git: 44a0bdad29d7 - stable/13 - sysctl vm.objects: report backing object and swap use

[Konstantin Belousov]

The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=44a0bdad29d71e350ba752fc5414e17021485f6b

commit 44a0bdad29d71e350ba752fc5414e17021485f6b
Author:     Konstantin Belousov <kib at FreeBSD.org>
AuthorDate: 2021-04-15 09:27:02 +0000
Commit:     Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-04-23 11:14:11 +0000

    sysctl vm.objects: report backing object and swap use
    
    (cherry picked from commit ecfbddf0cde3d4151217e3eb2d7c5388a423d397)
---
 sys/kern/kern_proc.c |  3 +++
 sys/sys/user.h       | 20 ++++++++++++++++----
 sys/vm/swap_pager.c  | 23 +++++++++++++++++++++++
 sys/vm/swap_pager.h  |  1 +
 sys/vm/vm_object.c   | 13 ++++++++++++-
 5 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index f8fed2573712..d2414df60d7a 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -2538,6 +2538,9 @@ kern_proc_vmmap_out(struct proc *p, struct sbuf *sb, ssize_t maxlen, int flags)
 		bzero(kve, sizeof(*kve));
 		obj = entry->object.vm_object;
 		if (obj != NULL) {
+			if ((obj->flags & OBJ_ANON) != 0)
+				kve->kve_obj = (uintptr_t)obj;
+
 			for (tobj = obj; tobj != NULL;
 			    tobj = tobj->backing_object) {
 				VM_OBJECT_RLOCK(tobj);
diff --git a/sys/sys/user.h b/sys/sys/user.h
index f882e7dcd699..14471c91572f 100644
--- a/sys/sys/user.h
+++ b/sys/sys/user.h
@@ -529,12 +529,17 @@ struct kinfo_vmentry {
 	uint32_t kve_vn_rdev_freebsd11;		/* Device id if device. */
 	uint16_t kve_vn_mode;			/* File mode. */
 	uint16_t kve_status;			/* Status flags. */
-	uint64_t kve_vn_fsid;			/* dev_t of vnode location */
+	union {
+		uint64_t _kve_vn_fsid;		/* dev_t of vnode location */
+		uint64_t _kve_obj;		/* handle of anon obj */
+	} kve_type_spec;
 	uint64_t kve_vn_rdev;			/* Device id if device. */
 	int	 _kve_ispare[8];		/* Space for more stuff. */
 	/* Truncated before copyout in sysctl */
 	char	 kve_path[PATH_MAX];		/* Path to VM obj, if any. */
 };
+#define	kve_vn_fsid	kve_type_spec._kve_vn_fsid
+#define	kve_obj		kve_type_spec._kve_obj
 
 /*
  * The "vm.objects" sysctl provides a list of all VM objects in the system
@@ -552,11 +557,18 @@ struct kinfo_vmobject {
 	uint64_t kvo_resident;			/* Number of resident pages. */
 	uint64_t kvo_active;			/* Number of active pages. */
 	uint64_t kvo_inactive;			/* Number of inactive pages. */
-	uint64_t kvo_vn_fsid;
-	uint64_t _kvo_qspare[7];
-	uint32_t _kvo_ispare[8];
+	union {
+		uint64_t _kvo_vn_fsid;
+		uint64_t _kvo_backing_obj;	/* Handle for the backing obj */
+	} kvo_type_spec;			/* Type-specific union */
+	uint64_t kvo_me;			/* Uniq handle for anon obj */
+	uint64_t _kvo_qspare[6];
+	uint32_t kvo_swapped;			/* Number of swapped pages */
+	uint32_t _kvo_ispare[7];
 	char	kvo_path[PATH_MAX];		/* Pathname, if any. */
 };
+#define	kvo_vn_fsid	kvo_type_spec._kvo_vn_fsid
+#define	kvo_backing_obj	kvo_type_spec._kvo_backing_obj
 
 /*
  * The KERN_PROC_KSTACK sysctl allows a process to dump the kernel stacks of
diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 3789a0217252..888df04741b4 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -1763,6 +1763,29 @@ swp_pager_force_dirty(vm_page_t m)
 	vm_page_launder(m);
 }
 
+u_long
+swap_pager_swapped_pages(vm_object_t object)
+{
+	struct swblk *sb;
+	vm_pindex_t pi;
+	u_long res;
+	int i;
+
+	VM_OBJECT_ASSERT_LOCKED(object);
+	if (object->type != OBJT_SWAP)
+		return (0);
+
+	for (res = 0, pi = 0; (sb = SWAP_PCTRIE_LOOKUP_GE(
+	    &object->un_pager.swp.swp_blks, pi)) != NULL;
+	    pi = sb->p + SWAP_META_PAGES) {
+		for (i = 0; i < SWAP_META_PAGES; i++) {
+			if (sb->d[i] != SWAPBLK_NONE)
+				res++;
+		}
+	}
+	return (res);
+}
+
 /*
  *	swap_pager_swapoff_object:
  *
diff --git a/sys/vm/swap_pager.h b/sys/vm/swap_pager.h
index 80dca93fbf85..59ca2cc2cfdb 100644
--- a/sys/vm/swap_pager.h
+++ b/sys/vm/swap_pager.h
@@ -81,6 +81,7 @@ void swap_pager_swap_init(void);
 int swap_pager_nswapdev(void);
 int swap_pager_reserve(vm_object_t, vm_pindex_t, vm_size_t);
 void swap_pager_status(int *total, int *used);
+u_long swap_pager_swapped_pages(vm_object_t object);
 void swapoff_all(void);
 
 #endif				/* _KERNEL */
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index 35ea9cc45fae..1f5194464b69 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -73,6 +73,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/blockcount.h>
 #include <sys/cpuset.h>
+#include <sys/limits.h>
 #include <sys/lock.h>
 #include <sys/mman.h>
 #include <sys/mount.h>
@@ -2524,6 +2525,7 @@ sysctl_vm_object_list(SYSCTL_HANDLER_ARGS)
 	struct vattr va;
 	vm_object_t obj;
 	vm_page_t m;
+	u_long sp;
 	int count, error;
 
 	if (req->oldptr == NULL) {
@@ -2590,8 +2592,17 @@ sysctl_vm_object_list(SYSCTL_HANDLER_ARGS)
 		freepath = NULL;
 		fullpath = "";
 		kvo->kvo_type = vm_object_kvme_type(obj, &vp);
-		if (vp != NULL)
+		if (vp != NULL) {
 			vref(vp);
+		} else if ((obj->flags & OBJ_ANON) != 0) {
+			MPASS(kvo->kvo_type == KVME_TYPE_DEFAULT ||
+			    kvo->kvo_type == KVME_TYPE_SWAP);
+			kvo->kvo_me = (uintptr_t)obj;
+			/* tmpfs objs are reported as vnodes */
+			kvo->kvo_backing_obj = (uintptr_t)obj->backing_object;
+			sp = swap_pager_swapped_pages(obj);
+			kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp;
+		}
 		VM_OBJECT_RUNLOCK(obj);
 		if (vp != NULL) {
 			vn_fullpath(vp, &fullpath, &freepath);