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From Charles Hannum:

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During a collapse, abort if the object is paging; the pagedaemon can
trigger a collapse, causing deadlock.  (XXX)
This commit is contained in:
thorpej 1997-02-24 22:19:26 +00:00
parent 7fb32152cc
commit 7327c8cf62
1 changed files with 29 additions and 5 deletions
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34
sys/vm/vm_object.c
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@ -1,4 +1,4 @@
/* $NetBSD: vm_object.c,v 1.43 1997/02/23 09:01:37 mrg Exp $ */
/* $NetBSD: vm_object.c,v 1.44 1997/02/24 22:19:26 thorpej Exp $ */
/*-
* Copyright (c) 1997 Charles M. Hannum. All rights reserved.
@ -1188,11 +1188,20 @@ vm_object_overlay(object)
* 3) The page is being paged in from a backing object behind the one
* we're deleting. We'll never notice this case, because the
* backing object we're deleting won't have the page.
*
* XXXXX FIXME
* Because pagedaemon can call vm_object_collapse(), we must *not*
* sleep waiting for pages.
*/
vm_object_unlock(object);
RetryRename:
#if 0 /* XXXXX FIXME */
vm_object_paging_wait(backing_object);
#else
if (vm_object_paging(backing_object))
goto fail;
#endif
/*
* While we were asleep, the parent object might have been deleted. If
* so, the backing object will now have only one reference (the one we
@ -1312,10 +1321,14 @@ RetryRename:
backing_page = vm_page_alloc(backing_object,
paged_offset);
if (backing_page == NULL) {
#if 0 /* XXXXX FIXME */
vm_object_unlock(backing_object);
VM_WAIT;
vm_object_lock(backing_object);
goto RetryRename;
#else
goto fail;
#endif
}
vm_object_paging_begin(backing_object);
@ -1340,6 +1353,12 @@ RetryRename:
goto fail;
}
#ifdef DIAGNOSTIC
if (rv != VM_PAGER_OK)
panic("vm_object_overlay: pager returned %d",
rv);
#endif
/*
* The pager might have moved the page while we
* were asleep, so look it up again.
@ -1433,8 +1452,10 @@ vm_object_bypass(object)
* the parent object.
*/
if (vm_object_paging(backing_object) ||
backing_object->pager != NULL)
backing_object->pager != NULL) {
vm_object_unlock(object);
goto fail;
}
/*
* Should have a check for a 'small' number
@ -1464,6 +1485,7 @@ vm_object_bypass(object)
/*
* Page still needed. Can't go any further.
*/
vm_object_unlock(object);
goto fail;
}
}
@ -1732,10 +1754,12 @@ _vm_object_print(object, full, pr)
if (object == NULL)
return;
iprintf(pr, "Object 0x%lx: size=0x%lx, res=%d, ref=%d, ",
iprintf(pr, "Object 0x%lx: size=0x%lx, res=%d, ref=%d, flags=0x%x, ",
(long) object, (long) object->size,
object->resident_page_count, object->ref_count);
(*pr)("pager=0x%lx+0x%lx, shadow=(0x%lx)+0x%lx\n",
object->resident_page_count, object->ref_count,
object->flags);
(*pr)("pip=%d, pager=0x%lx+0x%lx, shadow=(0x%lx)+0x%lx\n",
object->paging_in_progress,
(long) object->pager, (long) object->paging_offset,
(long) object->shadow, (long) object->shadow_offset);
(*pr)("shadowers=(");