Fix pageout deadlock

The pageout daemon uses small, internal, temporary objects to transport
the data out to memory managers, which are expected to release the data
once written out to backing store. Releasing this data is done with a
vm_deallocate call. The problem with this is that vm_map is allowed to
merge these objects, in which case vm_deallocate will only remove a
reference instead of releasing the underlying pages, causing the pageout
daemon to deadlock.

This change makes the pageout daemon mark these objects so that they
don't get merged.

* vm/vm_object.c (vm_object_bootstrap): Update template.
(vm_object_coalesce): Don't coalesce if an object is used for pageout.
* vm/vm_object.h (struct vm_object): New `used_for_pageout` member.
* vm/vm_pageout.c (vm_pageout_page): Mark new objects for pageout.

0 files changed, 0 insertions, 0 deletions