Commit 274023da authored by Gerald Schaefer's avatar Gerald Schaefer Committed by Linus Torvalds

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: default avatarGerald 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9501d09f
...@@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table) ...@@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
tlb_table_flush(tlb); 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) * switch on pgstes for its userspace process (for kvm)
*/ */
...@@ -824,6 +848,12 @@ int s390_enable_sie(void) ...@@ -824,6 +848,12 @@ int s390_enable_sie(void)
if (!mm) if (!mm)
return -ENOMEM; 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 */ /* Now lets check again if something happened */
task_lock(tsk); task_lock(tsk);
if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
......
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