git: 45cde0e43918 - main - vm_page: add vm_page_clearref() helper

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=45cde0e439188589ca2511f6fd76829cbf68267e

commit 45cde0e439188589ca2511f6fd76829cbf68267e
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2024-07-08 17:45:33 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2024-07-15 06:15:50 +0000

    vm_page: add vm_page_clearref() helper
    
    It is supposed to be used for ref_count manipulations when the pages
    are owned by an object, but ref_count is used for something else than
    the wiring, e.g. PTE population count on the page table page.
    
    Reviewed by:    markj
    Sponsored by:   Advanced Micro Devices (AMD)
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D45910
---
 sys/vm/vm_page.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index f419ba8e3d34..49f4c0fbc0cb 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -947,6 +947,17 @@ vm_page_in_laundry(vm_page_t m)
 	return (queue == PQ_LAUNDRY || queue == PQ_UNSWAPPABLE);
 }
 
+static inline void
+vm_page_clearref(vm_page_t m)
+{
+	u_int r;
+
+	r = m->ref_count;
+	while (atomic_fcmpset_int(&m->ref_count, &r, r & (VPRC_BLOCKED |
+	    VPRC_OBJREF)) == 0)
+		;
+}
+
 /*
  *	vm_page_drop:
  *