Module Name: src
Committed By: bouyer
Date: Mon Feb 20 19:14:24 UTC 2012
Modified Files:
src/sys/uvm: uvm_km.c uvm_kmguard.c uvm_map.c
Log Message:
When using uvm_km_pgremove_intrsafe() make sure mappings are removed
before returning the pages to the free pool. Otherwise, under Xen,
a page which still has a writable mapping could be allocated for
a PDP by another CPU and the hypervisor would refuse it (this is
PR port-xen/45975).
For this, move the pmap_kremove() calls inside uvm_km_pgremove_intrsafe(),
and do pmap_kremove()/uvm_pagefree() in batch of (at most) 16 entries
(as suggested by Chuck Silvers on tech-kern@, see also
http://mail-index.netbsd.org/tech-kern/2012/02/17/msg012727.html and
followups).
To generate a diff of this commit:
cvs rdiff -u -r1.121 -r1.122 src/sys/uvm/uvm_km.c
cvs rdiff -u -r1.9 -r1.10 src/sys/uvm/uvm_kmguard.c
cvs rdiff -u -r1.314 -r1.315 src/sys/uvm/uvm_map.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_km.c
diff -u src/sys/uvm/uvm_km.c:1.121 src/sys/uvm/uvm_km.c:1.122
--- src/sys/uvm/uvm_km.c:1.121 Sun Feb 19 00:05:56 2012
+++ src/sys/uvm/uvm_km.c Mon Feb 20 19:14:23 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_km.c,v 1.121 2012/02/19 00:05:56 rmind Exp $ */
+/* $NetBSD: uvm_km.c,v 1.122 2012/02/20 19:14:23 bouyer Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -120,7 +120,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_km.c,v 1.121 2012/02/19 00:05:56 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_km.c,v 1.122 2012/02/20 19:14:23 bouyer Exp $");
#include "opt_uvmhist.h"
@@ -459,8 +459,12 @@ uvm_km_pgremove(vaddr_t startva, vaddr_t
void
uvm_km_pgremove_intrsafe(struct vm_map *map, vaddr_t start, vaddr_t end)
{
+#define __PGRM_BATCH 16
struct vm_page *pg;
- paddr_t pa;
+ paddr_t pa[__PGRM_BATCH];
+ int npgrm, i;
+ vaddr_t va, batch_vastart;
+
UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
KASSERT(VM_MAP_IS_KERNEL(map));
@@ -468,16 +472,30 @@ uvm_km_pgremove_intrsafe(struct vm_map *
KASSERT(start < end);
KASSERT(end <= vm_map_max(map));
- for (; start < end; start += PAGE_SIZE) {
- if (!pmap_extract(pmap_kernel(), start, &pa)) {
- continue;
+ for (va = start; va < end;) {
+ batch_vastart = va;
+ /* create a batch of at most __PGRM_BATCH pages to free */
+ for (i = 0;
+ i < __PGRM_BATCH && va < end;
+ va += PAGE_SIZE) {
+ if (!pmap_extract(pmap_kernel(), va, &pa[i])) {
+ continue;
+ }
+ i++;
+ }
+ npgrm = i;
+ /* now remove the mappings */
+ pmap_kremove(batch_vastart, PAGE_SIZE * npgrm);
+ /* and free the pages */
+ for (i = 0; i < npgrm; i++) {
+ pg = PHYS_TO_VM_PAGE(pa[i]);
+ KASSERT(pg);
+ KASSERT(pg->uobject == NULL && pg->uanon == NULL);
+ KASSERT((pg->flags & PG_BUSY) == 0);
+ uvm_pagefree(pg);
}
- pg = PHYS_TO_VM_PAGE(pa);
- KASSERT(pg);
- KASSERT(pg->uobject == NULL && pg->uanon == NULL);
- KASSERT((pg->flags & PG_BUSY) == 0);
- uvm_pagefree(pg);
}
+#undef __PGRM_BATCH
}
#if defined(DEBUG)
@@ -668,7 +686,6 @@ uvm_km_free(struct vm_map *map, vaddr_t
* remove it after. See comment below about KVA visibility.
*/
uvm_km_pgremove_intrsafe(map, addr, addr + size);
- pmap_kremove(addr, size);
}
/*
@@ -745,7 +762,6 @@ again:
} else {
uvm_km_pgremove_intrsafe(kernel_map, va,
va + size);
- pmap_kremove(va, size);
vmem_free(kmem_va_arena, va, size);
return ENOMEM;
}
@@ -781,7 +797,6 @@ uvm_km_kmem_free(vmem_t *vm, vmem_addr_t
}
#endif /* PMAP_UNMAP_POOLPAGE */
uvm_km_pgremove_intrsafe(kernel_map, addr, addr + size);
- pmap_kremove(addr, size);
pmap_update(pmap_kernel());
vmem_free(vm, addr, size);
Index: src/sys/uvm/uvm_kmguard.c
diff -u src/sys/uvm/uvm_kmguard.c:1.9 src/sys/uvm/uvm_kmguard.c:1.10
--- src/sys/uvm/uvm_kmguard.c:1.9 Sun Feb 5 11:08:06 2012
+++ src/sys/uvm/uvm_kmguard.c Mon Feb 20 19:14:23 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_kmguard.c,v 1.9 2012/02/05 11:08:06 rmind Exp $ */
+/* $NetBSD: uvm_kmguard.c,v 1.10 2012/02/20 19:14:23 bouyer Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@@ -39,7 +39,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_kmguard.c,v 1.9 2012/02/05 11:08:06 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_kmguard.c,v 1.10 2012/02/20 19:14:23 bouyer Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -180,7 +180,6 @@ uvm_kmguard_free(struct uvm_kmguard *kg,
*/
uvm_km_pgremove_intrsafe(kernel_map, va, va + PAGE_SIZE * 2);
- pmap_kremove(va, PAGE_SIZE * 2);
pmap_update(pmap_kernel());
/*
Index: src/sys/uvm/uvm_map.c
diff -u src/sys/uvm/uvm_map.c:1.314 src/sys/uvm/uvm_map.c:1.315
--- src/sys/uvm/uvm_map.c:1.314 Sun Feb 19 00:05:56 2012
+++ src/sys/uvm/uvm_map.c Mon Feb 20 19:14:23 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_map.c,v 1.314 2012/02/19 00:05:56 rmind Exp $ */
+/* $NetBSD: uvm_map.c,v 1.315 2012/02/20 19:14:23 bouyer Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.314 2012/02/19 00:05:56 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.315 2012/02/20 19:14:23 bouyer Exp $");
#include "opt_ddb.h"
#include "opt_uvmhist.h"
@@ -2221,7 +2221,6 @@ uvm_unmap_remove(struct vm_map *map, vad
if ((entry->flags & UVM_MAP_KMAPENT) == 0) {
uvm_km_pgremove_intrsafe(map, entry->start,
entry->end);
- pmap_kremove(entry->start, len);
}
} else if (UVM_ET_ISOBJ(entry) &&
UVM_OBJ_IS_KERN_OBJECT(entry->object.uvm_obj)) {
