Module Name: src
Committed By: riz
Date: Thu Nov 22 20:25:21 UTC 2012
Modified Files:
src/sys/uvm [netbsd-6]: uvm_aobj.c uvm_aobj.h uvm_object.h
Log Message:
Pull up following revision(s) (requested by rmind in ticket #694):
sys/uvm/uvm_aobj.h: revision 1.22
sys/uvm/uvm_aobj.c: revision 1.117
sys/uvm/uvm_aobj.c: revision 1.118
sys/uvm/uvm_aobj.c: revision 1.119
sys/uvm/uvm_object.h: revision 1.33
- Describe uvm_aobj and the lock order.
- Remove unnecessary uao_dropswap_range1() wrapper.
- KNF. Sprinkle some __cacheline_aligned.
- Manage anonymous UVM object reference count with atomic ops.
- Fix an old bug of possible lock against oneself (uao_detach_locked() is
called from uao_swap_off() with uao_list_lock acquired). Also removes
the try-lock dance in uao_swap_off(), since the lock order changes.
To generate a diff of this commit:
cvs rdiff -u -r1.116 -r1.116.8.1 src/sys/uvm/uvm_aobj.c
cvs rdiff -u -r1.21 -r1.21.10.1 src/sys/uvm/uvm_aobj.h
cvs rdiff -u -r1.32 -r1.32.2.1 src/sys/uvm/uvm_object.h
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_aobj.c
diff -u src/sys/uvm/uvm_aobj.c:1.116 src/sys/uvm/uvm_aobj.c:1.116.8.1
--- src/sys/uvm/uvm_aobj.c:1.116 Tue Sep 6 16:41:55 2011
+++ src/sys/uvm/uvm_aobj.c Thu Nov 22 20:25:21 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_aobj.c,v 1.116 2011/09/06 16:41:55 matt Exp $ */
+/* $NetBSD: uvm_aobj.c,v 1.116.8.1 2012/11/22 20:25:21 riz Exp $ */
/*
* Copyright (c) 1998 Chuck Silvers, Charles D. Cranor and
@@ -38,80 +38,69 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_aobj.c,v 1.116 2011/09/06 16:41:55 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_aobj.c,v 1.116.8.1 2012/11/22 20:25:21 riz Exp $");
#include "opt_uvmhist.h"
#include <sys/param.h>
#include <sys/systm.h>
-#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/pool.h>
+#include <sys/atomic.h>
#include <uvm/uvm.h>
/*
- * an aobj manages anonymous-memory backed uvm_objects. in addition
- * to keeping the list of resident pages, it also keeps a list of
- * allocated swap blocks. depending on the size of the aobj this list
- * of allocated swap blocks is either stored in an array (small objects)
- * or in a hash table (large objects).
- */
-
-/*
- * local structures
+ * An anonymous UVM object (aobj) manages anonymous-memory. In addition to
+ * keeping the list of resident pages, it may also keep a list of allocated
+ * swap blocks. Depending on the size of the object, this list is either
+ * stored in an array (small objects) or in a hash table (large objects).
+ *
+ * Lock order
+ *
+ * uao_list_lock ->
+ * uvm_object::vmobjlock
*/
/*
- * for hash tables, we break the address space of the aobj into blocks
- * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to
- * be a power of two.
+ * Note: for hash tables, we break the address space of the aobj into blocks
+ * of UAO_SWHASH_CLUSTER_SIZE pages, which shall be a power of two.
