the current tracking of free static map entries is done as hand
rolled list manipulations using pointers in an rb_entry. it's really
confusing to read.
since its simple list manipulations, this replaces the hand rolled
code with an SLIST.
ok?
Index: uvm.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvm.h,v
retrieving revision 1.60
diff -u -p -r1.60 uvm.h
--- uvm.h 8 Oct 2015 15:58:38 -0000 1.60
+++ uvm.h 8 Aug 2016 11:53:57 -0000
@@ -69,7 +69,7 @@ struct uvm {
struct mutex aiodoned_lock;
/* static kernel map entry pool */
- vm_map_entry_t kentry_free; /* free page pool */
+ SLIST_HEAD(, vm_map_entry) kentry_free; /* free page pool */
/* aio_done is locked by uvm.aiodoned_lock. */
TAILQ_HEAD(, buf) aio_done; /* done async i/o reqs */
Index: uvm_map.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_map.c,v
retrieving revision 1.219
diff -u -p -r1.219 uvm_map.c
--- uvm_map.c 30 Jul 2016 16:43:44 -0000 1.219
+++ uvm_map.c 8 Aug 2016 11:53:57 -0000
@@ -1669,25 +1669,23 @@ uvm_mapent_alloc(struct vm_map *map, int
if (map->flags & VM_MAP_INTRSAFE || cold) {
mtx_enter(&uvm_kmapent_mtx);
- me = uvm.kentry_free;
- if (me == NULL) {
+ if (SLIST_EMPTY(&uvm.kentry_free)) {
ne = km_alloc(PAGE_SIZE, &kv_page, &kp_dirty,
&kd_nowait);
if (ne == NULL)
panic("uvm_mapent_alloc: cannot allocate map "
"entry");
- for (i = 0;
- i < PAGE_SIZE / sizeof(struct vm_map_entry) - 1;
- i++)
- RB_LEFT(&ne[i], daddrs.addr_entry) = &ne[i + 1];
- RB_LEFT(&ne[i], daddrs.addr_entry) = NULL;
- me = ne;
+ for (i = 0; i < PAGE_SIZE / sizeof(*ne); i++) {
+ SLIST_INSERT_HEAD(&uvm.kentry_free,
+ &ne[i], daddrs.addr_kentry);
+ }
if (ratecheck(&uvm_kmapent_last_warn_time,
&uvm_kmapent_warn_rate))
printf("uvm_mapent_alloc: out of static "
"map entries\n");
}
- uvm.kentry_free = RB_LEFT(me, daddrs.addr_entry);
+ me = SLIST_FIRST(&uvm.kentry_free);
+ SLIST_REMOVE_HEAD(&uvm.kentry_free, daddrs.addr_kentry);
uvmexp.kmapent++;
mtx_leave(&uvm_kmapent_mtx);
me->flags = UVM_MAP_STATIC;
@@ -1725,8 +1723,7 @@ uvm_mapent_free(struct vm_map_entry *me)
{
if (me->flags & UVM_MAP_STATIC) {
mtx_enter(&uvm_kmapent_mtx);
- RB_LEFT(me, daddrs.addr_entry) = uvm.kentry_free;
- uvm.kentry_free = me;
+ SLIST_INSERT_HEAD(&uvm.kentry_free, me, daddrs.addr_kentry);
uvmexp.kmapent--;
mtx_leave(&uvm_kmapent_mtx);
} else if (me->flags & UVM_MAP_KMEM) {
@@ -2795,11 +2792,10 @@ uvm_map_init(void)
/* now set up static pool of kernel map entries ... */
mtx_init(&uvm_kmapent_mtx, IPL_VM);
- uvm.kentry_free = NULL;
+ SLIST_INIT(&uvm.kentry_free);
for (lcv = 0 ; lcv < MAX_KMAPENT ; lcv++) {
- RB_LEFT(&kernel_map_entry[lcv], daddrs.addr_entry) =
- uvm.kentry_free;
- uvm.kentry_free = &kernel_map_entry[lcv];
+ SLIST_INSERT_HEAD(&uvm.kentry_free,
+ &kernel_map_entry[lcv], daddrs.addr_kentry);
}
/* initialize the map-related pools. */
Index: uvm_map.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_map.h,v
retrieving revision 1.55
diff -u -p -r1.55 uvm_map.h
--- uvm_map.h 9 Sep 2015 23:33:37 -0000 1.55
+++ uvm_map.h 8 Aug 2016 11:53:57 -0000
@@ -161,6 +161,7 @@ union vm_map_object {
struct vm_map_entry {
union {
RB_ENTRY(vm_map_entry) addr_entry; /* address tree */
+ SLIST_ENTRY(vm_map_entry) addr_kentry;
} daddrs;
union {
