Implement global and per-uid accounting of the anonymous memory. Add

rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved
for the uid.

The accounting information (charge) is associated with either map entry,
or vm object backing the entry, assuming the object is the first one
in the shadow chain and entry does not require COW. Charge is moved
from entry to object on allocation of the object, e.g. during the mmap,
assuming the object is allocated, or on the first page fault on the
entry. It moves back to the entry on forks due to COW setup.

The per-entry granularity of accounting makes the charge process fair
for processes that change uid during lifetime, and decrements charge
for proper uid when region is unmapped.

The interface of vm_pager_allocate(9) is extended by adding struct ucred *,
that is used to charge appropriate uid when allocation if performed by
kernel, e.g. md(4).

Several syscalls, among them is fork(2), may now return ENOMEM when
global or per-uid limits are enforced.

In collaboration with:	pho
Reviewed by:	alc
Approved by:	re (kensmith)

1 files changed, 4 insertions, 2 deletions

diff --git a/sys/vm/vm_pager.h b/sys/vm/vm_pager.h
index 7acc04e..7c8aeba 100644
--- a/sys/vm/vm_pager.h
+++ b/sys/vm/vm_pager.h
@@ -47,7 +47,8 @@
 TAILQ_HEAD(pagerlst, vm_object);
 
 typedef void pgo_init_t(void);
-typedef vm_object_t pgo_alloc_t(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
+typedef vm_object_t pgo_alloc_t(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t,
+    struct ucred *);
 typedef void pgo_dealloc_t(vm_object_t);
 typedef int pgo_getpages_t(vm_object_t, vm_page_t *, int, int);
 typedef void pgo_putpages_t(vm_object_t, vm_page_t *, int, int, int *);
@@ -100,7 +101,8 @@ extern vm_map_t pager_map;
 extern struct pagerops *pagertab[];
 extern struct mtx pbuf_mtx;
 
-vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
+vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t,
+    vm_ooffset_t, struct ucred *);
 void vm_pager_bufferinit(void);
 void vm_pager_deallocate(vm_object_t);
 static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);