*/
-#define UAO_SWHASH_CLUSTER_SHIFT 4
-#define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT)
+#define UAO_SWHASH_CLUSTER_SHIFT 4
+#define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT)
-/* get the "tag" for this page index */
-#define UAO_SWHASH_ELT_TAG(PAGEIDX) \
- ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT)
+/* Get the "tag" for this page index. */
+#define UAO_SWHASH_ELT_TAG(idx) ((idx) >> UAO_SWHASH_CLUSTER_SHIFT)
+#define UAO_SWHASH_ELT_PAGESLOT_IDX(idx) \
+ ((idx) & (UAO_SWHASH_CLUSTER_SIZE - 1))
-#define UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX) \
- ((PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1))
+/* Given an ELT and a page index, find the swap slot. */
+#define UAO_SWHASH_ELT_PAGESLOT(elt, idx) \
+ ((elt)->slots[UAO_SWHASH_ELT_PAGESLOT_IDX(idx)])
-/* given an ELT and a page index, find the swap slot */
-#define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \
- ((ELT)->slots[UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX)])
-
-/* given an ELT, return its pageidx base */
-#define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \
- ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT)
-
-/*
- * the swhash hash function
- */
+/* Given an ELT, return its pageidx base. */
+#define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \
+ ((elt)->tag << UAO_SWHASH_CLUSTER_SHIFT)
-#define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \
- (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \
- & (AOBJ)->u_swhashmask)])
+/* The hash function. */
+#define UAO_SWHASH_HASH(aobj, idx) \
+ (&(aobj)->u_swhash[(((idx) >> UAO_SWHASH_CLUSTER_SHIFT) \
+ & (aobj)->u_swhashmask)])
/*
- * the swhash threshhold determines if we will use an array or a
+ * The threshold which determines whether we will use an array or a
* hash table to store the list of allocated swap blocks.
*/
-
-#define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4)
-#define UAO_USES_SWHASH(AOBJ) \
- ((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */
-
-/*
- * the number of buckets in a swhash, with an upper bound
- */
-
-#define UAO_SWHASH_MAXBUCKETS 256
-#define UAO_SWHASH_BUCKETS(AOBJ) \
- (MIN((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \
- UAO_SWHASH_MAXBUCKETS))
+#define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4)
+#define UAO_USES_SWHASH(aobj) \
+ ((aobj)->u_pages > UAO_SWHASH_THRESHOLD)
+
+/* The number of buckets in a hash, with an upper bound. */
+#define UAO_SWHASH_MAXBUCKETS 256
+#define UAO_SWHASH_BUCKETS(aobj) \
+ (MIN((aobj)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, UAO_SWHASH_MAXBUCKETS))
/*
* uao_swhash_elt: when a hash table is being used, this structure defines
@@ -135,7 +124,7 @@ LIST_HEAD(uao_swhash, uao_swhash_elt);
* uao_swhash_elt_pool: pool of uao_swhash_elt structures.
* Note: pages for this pool must not come from a pageable kernel map.
*/
-static struct pool uao_swhash_elt_pool;
+static struct pool uao_swhash_elt_pool __cacheline_aligned;
/*
* uvm_aobj: the actual anon-backed uvm_object
@@ -159,25 +148,17 @@ struct uvm_aobj {
LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */
};
-/*
- * local functions
- */
-
static void uao_free(struct uvm_aobj *);
static int uao_get(struct uvm_object *, voff_t, struct vm_page **,
int *, int, vm_prot_t, int, int);
static int uao_put(struct uvm_object *, voff_t, voff_t, int);
-static void uao_detach_locked(struct uvm_object *);
-static void uao_reference_locked(struct uvm_object *);
-
#if defined(VMSWAP)
static struct uao_swhash_elt *uao_find_swhash_elt
(struct uvm_aobj *, int, bool);
static bool uao_pagein(struct uvm_aobj *, int, int);
static bool uao_pagein_page(struct uvm_aobj *, int);
-static void uao_dropswap_range1(struct uvm_aobj *, voff_t, voff_t);
#endif /* defined(VMSWAP) */
/*
@@ -197,12 +178,8 @@ const struct uvm_pagerops aobj_pager = {
* uao_list: global list of active aobjs, locked by uao_list_lock
*/
-static LIST_HEAD(aobjlist, uvm_aobj) uao_list;
-static kmutex_t uao_list_lock;
-
-/*
- * functions
- */
+static LIST_HEAD(aobjlist, uvm_aobj) uao_list __cacheline_aligned;
+static kmutex_t uao_list_lock __cacheline_aligned;
/*
* hash table/array related functions
@@ -272,7 +249,7 @@ uao_find_swslot(struct uvm_object *uobj,
*/
if (aobj->u_flags & UAO_FLAG_NOSWAP)
- return(0);
+ return 0;
/*
* if hashing, look in hash table.
