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[src/netbsd-6]: src/sys/uvm Pull up following revision(s) (requested by rmind...
details: https://anonhg.NetBSD.org/src/rev/e3afb098428a
branches: netbsd-6
changeset: 775499:e3afb098428a
user: riz <riz%NetBSD.org@localhost>
date: Thu Nov 22 20:25:21 2012 +0000
description:
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.
diffstat:
sys/uvm/uvm_aobj.c | 363 +++++++++++++++++----------------------------------
sys/uvm/uvm_aobj.h | 36 ++--
sys/uvm/uvm_object.h | 5 +-
3 files changed, 140 insertions(+), 264 deletions(-)
diffs (truncated from 714 to 300 lines):
diff -r 9aca7fe6570e -r e3afb098428a sys/uvm/uvm_aobj.c
--- a/sys/uvm/uvm_aobj.c Thu Nov 22 18:51:48 2012 +0000
+++ b/sys/uvm/uvm_aobj.c Thu Nov 22 20:25:21 2012 +0000
@@ -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)
-/* given an ELT, return its pageidx base */
-#define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \
- ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT)
+/* The hash function. */
+#define UAO_SWHASH_HASH(aobj, idx) \
+ (&(aobj)->u_swhash[(((idx) >> UAO_SWHASH_CLUSTER_SHIFT) \
+ & (aobj)->u_swhashmask)])
/*
- * the swhash hash function
- */
-
-#define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \
- (&(AOBJ)->u_swhash[(((PAGEIDX) >> 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? */
+#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 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))
+/* 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 @@
* 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 @@
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 @@
* 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 @@
*/
if (aobj->u_flags & UAO_FLAG_NOSWAP)
- return(0);
+ return 0;
/*
* if hashing, look in hash table.
@@ -280,17 +257,14 @@
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 @@
*/
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 @@
oldslot = aobj->u_swslots[pageidx];
aobj->u_swslots[pageidx] = slot;
}
- return (oldslot);
+ return oldslot;
}
#endif /* defined(VMSWAP) */
@@ -386,12 +357,11 @@
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 @@
* 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 @@
if (flags) {
aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */
- return(&aobj->u_obj);
+ return &aobj->u_obj;
}
}
@@ -519,8 +489,6 @@
return(&aobj->u_obj);
}
-
-
/*
* uao_init: set up aobj pager subsystem
*
@@ -542,124 +510,62 @@
}
/*
- * 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))
+ /* Kernel object is persistent. */
+ if (UVM_OBJ_IS_KERN_OBJECT(uobj)) {
return;
-
- mutex_enter(uobj->vmobjlock);
- uao_reference_locked(uobj);
- mutex_exit(uobj->vmobjlock);
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