The patch titled
Subject: thp, s390: disable thp for kvm host on s390
has been added to the -mm tree. Its filename is
thp-s390-disable-thp-for-kvm-host-on-s390.patch
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------------------------------------------------------
From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Subject: thp, s390: disable thp for kvm host on s390
This patch is part of the architecture backend for thp on s390. It
disables thp for kvm hosts, because there is no kvm host hugepage support
so far. Existing thp mappings are split by follow_page() with FOLL_SPLIT,
and future thp mappings are prevented by setting VM_NOHUGEPAGE in
mm->def_flags.
Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Hillf Danton <dhillf@xxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/pgtable.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff -puN arch/s390/mm/pgtable.c~thp-s390-disable-thp-for-kvm-host-on-s390 arch/s390/mm/pgtable.c
--- a/arch/s390/mm/pgtable.c~thp-s390-disable-thp-for-kvm-host-on-s390
+++ a/arch/s390/mm/pgtable.c
@@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather
tlb_table_flush(tlb);
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void thp_split_vma(struct vm_area_struct *vma)
+{
+ unsigned long addr;
+ struct page *page;
+
+ for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) {
+ page = follow_page(vma, addr, FOLL_SPLIT);
+ }
+}
+
+void thp_split_mm(struct mm_struct *mm)
+{
+ struct vm_area_struct *vma = mm->mmap;
+
+ while (vma != NULL) {
+ thp_split_vma(vma);
+ vma->vm_flags &= ~VM_HUGEPAGE;
+ vma->vm_flags |= VM_NOHUGEPAGE;
+ vma = vma->vm_next;
+ }
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
/*
* switch on pgstes for its userspace process (for kvm)
*/
@@ -824,6 +848,12 @@ int s390_enable_sie(void)
if (!mm)
return -ENOMEM;
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ /* split thp mappings and disable thp for future mappings */
+ thp_split_mm(mm);
+ mm->def_flags |= VM_NOHUGEPAGE;
+#endif
+
/* Now lets check again if something happened */
task_lock(tsk);
if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
_
Patches currently in -mm which might be from gerald.schaefer@xxxxxxxxxx are
linux-next.patch
thp-remove-assumptions-on-pgtable_t-type.patch
thp-introduce-pmdp_invalidate.patch
thp-make-madv_hugepage-check-for-mm-def_flags.patch
thp-s390-thp-splitting-backend-for-s390.patch
thp-s390-thp-pagetable-pre-allocation-for-s390.patch
thp-s390-disable-thp-for-kvm-host-on-s390.patch
thp-s390-architecture-backend-for-thp-on-s390.patch
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