@@ -280,17 +257,14 @@ uao_find_swslot(struct uvm_object *uobj,
if (UAO_USES_SWHASH(aobj)) {
elt = uao_find_swhash_elt(aobj, pageidx, false);
- if (elt)
- return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx));
- else
- return(0);
+ return elt ? UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) : 0;
}
/*
* otherwise, look in the array
*/
- return(aobj->u_swslots[pageidx]);
+ return aobj->u_swslots[pageidx];
}
/*
@@ -319,11 +293,8 @@ uao_set_swslot(struct uvm_object *uobj,
*/
if (aobj->u_flags & UAO_FLAG_NOSWAP) {
- if (slot == 0)
- return(0);
-
- printf("uao_set_swslot: uobj = %p\n", uobj);
- panic("uao_set_swslot: NOSWAP object");
+ KASSERTMSG(slot == 0, "uao_set_swslot: no swap object");
+ return 0;
}
/*
@@ -368,7 +339,7 @@ uao_set_swslot(struct uvm_object *uobj,
oldslot = aobj->u_swslots[pageidx];
aobj->u_swslots[pageidx] = slot;
}
- return (oldslot);
+ return oldslot;
}
#endif /* defined(VMSWAP) */
@@ -386,12 +357,11 @@ uao_set_swslot(struct uvm_object *uobj,
static void
uao_free(struct uvm_aobj *aobj)
{
+ struct uvm_object *uobj = &aobj->u_obj;
-#if defined(VMSWAP)
- uao_dropswap_range1(aobj, 0, 0);
-#endif /* defined(VMSWAP) */
-
- mutex_exit(aobj->u_obj.vmobjlock);
+ KASSERT(mutex_owned(uobj->vmobjlock));
+ uao_dropswap_range(uobj, 0, 0);
+ mutex_exit(uobj->vmobjlock);
#if defined(VMSWAP)
if (UAO_USES_SWHASH(aobj)) {
@@ -415,7 +385,7 @@ uao_free(struct uvm_aobj *aobj)
* finally free the aobj itself
*/
- uvm_obj_destroy(&aobj->u_obj, true);
+ uvm_obj_destroy(uobj, true);
kmem_free(aobj, sizeof(struct uvm_aobj));
}
@@ -493,7 +463,7 @@ uao_create(vsize_t size, int flags)
if (flags) {
aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */
- return(&aobj->u_obj);
+ return &aobj->u_obj;
}
}
@@ -519,8 +489,6 @@ uao_create(vsize_t size, int flags)
return(&aobj->u_obj);
}
-
-
/*
* uao_init: set up aobj pager subsystem
*
@@ -542,124 +510,62 @@ uao_init(void)
}
/*
- * uao_reference: add a ref to an aobj
- *
- * => aobj must be unlocked
- * => just lock it and call the locked version
+ * uao_reference: hold a reference to an anonymous UVM object.
*/
-
void
uao_reference(struct uvm_object *uobj)
{
-
- /*
- * kernel_object already has plenty of references, leave it alone.
- */
-
- if (UVM_OBJ_IS_KERN_OBJECT(uobj))
- return;
-
- mutex_enter(uobj->vmobjlock);
- uao_reference_locked(uobj);
- mutex_exit(uobj->vmobjlock);
-}
-
-/*
- * uao_reference_locked: add a ref to an aobj that is already locked
- *
- * => aobj must be locked
- * this needs to be separate from the normal routine
- * since sometimes we need to add a reference to an aobj when
- * it's already locked.
- */
-
-static void
-uao_reference_locked(struct uvm_object *uobj)
-{
- UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist);
-
- /*
- * kernel_object already has plenty of references, leave it alone.
- */
-
- if (UVM_OBJ_IS_KERN_OBJECT(uobj))
+ /* Kernel object is persistent. */
+ if (UVM_OBJ_IS_KERN_OBJECT(uobj)) {
return;
-
- uobj->uo_refs++;
- UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)",
- uobj, uobj->uo_refs,0,0);
+ }
+ atomic_inc_uint(&uobj->uo_refs);
}
/*
- * uao_detach: drop a reference to an aobj
- *
- * => aobj must be unlocked
- * => just lock it and call the locked version
+ * uao_detach: drop a reference to an anonymous UVM object.
