Page MenuHomeFreeBSD
Files F160290545

D43622.diff
No OneTemporary
Actions

D43622.diff
View Options

diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -426,6 +426,7 @@
#define VM_MAP_WIRE_HOLESOK 2 /* region may have holes */
#define VM_MAP_WIRE_WRITE 4 /* Validate writable. */
+#define VM_MAP_WIRE_PREFAULT 8 /* Pre-populate whole region. */
typedef int vm_map_entry_reader(void *token, vm_map_entry_t addr,
vm_map_entry_t dest);
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -3486,6 +3486,86 @@
entry->wired_count = -1;
}
+/*
+ * vm_map_wire_prefault_entry:
+ *
+ * Preallocates pages in object to avoid performance penalties in
+ * 'vm_fault'. Used for speeding up wirings of large regions.
+ *
+ * Will not operate on non-empty entries.
+ */
+
+static int
+vm_map_wire_prefault_entry(vm_map_t map, vm_map_entry_t entry)
+{
+ vm_pindex_t pindex;
+ vm_offset_t cur, end;
+ vm_object_t obj = entry->object.vm_object;
+ int rv = KERN_SUCCESS;
+ vm_page_t m;
+#if VM_NRESERVLEVEL > 0
+ const size_t reserv_size = 1 << (VM_LEVEL_0_ORDER + PAGE_SHIFT);
+#endif
+
+ VM_OBJECT_WLOCK(obj);
+ /* Check if the entry is empty. */
+ m = vm_page_find_least(obj, OFF_TO_IDX(entry->offset));
+ if (m != NULL
+ && m->pindex <= OFF_TO_IDX((entry->end - entry->start) + entry->offset)){
+ VM_OBJECT_WUNLOCK(obj);
+ return (KERN_RESTART);
+ }
+ /* Populate entry's object with pages. */
+ end = entry->end;
+ cur = entry->start;
+ while (cur < end) {
+ pindex = OFF_TO_IDX((cur - entry->start) + entry->offset);
+#if VM_NRESERVLEVEL > 0
+ /* First run - try to allocate a superpage. */
+ if ((cur & (reserv_size - 1)) == 0 &&
+ (end - cur) >= reserv_size) {
+ m = vm_page_alloc_contig(obj, pindex,
+ VM_ALLOC_WIRED | VM_ALLOC_NOBUSY,
+ (1 << VM_LEVEL_0_ORDER), 0, ~0, 0, 0,
+ VM_MEMATTR_DEFAULT);
+ if (m != NULL) {
+ cur += reserv_size;
+ continue;
+ }
+ }
+#endif
+ /* Fall back to 0-order pages. */
+ m = vm_page_alloc(obj, pindex,
+ VM_ALLOC_WIRED | VM_ALLOC_NOBUSY);
+ if (m == NULL) {
+ VM_OBJECT_WUNLOCK(obj);
+ return (KERN_NO_SPACE);
+ }
+ /* We got a 0-order page. */
+ cur += PAGE_SIZE;
+ }
+ VM_OBJECT_WUNLOCK(obj);
+
+ /*
+ * Simulate faults to enter the previously
+ * allocated pages into the physical map.
+ */
+ cur = entry->start;
+ while (cur < end) {
+ rv = vm_fault(map, cur, VM_PROT_NONE, VM_FAULT_WIRE, NULL);
+ if (rv != KERN_SUCCESS)
+ break;
+
+ VM_OBJECT_RLOCK(obj);
+ m = vm_page_lookup(obj,
+ OFF_TO_IDX((cur - entry->start) + entry->offset));
+ VM_OBJECT_RUNLOCK(obj);
+
+ cur += pagesizes[m->psind];
+ }
+ return (rv);
+}
+
int
vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
{
@@ -3595,6 +3675,13 @@
vm_map_busy(map);
vm_map_unlock(map);
+ if ((flags & VM_MAP_WIRE_PREFAULT) != 0 && user_wire &&
+ !holes_ok) {
+ rv = vm_map_wire_prefault_entry(map, entry);
+ if (rv != KERN_RESTART)
+ goto fault_done;
+ /* Fall back to the regular wiring loop. */
+ }
for (faddr = saved_start; faddr < saved_end;
faddr += incr) {
/*
@@ -3606,6 +3693,7 @@
if (rv != KERN_SUCCESS)
break;
}
+fault_done:
vm_map_lock(map);
vm_map_unbusy(map);
if (last_timestamp + 1 != map->timestamp) {

File Metadata

Mime Type
text/plain
Expires
Tue, Jun 23, 11:45 PM (9 h, 44 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
34263661
Default Alt Text
D43622.diff (3 KB)

Event Timeline