Author: kib
Date: Tue Jun 28 00:37:34 2016
New Revision: 302243
URL: https://svnweb.freebsd.org/changeset/base/302243
Log:
MFC r302063:
Avoid the active object marking for vm.vmtotal sysctl.
Modified:
stable/10/sys/vm/vm_meter.c
stable/10/sys/vm/vm_object.h
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/vm/vm_meter.c
==============================================================================
--- stable/10/sys/vm/vm_meter.c Mon Jun 27 23:34:53 2016 (r302242)
+++ stable/10/sys/vm/vm_meter.c Tue Jun 28 00:37:34 2016 (r302243)
@@ -93,29 +93,31 @@ SYSCTL_PROC(_vm, VM_LOADAVG, loadavg, CT
CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_loadavg, "S,loadavg",
"Machine loadaverage history");
+/*
+ * This function aims to determine if the object is mapped,
+ * specifically, if it is referenced by a vm_map_entry. Because
+ * objects occasionally acquire transient references that do not
+ * represent a mapping, the method used here is inexact. However, it
+ * has very low overhead and is good enough for the advisory
+ * vm.vmtotal sysctl.
+ */
+static bool
+is_object_active(vm_object_t obj)
+{
+
+ return (obj->ref_count > obj->shadow_count);
+}
+
static int
vmtotal(SYSCTL_HANDLER_ARGS)
{
- struct proc *p;
struct vmtotal total;
- vm_map_entry_t entry;
vm_object_t object;
- vm_map_t map;
- int paging;
+ struct proc *p;
struct thread *td;
- struct vmspace *vm;
bzero(&total, sizeof(total));
- /*
- * Mark all objects as inactive.
- */
- mtx_lock(&vm_object_list_mtx);
- TAILQ_FOREACH(object, &vm_object_list, object_list) {
- VM_OBJECT_WLOCK(object);
- vm_object_clear_flag(object, OBJ_ACTIVE);
- VM_OBJECT_WUNLOCK(object);
- }
- mtx_unlock(&vm_object_list_mtx);
+
/*
* Calculate process statistics.
*/
@@ -136,11 +138,15 @@ vmtotal(SYSCTL_HANDLER_ARGS)
case TDS_INHIBITED:
if (TD_IS_SWAPPED(td))
total.t_sw++;
- else if (TD_IS_SLEEPING(td) &&
- td->td_priority <= PZERO)
- total.t_dw++;
- else
- total.t_sl++;
+ else if (TD_IS_SLEEPING(td)) {
+ if (td->td_priority <= PZERO)
+ total.t_dw++;
+ else
+ total.t_sl++;
+ if (td->td_wchan ==
+ &cnt.v_free_count)
+ total.t_pw++;
+ }
break;
case TDS_CAN_RUN:
@@ -158,29 +164,6 @@ vmtotal(SYSCTL_HANDLER_ARGS)
}
}
PROC_UNLOCK(p);
- /*
- * Note active objects.
- */
- paging = 0;
- vm = vmspace_acquire_ref(p);
- if (vm == NULL)
- continue;
- map = &vm->vm_map;
- vm_map_lock_read(map);
- for (entry = map->header.next;
- entry != &map->header; entry = entry->next) {
- if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) ||
- (object = entry->object.vm_object) == NULL)
- continue;
- VM_OBJECT_WLOCK(object);
- vm_object_set_flag(object, OBJ_ACTIVE);
- paging |= object->paging_in_progress;
- VM_OBJECT_WUNLOCK(object);
- }
- vm_map_unlock_read(map);
- vmspace_free(vm);
- if (paging)
- total.t_pw++;
}
sx_sunlock(&allproc_lock);
/*
@@ -206,9 +189,18 @@ vmtotal(SYSCTL_HANDLER_ARGS)
*/
continue;
}
+ if (object->ref_count == 1 &&
+ (object->flags & OBJ_NOSPLIT) != 0) {
+ /*
+ * Also skip otherwise unreferenced swap
+ * objects backing tmpfs vnodes, and POSIX or
+ * SysV shared memory.
+ */
+ continue;
+ }
total.t_vm += object->size;
total.t_rm += object->resident_page_count;
- if (object->flags & OBJ_ACTIVE) {
+ if (is_object_active(object)) {
total.t_avm += object->size;
total.t_arm += object->resident_page_count;
}
@@ -216,7 +208,7 @@ vmtotal(SYSCTL_HANDLER_ARGS)
/* shared object */
total.t_vmshr += object->size;
total.t_rmshr += object->resident_page_count;
- if (object->flags & OBJ_ACTIVE) {
+ if (is_object_active(object)) {
total.t_avmshr += object->size;
total.t_armshr += object->resident_page_count;
}
Modified: stable/10/sys/vm/vm_object.h
==============================================================================
--- stable/10/sys/vm/vm_object.h Mon Jun 27 23:34:53 2016
(r302242)
+++ stable/10/sys/vm/vm_object.h Tue Jun 28 00:37:34 2016
(r302243)
@@ -181,7 +181,6 @@ struct vm_object {
*/
#define OBJ_FICTITIOUS 0x0001 /* (c) contains fictitious
pages */
#define OBJ_UNMANAGED 0x0002 /* (c) contains unmanaged pages
*/
-#define OBJ_ACTIVE 0x0004 /* active objects */
#define OBJ_DEAD 0x0008 /* dead objects (during rundown) */
#define OBJ_NOSPLIT 0x0010 /* dont split this object */
#define OBJ_PIPWNT 0x0040 /* paging in progress wanted */
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