*/
-
void
uao_detach(struct uvm_object *uobj)
{
-
- /*
- * detaching from kernel_object is a noop.
- */
-
- if (UVM_OBJ_IS_KERN_OBJECT(uobj))
- return;
-
- mutex_enter(uobj->vmobjlock);
- uao_detach_locked(uobj);
-}
-
-/*
- * uao_detach_locked: drop a reference to an aobj
- *
- * => aobj must be locked, and is unlocked (or freed) upon return.
- * this needs to be separate from the normal routine
- * since sometimes we need to detach from an aobj when
- * it's already locked.
- */
-
-static void
-uao_detach_locked(struct uvm_object *uobj)
-{
struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
struct vm_page *pg;
+
UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist);
/*
- * detaching from kernel_object is a noop.
- */
+ * Detaching from kernel object is a NOP.
+ */
- if (UVM_OBJ_IS_KERN_OBJECT(uobj)) {
- mutex_exit(uobj->vmobjlock);
+ if (UVM_OBJ_IS_KERN_OBJECT(uobj))
return;
- }
+
+ /*
+ * Drop the reference. If it was the last one, destroy the object.
+ */
UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0);
- uobj->uo_refs--;
- if (uobj->uo_refs) {
- mutex_exit(uobj->vmobjlock);
+ if (atomic_dec_uint_nv(&uobj->uo_refs) > 0) {
UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0);
return;
}
/*
- * remove the aobj from the global list.
- */
+ * Remove the aobj from the global list.
+ */
mutex_enter(&uao_list_lock);
LIST_REMOVE(aobj, u_list);
mutex_exit(&uao_list_lock);
/*
- * free all the pages left in the aobj. for each page,
- * when the page is no longer busy (and thus after any disk i/o that
- * it's involved in is complete), release any swap resources and
- * free the page itself.
- */
+ * Free all the pages left in the aobj. For each page, when the
+ * page is no longer busy (and thus after any disk I/O that it is
+ * involved in is complete), release any swap resources and free
+ * the page itself.
+ */
+ mutex_enter(uobj->vmobjlock);
mutex_enter(&uvm_pageqlock);
while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL) {
pmap_page_protect(pg, VM_PROT_NONE);
@@ -678,8 +584,8 @@ uao_detach_locked(struct uvm_object *uob
mutex_exit(&uvm_pageqlock);
/*
- * finally, free the aobj itself.
- */
+ * Finally, free the anonymous UVM object itself.
+ */
uao_free(aobj);
}
@@ -915,9 +821,6 @@ static int
uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps,
int *npagesp, int centeridx, vm_prot_t access_type, int advice, int flags)
{
-#if defined(VMSWAP)
- struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
-#endif /* defined(VMSWAP) */
voff_t current_offset;
struct vm_page *ptmp = NULL; /* Quell compiler warning */
int lcv, gotpages, maxpages, swslot, pageidx;
@@ -959,7 +862,7 @@ uao_get(struct uvm_object *uobj, voff_t
* zero-fill'd.
*/
- if (ptmp == NULL && uao_find_swslot(&aobj->u_obj,
+ if (ptmp == NULL && uao_find_swslot(uobj,
current_offset >> PAGE_SHIFT) == 0) {
ptmp = uvm_pagealloc(uobj, current_offset,
NULL, UVM_FLAG_COLORMATCH|UVM_PGA_ZERO);
@@ -1122,7 +1025,7 @@ gotpage:
* do the needed "i/o", either reading from swap or zeroing.
*/
- swslot = uao_find_swslot(&aobj->u_obj, pageidx);
+ swslot = uao_find_swslot(uobj, pageidx);
/*
* just zero the page if there's nothing in swap.
@@ -1168,8 +1071,8 @@ gotpage:
* it from being used again.
*/
- swslot = uao_set_swslot(&aobj->u_obj, pageidx,
- SWSLOT_BAD);
+ swslot = uao_set_swslot(uobj, pageidx,
+ SWSLOT_BAD);
if (swslot > 0) {
uvm_swap_markbad(swslot, 1);
}
@@ -1244,74 +1147,56 @@ uao_dropswap(struct uvm_object *uobj, in
bool
uao_swap_off(int startslot, int endslot)
{
- struct uvm_aobj *aobj, *nextaobj;
- bool rv;
+ struct uvm_aobj *aobj;
/*
- * walk the list of all aobjs.
