git: d6e77cda9be1 - main - uma: Show the count of free slabs in each per-domain keg's sysctl tree

[Mark Johnston]

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=d6e77cda9be1509ea170142cca3ff0d3b9f12e35

commit d6e77cda9be1509ea170142cca3ff0d3b9f12e35
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-09-17 16:13:47 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-09-17 18:19:05 +0000

    uma: Show the count of free slabs in each per-domain keg's sysctl tree
    
    This is useful for measuring the number of pages that could be freed
    from a NOFREE zone under memory pressure.
    
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
---
 sys/vm/uma_core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
index cdf3d482679e..12cab490781b 100644
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -2690,7 +2690,10 @@ zone_alloc_sysctl(uma_zone_t zone, void *unused)
 			    "Total pages currently allocated from VM");
 			SYSCTL_ADD_U32(NULL, SYSCTL_CHILDREN(oid), OID_AUTO,
 			    "free_items", CTLFLAG_RD, &dom->ud_free_items, 0,
-			    "items free in the slab layer");
+			    "Items free in the slab layer");
+			SYSCTL_ADD_U32(NULL, SYSCTL_CHILDREN(oid), OID_AUTO,
+			    "free_slabs", CTLFLAG_RD, &dom->ud_free_slabs, 0,
+			    "Unused slabs");
 		}
 	} else
 		SYSCTL_ADD_CONST_STRING(NULL, SYSCTL_CHILDREN(oid), OID_AUTO,