Bring back the direct map optimization when PMAP_PREFER isn't defined.

PMAP_PREFER is checked to prevent cache aliasing issues when the physical
page is mapped at different virtual addresses.

This speeds up file-based mmap faults.

ok kettenis@

diff --git a/sys/uvm/uvm_pager.c b/sys/uvm/uvm_pager.c
index 2f886c0..3de05d3 100644 (file)
--- a/sys/uvm/uvm_pager.c
+++ b/sys/uvm/uvm_pager.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_pager.c,v 1.85 2022/07/24 11:00:22 mpi Exp $      */
+/*     $OpenBSD: uvm_pager.c,v 1.86 2022/08/02 14:04:06 mpi Exp $      */
 /*     $NetBSD: uvm_pager.c,v 1.36 2000/11/27 18:26:41 chs Exp $       */
 
 /*
@@ -258,6 +258,15 @@ uvm_pagermapin(struct vm_page **pps, int npages, int flags)
        vsize_t size;
        struct vm_page *pp;
 
+#if defined(__HAVE_PMAP_DIRECT) && !defined(PMAP_PREFER)
+       /* use direct mappings for single page */
+       if (npages == 1) {
+               KASSERT(pps[0]);
+               KASSERT(pps[0]->pg_flags & PG_BUSY);
+               return pmap_map_direct(pps[0]);
+       }
+#endif
+
        prot = PROT_READ;
        if (flags & UVMPAGER_MAPIN_READ)
                prot |= PROT_WRITE;
@@ -294,6 +303,13 @@ uvm_pagermapin(struct vm_page **pps, int npages, int flags)
 void
 uvm_pagermapout(vaddr_t kva, int npages)
 {
+#if defined(__HAVE_PMAP_DIRECT) && !defined(PMAP_PREFER)
+       /* use direct mappings for single page */
+       if (npages == 1) {
+               pmap_unmap_direct(kva);
+               return;
+       }
+#endif
 
        pmap_remove(pmap_kernel(), kva, kva + ((vsize_t)npages << PAGE_SHIFT));
        pmap_update(pmap_kernel());