summaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>2021-02-24 23:07:32 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-25 00:38:32 +0300
commitbae84953815793f68ddd8edeadd3f4e32676a2c8 (patch)
tree4c0db420f34b1a9fef94801d73bc33bc48bdb659 /include
parent2efeb8da992b955fa7705259e4b2f5937979deff (diff)
downloadlinux-bae84953815793f68ddd8edeadd3f4e32676a2c8.tar.xz
mm/pmem: avoid inserting hugepage PTE entry with fsdax if hugepage support is disabled
Differentiate between hardware not supporting hugepages and user disabling THP via 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' For the devdax namespace, the kernel handles the above via the supported_alignment attribute and failing to initialize the namespace if the namespace align value is not supported on the platform. For the fsdax namespace, the kernel will continue to initialize the namespace. This can result in the kernel creating a huge pte entry even though the hardware don't support the same. We do want hugepage support with pmem even if the end-user disabled THP via sysfs file (/sys/kernel/mm/transparent_hugepage/enabled). Hence differentiate between hardware/firmware lacking support vs user-controlled disable of THP and prevent a huge fault if the hardware lacks hugepage support. Link: https://lkml.kernel.org/r/20210205023956.417587-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/huge_mm.h15
1 files changed, 9 insertions, 6 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 6a19f35f836b..ba973efcd369 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -78,6 +78,7 @@ 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_FLAG,
TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
@@ -123,6 +124,13 @@ extern unsigned long transparent_hugepage_flags;
*/
static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
{
+
+ /*
+ * If the hardware/firmware marked hugepage support disabled.
+ */
+ if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
+ return false;
+
if (vma->vm_flags & VM_NOHUGEPAGE)
return false;
@@ -134,12 +142,7 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG))
return true;
- /*
- * For dax vmas, try to always use hugepage mappings. If the kernel does
- * not support hugepages, fsdax mappings will fallback to PAGE_SIZE
- * mappings, and device-dax namespaces, that try to guarantee a given
- * mapping size, will fail to enable
- */
+
if (vma_is_dax(vma))
return true;