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authorGerald Schaefer <gerald.schaefer@de.ibm.com>2012-10-08 16:30:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:30 +0900
commit274023da1e8a49efa6fd9bf857f8557e5db44cdf (patch)
tree0e741e23da15593646404f06f202c22e497b1ec4 /arch/s390
parent9501d09fa3c4ca18971083dfb0c9aa1afc85f19c (diff)
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@de.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/mm/pgtable.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 1ca371a06516..e86a523875eb 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
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 ||