+ * Walk the list of all anonymous UVM objects. Grab the first.
*/
-
-restart:
mutex_enter(&uao_list_lock);
- for (aobj = LIST_FIRST(&uao_list);
- aobj != NULL;
- aobj = nextaobj) {
-
- /*
- * try to get the object lock, start all over if we fail.
- * most of the time we'll get the aobj lock,
- * so this should be a rare case.
- */
-
- if (!mutex_tryenter(aobj->u_obj.vmobjlock)) {
- mutex_exit(&uao_list_lock);
- /* XXX Better than yielding but inadequate. */
- kpause("livelock", false, 1, NULL);
- goto restart;
- }
-
- /*
- * add a ref to the aobj so it doesn't disappear
- * while we're working.
- */
+ if ((aobj = LIST_FIRST(&uao_list)) == NULL) {
+ mutex_exit(&uao_list_lock);
+ return false;
+ }
+ uao_reference(&aobj->u_obj);
- uao_reference_locked(&aobj->u_obj);
+ do {
+ struct uvm_aobj *nextaobj;
+ bool rv;
/*
- * now it's safe to unlock the uao list.
+ * Prefetch the next object and immediately hold a reference
+ * on it, so neither the current nor the next entry could
+ * disappear while we are iterating.
*/
-
+ if ((nextaobj = LIST_NEXT(aobj, u_list)) != NULL) {
+ uao_reference(&nextaobj->u_obj);
+ }
mutex_exit(&uao_list_lock);
/*
- * page in any pages in the swslot range.
- * if there's an error, abort and return the error.
+ * Page in all pages in the swap slot range.
*/
-
+ mutex_enter(aobj->u_obj.vmobjlock);
rv = uao_pagein(aobj, startslot, endslot);
+ mutex_exit(aobj->u_obj.vmobjlock);
+
+ /* Drop the reference of the current object. */
+ uao_detach(&aobj->u_obj);
if (rv) {
- uao_detach_locked(&aobj->u_obj);
+ if (nextaobj) {
+ uao_detach(&nextaobj->u_obj);
+ }
return rv;
}
- /*
- * we're done with this aobj.
- * relock the list and drop our ref on the aobj.
- */
-
+ aobj = nextaobj;
mutex_enter(&uao_list_lock);
- nextaobj = LIST_NEXT(aobj, u_list);
- uao_detach_locked(&aobj->u_obj);
- }
+ } while (aobj);
- /*
- * done with traversal, unlock the list
- */
mutex_exit(&uao_list_lock);
return false;
}
-
/*
* page in any pages from aobj in the given range.
*
@@ -1391,30 +1276,31 @@ restart:
}
/*
- * page in a page from an aobj. used for swap_off.
- * returns true if pagein was aborted due to lack of memory.
+ * uao_pagein_page: page in a single page from an anonymous UVM object.
*
- * => aobj must be locked and is returned locked.
+ * => Returns true if pagein was aborted due to lack of memory.
+ * => Object must be locked and is returned locked.
*/
static bool
uao_pagein_page(struct uvm_aobj *aobj, int pageidx)
{
+ struct uvm_object *uobj = &aobj->u_obj;
struct vm_page *pg;
int rv, npages;
pg = NULL;
npages = 1;
- /* locked: aobj */
- rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT,
- &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, PGO_SYNCIO);
- /* unlocked: aobj */
+
+ KASSERT(mutex_owned(uobj->vmobjlock));
+ rv = uao_get(uobj, pageidx << PAGE_SHIFT, &pg, &npages,
+ 0, VM_PROT_READ | VM_PROT_WRITE, 0, PGO_SYNCIO);
/*
* relock and finish up.
