Author: markj
Date: Mon Sep 14 17:21:52 2020
New Revision: 365728
URL: https://svnweb.freebsd.org/changeset/base/365728
Log:
MFS r365718:
MFC r365437:
vm_object_split(): Handle orig_object type changes.
Approved by: re (gjb)
Modified:
releng/12.2/sys/vm/vm_object.c
Directory Properties:
releng/12.2/ (props changed)
Modified: releng/12.2/sys/vm/vm_object.c
==============================================================================
--- releng/12.2/sys/vm/vm_object.c Mon Sep 14 16:18:53 2020
(r365727)
+++ releng/12.2/sys/vm/vm_object.c Mon Sep 14 17:21:52 2020
(r365728)
@@ -1313,7 +1313,7 @@ vm_object_shadow(
void
vm_object_split(vm_map_entry_t entry)
{
- vm_page_t m, m_next;
+ vm_page_t m, m_busy, m_next;
vm_object_t orig_object, new_object, source;
vm_pindex_t idx, offidxstart;
vm_size_t size;
@@ -1370,8 +1370,14 @@ vm_object_split(vm_map_entry_t entry)
("orig_object->charge < 0"));
orig_object->charge -= ptoa(size);
}
+ m_busy = NULL;
+#ifdef INVARIANTS
+ idx = 0;
+#endif
retry:
m = vm_page_find_least(orig_object, offidxstart);
+ KASSERT(m == NULL || idx <= m->pindex - offidxstart,
+ ("%s: object %p was repopulated", __func__, orig_object));
for (; m != NULL && (idx = m->pindex - offidxstart) < size;
m = m_next) {
m_next = TAILQ_NEXT(m, listq);
@@ -1417,8 +1423,16 @@ retry:
*/
vm_reserv_rename(m, new_object, orig_object, offidxstart);
#endif
- if (orig_object->type == OBJT_SWAP)
+
+ /*
+ * orig_object's type may change while sleeping, so keep track
+ * of the beginning of the busied range.
+ */
+ if (orig_object->type == OBJT_SWAP) {
vm_page_xbusy(m);
+ if (m_busy == NULL)
+ m_busy = m;
+ }
}
if (orig_object->type == OBJT_SWAP) {
/*
@@ -1426,8 +1440,9 @@ retry:
* and new_object's locks are released and reacquired.
*/
swap_pager_copy(orig_object, new_object, offidxstart, 0);
- TAILQ_FOREACH(m, &new_object->memq, listq)
- vm_page_xunbusy(m);
+ if (m_busy != NULL)
+ TAILQ_FOREACH_FROM(m_busy, &new_object->memq, listq)
+ vm_page_xunbusy(m_busy);
}
VM_OBJECT_WUNLOCK(orig_object);
VM_OBJECT_WUNLOCK(new_object);
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