mm/thp: rename TRANSPARENT_HUGEPAGE_NEVER_DAX to _UNSUPPORTED

TRANSPARENT_HUGEPAGE_NEVER_DAX has nothing to do with DAX.  It's set when
has_transparent_hugepage() returns false, checked in hugepage_vma_check()
and will disable THP completely if false.  Rename it to
TRANSPARENT_HUGEPAGE_UNSUPPORTED to reflect its real purpose.

[peterx@redhat.com: fix comment, per David]
Link: https://lkml.kernel.org/r/ZBMzQW674oHQJV7F@x1n
Link: https://lkml.kernel.org/r/20230315171642.1244625-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 70bd867..9a3a3af 100644 (file)
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -79,7 +79,7 @@ static inline vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn,
 }
 
 enum transparent_hugepage_flag {
-       TRANSPARENT_HUGEPAGE_NEVER_DAX,
+       TRANSPARENT_HUGEPAGE_UNSUPPORTED,
        TRANSPARENT_HUGEPAGE_FLAG,
        TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
        TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 0c1df32..cbf095e 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -88,7 +88,7 @@ bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags,
        /*
         * If the hardware/firmware marked hugepage support disabled.
         */
-       if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
+       if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED))
                return false;
 
        /* khugepaged doesn't collapse DAX vma, but page fault is fine. */
@@ -460,11 +460,7 @@ static int __init hugepage_init(void)
        struct kobject *hugepage_kobj;
 
        if (!has_transparent_hugepage()) {
-               /*
-                * Hardware doesn't support hugepages, hence disable
-                * DAX PMD support.
-                */
-               transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX;
+               transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED;
                return -EINVAL;
        }