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sparc64: Reduce TLB flushes during hugepte changes

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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>
This commit is contained in:
Nitin Gupta
2016-03-30 11:17:13 -07:00
committed by David S. Miller
parent b1ac6b7b40
commit 24e49ee3d7
6 changed files with 97 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
arch/sparc/mm/hugetlbpage.c
View File

@@ -176,17 +176,31 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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 huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
{
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;
}