*/
- mutex_enter(aobj->u_obj.vmobjlock);
+ mutex_enter(uobj->vmobjlock);
switch (rv) {
case 0:
break;
@@ -1468,17 +1354,10 @@ void
uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end)
{
struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
+ int swpgonlydelta = 0;
KASSERT(mutex_owned(uobj->vmobjlock));
- uao_dropswap_range1(aobj, start, end);
-}
-
-static void
-uao_dropswap_range1(struct uvm_aobj *aobj, voff_t start, voff_t end)
-{
- int swpgonlydelta = 0;
-
if (end == 0) {
end = INT64_MAX;
}
Index: src/sys/uvm/uvm_aobj.h
diff -u src/sys/uvm/uvm_aobj.h:1.21 src/sys/uvm/uvm_aobj.h:1.21.10.1
--- src/sys/uvm/uvm_aobj.h:1.21 Wed Feb 2 15:28:38 2011
+++ src/sys/uvm/uvm_aobj.h Thu Nov 22 20:25:21 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_aobj.h,v 1.21 2011/02/02 15:28:38 chuck Exp $ */
+/* $NetBSD: uvm_aobj.h,v 1.21.10.1 2012/11/22 20:25:21 riz Exp $ */
/*
* Copyright (c) 1998 Chuck Silvers, Charles D. Cranor and
@@ -40,37 +40,31 @@
#define _UVM_UVM_AOBJ_H_
/*
- * flags
+ * Flags for uao_create: UAO_FLAG_KERNOBJ and UAO_FLAG_KERNSWAP are
+ * used only once, to initialise UVM.
*/
-
-/* flags for uao_create: can only be used one time (at bootup) */
-#define UAO_FLAG_KERNOBJ 0x1 /* create kernel object */
-#define UAO_FLAG_KERNSWAP 0x2 /* enable kernel swap */
-
-/* internal flags */
-#define UAO_FLAG_NOSWAP 0x8 /* aobj can't swap (kernel obj only!) */
+#define UAO_FLAG_KERNOBJ 0x1 /* create kernel object */
+#define UAO_FLAG_KERNSWAP 0x2 /* enable kernel swap */
+#define UAO_FLAG_NOSWAP 0x8 /* aobj may not swap */
#ifdef _KERNEL
#if defined(_KERNEL_OPT)
#include "opt_vmswap.h"
#endif
-/*
- * prototypes
- */
+void uao_init(void);
+int uao_set_swslot(struct uvm_object *, int, int);
-void uao_init(void);
-int uao_set_swslot(struct uvm_object *, int, int);
-#if defined(VMSWAP)
-int uao_find_swslot(struct uvm_object *, int);
-void uao_dropswap(struct uvm_object *, int);
-bool uao_swap_off(int, int);
-void uao_dropswap_range(struct uvm_object *, voff_t, voff_t);
-#else /* defined(VMSWAP) */
+#if defined(VMSWAP)
+int uao_find_swslot(struct uvm_object *, int);
+void uao_dropswap(struct uvm_object *, int);
+bool uao_swap_off(int, int);
+void uao_dropswap_range(struct uvm_object *, voff_t, voff_t);
+#else
#define uao_find_swslot(obj, off) 0
#define uao_dropswap(obj, off) /* nothing */
#define uao_dropswap_range(obj, lo, hi) /* nothing */
-#endif /* defined(VMSWAP) */
+#endif
#endif /* _KERNEL */
Index: src/sys/uvm/uvm_object.h
diff -u src/sys/uvm/uvm_object.h:1.32 src/sys/uvm/uvm_object.h:1.32.2.1
--- src/sys/uvm/uvm_object.h:1.32 Sat Jan 28 14:37:35 2012
+++ src/sys/uvm/uvm_object.h Thu Nov 22 20:25:21 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_object.h,v 1.32 2012/01/28 14:37:35 rmind Exp $ */
+/* $NetBSD: uvm_object.h,v 1.32.2.1 2012/11/22 20:25:21 riz Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -48,6 +48,9 @@
* is the case for tmpfs and layered file systems. In such case, vnode's
* UVM object and the underlying UVM object shares the lock (note that the
* vnode_t::v_interlock points to uvm_object::vmobjlock).
+ *
+ * The reference count is managed atomically for the anonymous UVM objects.
+ * For other objects, it is arbitrary (may use the lock or atomics).
*/
struct uvm_object {
