sparc64: Reduce TLB flushes during hugepte changes
During hugepage map/unmap, TSB and TLB flushes are currently
issued at every PAGE_SIZE'd boundary which is unnecessary.
We now issue the flush at REAL_HPAGE_SIZE boundaries only.
Without this patch workloads which unmap a large hugepage
backed VMA region get CPU lockups due to excessive TLB
flush calls.
Orabug: 22365539, 22643230, 22995196
Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index 4977800..ba52e64 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -176,17 +176,31 @@
pte_t *ptep, pte_t entry)
{
int i;
+ pte_t orig[2];
+ unsigned long nptes;
if (!pte_present(*ptep) && pte_present(entry))
mm->context.huge_pte_count++;
addr &= HPAGE_MASK;
- for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
- set_pte_at(mm, addr, ptep, entry);
+
+ nptes = 1 << HUGETLB_PAGE_ORDER;
+ orig[0] = *ptep;
+ orig[1] = *(ptep + nptes / 2);
+ for (i = 0; i < nptes; i++) {
+ *ptep = entry;
ptep++;
addr += PAGE_SIZE;
pte_val(entry) += PAGE_SIZE;
}
+
+ /* Issue TLB flush at REAL_HPAGE_SIZE boundaries */
+ addr -= REAL_HPAGE_SIZE;
+ ptep -= nptes / 2;
+ maybe_tlb_batch_add(mm, addr, ptep, orig[1], 0);
+ addr -= REAL_HPAGE_SIZE;
+ ptep -= nptes / 2;
+ maybe_tlb_batch_add(mm, addr, ptep, orig[0], 0);
}
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
@@ -194,19 +208,28 @@
{
pte_t entry;
int i;
+ unsigned long nptes;
entry = *ptep;
if (pte_present(entry))
mm->context.huge_pte_count--;
addr &= HPAGE_MASK;
-
- for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
- pte_clear(mm, addr, ptep);
+ nptes = 1 << HUGETLB_PAGE_ORDER;
+ for (i = 0; i < nptes; i++) {
+ *ptep = __pte(0UL);
addr += PAGE_SIZE;
ptep++;
}
+ /* Issue TLB flush at REAL_HPAGE_SIZE boundaries */
+ addr -= REAL_HPAGE_SIZE;
+ ptep -= nptes / 2;
+ maybe_tlb_batch_add(mm, addr, ptep, entry, 0);
+ addr -= REAL_HPAGE_SIZE;
+ ptep -= nptes / 2;
+ maybe_tlb_batch_add(mm, addr, ptep, entry, 0);
+
return entry;
}