svn commit: r268466 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Wed Jul  9 19:11:57 2014
New Revision: 268466
URL: http://svnweb.freebsd.org/changeset/base/268466

Log:
  Current code in sysctl proc.vmmap, which intent is to calculate the
  amount of resident pages, in fact calculates the amount of installed
  pte entries in the region.  Resident pages which were not soft-faulted
  yet are not counted.
  
  Calculate the amount of resident pages by looking in the objects chain
  backing the region.
  
  Add a knob to disable the residency calculation at all.  For large
  sparce regions, either previous or updated algorithm runs for too long
  time, while several introspection tools do not need the (advisory) RSS
  value at all.
  
  PR:	kern/188911
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/kern/kern_proc.c

Modified: head/sys/kern/kern_proc.c
==============================================================================
--- head/sys/kern/kern_proc.c	Wed Jul  9 18:52:12 2014	(r268465)
+++ head/sys/kern/kern_proc.c	Wed Jul  9 19:11:57 2014	(r268466)
@@ -141,6 +141,10 @@ uma_zone_t proc_zone;
 int kstack_pages = KSTACK_PAGES;
 SYSCTL_INT(_kern, OID_AUTO, kstack_pages, CTLFLAG_RD, &kstack_pages, 0,
     "Kernel stack size in pages");
+static int vmmap_skip_res_cnt = 0;
+SYSCTL_INT(_kern, OID_AUTO, proc_vmmap_skip_resident_count, CTLFLAG_RW,
+    &vmmap_skip_res_cnt, 0,
+    "Skip calculation of the pages resident count in kern.proc.vmmap");
 
 CTASSERT(sizeof(struct kinfo_proc) == KINFO_PROC_SIZE);
 #ifdef COMPAT_FREEBSD32
@@ -2136,15 +2140,19 @@ int
 kern_proc_vmmap_out(struct proc *p, struct sbuf *sb)
 {
 	vm_map_entry_t entry, tmp_entry;
-	unsigned int last_timestamp;
+	struct vattr va;
+	vm_map_t map;
+	vm_page_t m;
+	vm_object_t obj, tobj, lobj;
 	char *fullpath, *freepath;
 	struct kinfo_vmentry *kve;
-	struct vattr va;
 	struct ucred *cred;
-	int error;
 	struct vnode *vp;
 	struct vmspace *vm;
-	vm_map_t map;
+	vm_pindex_t pindex;
+	vm_offset_t addr;
+	unsigned int last_timestamp;
+	int error;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
@@ -2162,44 +2170,53 @@ kern_proc_vmmap_out(struct proc *p, stru
 	vm_map_lock_read(map);
 	for (entry = map->header.next; entry != &map->header;
 	    entry = entry->next) {
-		vm_object_t obj, tobj, lobj;
-		vm_offset_t addr;
-		vm_paddr_t locked_pa;
-		int mincoreinfo;
-
 		if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 			continue;
 
 		bzero(kve, sizeof(*kve));
-
-		kve->kve_private_resident = 0;
 		obj = entry->object.vm_object;
 		if (obj != NULL) {
-			VM_OBJECT_RLOCK(obj);
+			for (tobj = obj; tobj != NULL;
+			    tobj = tobj->backing_object) {
+				VM_OBJECT_RLOCK(tobj);
+				lobj = tobj;
+			}
 			if (obj->shadow_count == 1)
 				kve->kve_private_resident =
 				    obj->resident_page_count;
-		}
-		kve->kve_resident = 0;
-		addr = entry->start;
-		while (addr < entry->end) {
-			locked_pa = 0;
-			mincoreinfo = pmap_mincore(map->pmap, addr, &locked_pa);
-			if (locked_pa != 0)
-				vm_page_unlock(PHYS_TO_VM_PAGE(locked_pa));
-			if (mincoreinfo & MINCORE_INCORE)
-				kve->kve_resident++;
-			if (mincoreinfo & MINCORE_SUPER)
-				kve->kve_flags |= KVME_FLAG_SUPER;
-			addr += PAGE_SIZE;
-		}
-
-		for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) {
-			if (tobj != obj)
-				VM_OBJECT_RLOCK(tobj);
-			if (lobj != obj)
-				VM_OBJECT_RUNLOCK(lobj);
-			lobj = tobj;
+			if (vmmap_skip_res_cnt)
+				goto skip_resident_count;
+			for (addr = entry->start; addr < entry->end;
+			    addr += PAGE_SIZE) {
+				pindex = OFF_TO_IDX(entry->offset + addr -
+				    entry->start);
+				for (tobj = obj;;) {
+					m = vm_page_lookup(tobj, pindex);
+					if (m != NULL)
+						break;
+					if (tobj->backing_object == NULL)
+						break;
+					pindex += OFF_TO_IDX(
+					    tobj->backing_object_offset);
+					tobj = tobj->backing_object;
+				}
+				if (m != NULL) {
+					if (m->psind != 0 && addr +
+					    pagesizes[1] <= entry->end) {
+						kve->kve_flags |=
+						    KVME_FLAG_SUPER;
+					}
+					kve->kve_resident += 1;
+				}
+			}
+skip_resident_count:
+			for (tobj = obj; tobj != NULL;
+			    tobj = tobj->backing_object) {
+				if (tobj != obj && tobj != lobj)
+					VM_OBJECT_RUNLOCK(tobj);
+			}
+		} else {
+			lobj = NULL;
 		}
 
 		kve->kve_start = entry->start;
@@ -2229,7 +2246,7 @@ kern_proc_vmmap_out(struct proc *p, stru
 
 		freepath = NULL;
 		fullpath = "";
-		if (lobj) {
+		if (lobj != NULL) {
 			vp = NULL;
 			switch (lobj->type) {
 			case OBJT_DEFAULT: