git: c8ffb90b1dd3 - main - Revert "vm_page: drop mpred from grab_valid_iter()"

The branch main has been updated by dougm:

URL: https://cgit.FreeBSD.org/src/commit/?id=c8ffb90b1dd391b88b67f66028833876497d5d78

commit c8ffb90b1dd391b88b67f66028833876497d5d78
Author:     Doug Moore <dougm@FreeBSD.org>
AuthorDate: 2025-05-20 08:08:43 +0000
Commit:     Doug Moore <dougm@FreeBSD.org>
CommitDate: 2025-05-20 08:08:43 +0000

    Revert "vm_page: drop mpred from grab_valid_iter()"
    
    This reverts commit 0f941203ac513f5ed3cf30038ac9e7a062acf1b7.
    
    Removing the unread variable also removed a side-effect of computing a
    value to assign to that variable, and that side-effect was critical.
---
 sys/vm/vm_page.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 85a39aa8c22e..ea6fbdbc6386 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -4880,7 +4880,7 @@ int
 vm_page_grab_valid_iter(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex,
     int allocflags, struct pctrie_iter *pages)
 {
-	vm_page_t m;
+	vm_page_t m, mpred;
 	vm_page_t ma[VM_INITIAL_PAGEIN];
 	int after, i, pflags, rv;
 
@@ -4924,6 +4924,7 @@ retrylookup:
 		*mp = NULL;
 		return (VM_PAGER_FAIL);
 	} else {
+		mpred = vm_radix_iter_lookup_lt(pages, pindex);
 		m = vm_page_alloc_iter(object, pindex, pflags, pages);
 		if (m == NULL) {
 			if (!vm_pager_can_alloc_page(object, pindex)) {
@@ -4940,7 +4941,7 @@ retrylookup:
 		after = MIN(after, VM_INITIAL_PAGEIN);
 		after = MIN(after, allocflags >> VM_ALLOC_COUNT_SHIFT);
 		after = MAX(after, 1);
-		ma[0] = m;
+		ma[0] = mpred = m;
 		pctrie_iter_reset(pages);
 		for (i = 1; i < after; i++) {
 			m = vm_radix_iter_lookup(pages, pindex + i);
@@ -4951,6 +4952,7 @@ retrylookup:
 					break;
 			} else if (vm_page_any_valid(m) || !vm_page_tryxbusy(m))
 				break;
+			mpred = ma[i] = m;
 		}
 		after = i;
 		vm_object_pip_add(object, after);