orders_inherit' maintains backward compatibility
with top-level interface.
For the huge orders allowed by write() and fallocate() paths on tmpfs,
getting a highest order hint based on the size of write and fallocate
paths, then will try each allowable huge orders filtered by the mTHP
interfaces if set.
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
mm/memory.c | 4 ++--
mm/shmem.c | 42 ++++++++++++++++++++++--------------------
2 files changed, 24 insertions(+), 22 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 802d0d8a40f9..3a7f43c66db7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4877,10 +4877,10 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
/*
* Using per-page fault to maintain the uffd semantics, and same
- * approach also applies to non-anonymous-shmem faults to avoid
+ * approach also applies to non shmem/tmpfs faults to avoid
* inflating the RSS of the process.
*/
- if (!vma_is_anon_shmem(vma) || unlikely(userfaultfd_armed(vma))) {
+ if (!vma_is_shmem(vma) || unlikely(userfaultfd_armed(vma))) {
nr_pages = 1;
} else if (nr_pages > 1) {
pgoff_t idx = folio_page_idx(folio, page);
diff --git a/mm/shmem.c b/mm/shmem.c
index cc0c1b790267..8e60cc566196 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1692,26 +1692,6 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED))
return 0;
- global_huge = shmem_huge_global_enabled(inode, index, shmem_huge_force,
- vma, vm_flags);
- if (!vma || !vma_is_anon_shmem(vma)) {
- /*
- * For tmpfs, if top level huge page is enabled, we just allow
- * PMD size THP to keep interface backward compatibility.
- */
- if (global_huge)
- return BIT(HPAGE_PMD_ORDER);
-
- /*
- * Otherwise, get a highest order hint based on the size of
- * write and fallocate paths, then will try each allowable
- * huge orders.
- */
- order = shmem_mapping_size_order(inode->i_mapping, index,
- len, SHMEM_SB(inode->i_sb));
- return BIT(order + 1) - 1;
- }
-
/*
* Following the 'deny' semantics of the top level, force the huge
* option off from all mounts.
@@ -1742,9 +1722,31 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
if (vm_flags & VM_HUGEPAGE)
mask |= READ_ONCE(huge_shmem_orders_madvise);
+ global_huge = shmem_huge_global_enabled(inode, index, shmem_huge_force,
+ vma, vm_flags);
if (global_huge)
mask |= READ_ONCE(huge_shmem_orders_inherit);
+ /*
+ * For the huge orders allowed by writable mmap() faults on tmpfs,
+ * the mTHP interface is used to control the allowable huge orders,
+ * while 'huge_shmem_orders_inherit' maintains backward compatibility
+ * with top-level interface.
+ *
+ * For the huge orders allowed by write() and fallocate() paths on tmpfs,
+ * get a highest order hint based on the size of write and fallocate
+ * paths, then will try each allowable huge orders filtered by the mTHP
+ * interfaces if set.
+ */
+ if (!vma && !global_huge) {
+ int highest_order = shmem_mapping_size_order(inode->i_mapping, index, len,
+ SHMEM_SB(inode->i_sb));
+
+ if (!mask)
+ return highest_order > 0 ? BIT(highest_order + 1) - 1 : 0;
+
+ mask &= BIT(highest_order + 1) - 1;
+ }
return orders & mask;
}
--
2.39.3
