Module Name: src
Committed By: ad
Date: Fri Mar 20 18:50:09 UTC 2020
Modified Files:
src/sys/uvm: uvm_fault.c
Log Message:
uvm_fault_upper_lookup(): don't call pmap_extract() and pmap_update() more
often than needed.
To generate a diff of this commit:
cvs rdiff -u -r1.219 -r1.220 src/sys/uvm/uvm_fault.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/uvm/uvm_fault.c
diff -u src/sys/uvm/uvm_fault.c:1.219 src/sys/uvm/uvm_fault.c:1.220
--- src/sys/uvm/uvm_fault.c:1.219 Tue Mar 17 18:31:39 2020
+++ src/sys/uvm/uvm_fault.c Fri Mar 20 18:50:09 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_fault.c,v 1.219 2020/03/17 18:31:39 ad Exp $ */
+/* $NetBSD: uvm_fault.c,v 1.220 2020/03/20 18:50:09 ad Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_fault.c,v 1.219 2020/03/17 18:31:39 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_fault.c,v 1.220 2020/03/20 18:50:09 ad Exp $");
#include "opt_uvmhist.h"
@@ -1166,6 +1166,7 @@ uvm_fault_upper_lookup(
int lcv;
vaddr_t currva;
bool shadowed __unused;
+ bool entered;
UVMHIST_FUNC("uvm_fault_upper_lookup"); UVMHIST_CALLED(maphist);
/* locked: maps(read), amap(if there) */
@@ -1179,18 +1180,9 @@ uvm_fault_upper_lookup(
currva = flt->startva;
shadowed = false;
+ entered = false;
for (lcv = 0; lcv < flt->npages; lcv++, currva += PAGE_SIZE) {
/*
- * don't play with VAs that are already mapped
- * (except for center)
- */
- if (lcv != flt->centeridx &&
- pmap_extract(ufi->orig_map->pmap, currva, NULL)) {
- pages[lcv] = PGO_DONTCARE;
- continue;
- }
-
- /*
* unmapped or center page. check if any anon at this level.
*/
if (amap == NULL || anons[lcv] == NULL) {
@@ -1213,12 +1205,21 @@ uvm_fault_upper_lookup(
KASSERT(anon->an_lock == amap->am_lock);
- /* Ignore loaned and busy pages. */
- if (pg && pg->loan_count == 0 && (pg->flags & PG_BUSY) == 0) {
+ /*
+ * ignore loaned and busy pages.
+ * don't play with VAs that are already mapped.
+ */
+
+ if (pg && pg->loan_count == 0 && (pg->flags & PG_BUSY) == 0 &&
+ !pmap_extract(ufi->orig_map->pmap, currva, NULL)) {
uvm_fault_upper_neighbor(ufi, flt, currva,
pg, anon->an_ref > 1);
+ entered = true;
}
}
+ if (entered) {
+ pmap_update(ufi->orig_map->pmap);
+ }
/* locked: maps(read), amap(if there) */
KASSERT(amap == NULL || rw_write_held(amap->am_lock));
@@ -1276,8 +1277,6 @@ uvm_fault_upper_neighbor(
readonly ? (flt->enter_prot & ~VM_PROT_WRITE) :
flt->enter_prot,
PMAP_CANFAIL | (flt->wire_mapping ? PMAP_WIRED : 0));
-
- pmap_update(ufi->orig_map->pmap);
}
/*
