git: 6a07e67fb7a8 - main - vm_meter: Fix laundry accounting

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Tue, 22 Oct 2024 12:50:42 UTC
The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=6a07e67fb7a8b5687a492d9d70a10651d5933ff5

commit 6a07e67fb7a8b5687a492d9d70a10651d5933ff5
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2024-10-22 12:48:43 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2024-10-22 12:48:43 +0000

    vm_meter: Fix laundry accounting
    
    Pages in PQ_UNSWAPPABLE should be considered part of the laundry.
    Otherwise, on systems with no swap, the total amount of memory visible
    to tools like top(1) decreases.
    
    It doesn't seem very useful to have a dedicated counter for unswappable
    pages, and updating applications accordingly would be painful, so just
    lump them in with laundry for now.
    
    PR:             280846
    Reviewed by:    bnovkov, kib
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D47216
---
 sys/vm/vm_meter.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/sys/vm/vm_meter.c b/sys/vm/vm_meter.c
index faf4074ef0c6..fef28bb883e4 100644
--- a/sys/vm/vm_meter.c
+++ b/sys/vm/vm_meter.c
@@ -455,7 +455,8 @@ u_int
 vm_laundry_count(void)
 {
 
-	return (vm_pagequeue_count(PQ_LAUNDRY));
+	return (vm_pagequeue_count(PQ_LAUNDRY) +
+	    vm_pagequeue_count(PQ_UNSWAPPABLE));
 }
 
 static int
@@ -477,6 +478,18 @@ SYSCTL_PROC(_vm_stats_vm, OID_AUTO, v_pdpages,
     CTLTYPE_U64 | CTLFLAG_MPSAFE | CTLFLAG_RD, NULL, 0, sysctl_vm_pdpages, "QU",
     "Pages analyzed by pagedaemon");
 
+static int
+sysctl_vm_laundry_pages(SYSCTL_HANDLER_ARGS)
+{
+	struct vm_domain *vmd;
+	u_int ret;
+
+	vmd = arg1;
+	ret = vmd->vmd_pagequeues[PQ_LAUNDRY].pq_cnt +
+	    vmd->vmd_pagequeues[PQ_UNSWAPPABLE].pq_cnt;
+	return (SYSCTL_OUT(req, &ret, sizeof(ret)));
+}
+
 static void
 vm_domain_stats_init(struct vm_domain *vmd, struct sysctl_oid *parent)
 {
@@ -503,8 +516,9 @@ vm_domain_stats_init(struct vm_domain *vmd, struct sysctl_oid *parent)
 	    "inactpdpgs", CTLFLAG_RD,
 	    &vmd->vmd_pagequeues[PQ_INACTIVE].pq_pdpages, 0,
 	    "Inactive pages scanned by the page daemon");
-	SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(oid), OID_AUTO,
-	    "laundry", CTLFLAG_RD, &vmd->vmd_pagequeues[PQ_LAUNDRY].pq_cnt, 0,
+	SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(oid), OID_AUTO,
+	    "laundry", CTLFLAG_RD | CTLTYPE_UINT, vmd, 0,
+	    sysctl_vm_laundry_pages, "IU",
 	    "laundry pages");
 	SYSCTL_ADD_U64(NULL, SYSCTL_CHILDREN(oid), OID_AUTO,
 	    "laundpdpgs", CTLFLAG_RD,