diff options
Diffstat (limited to 'sys/vm/default_pager.c')
| -rw-r--r-- | sys/vm/default_pager.c | 80 |
1 files changed, 30 insertions, 50 deletions
diff --git a/sys/vm/default_pager.c b/sys/vm/default_pager.c index f334cd72d808..7fc4f6c49e00 100644 --- a/sys/vm/default_pager.c +++ b/sys/vm/default_pager.c @@ -27,14 +27,6 @@ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. - * - * The default pager is responsible for supplying backing store to unbacked - * storage. The backing store is usually swap so we just fall through to - * the swap routines. However, since swap metadata has not been assigned, - * the swap routines assign and manage the swap backing store through the - * vm_page->swapblk field. The object is only converted when the page is - * physically freed after having been cleaned and even then vm_page->swapblk - * is maintained whenever a resident page also has swap backing store. */ #include <sys/cdefs.h> @@ -53,14 +45,16 @@ __FBSDID("$FreeBSD$"); #include <vm/vm_pager.h> #include <vm/swap_pager.h> -static vm_object_t default_pager_alloc(void *, vm_ooffset_t, vm_prot_t, - vm_ooffset_t, struct ucred *); -static void default_pager_dealloc(vm_object_t); -static int default_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); -static void default_pager_putpages(vm_object_t, vm_page_t *, int, - boolean_t, int *); -static boolean_t default_pager_haspage(vm_object_t, vm_pindex_t, int *, - int *); +static vm_object_t default_pager_alloc(void *, vm_ooffset_t, vm_prot_t, + vm_ooffset_t, struct ucred *); +static void default_pager_dealloc(vm_object_t); +static int default_pager_getpages(vm_object_t, vm_page_t *, int, + int *, int *); +static void default_pager_putpages(vm_object_t, vm_page_t *, int, + boolean_t, int *); +static boolean_t default_pager_haspage(vm_object_t, vm_pindex_t, int *, + int *); + /* * pagerops for OBJT_DEFAULT - "default pager". */ @@ -73,7 +67,7 @@ struct pagerops defaultpagerops = { }; /* - * no_pager_alloc just returns an initialized object. + * Return an initialized object. */ static vm_object_t default_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, @@ -100,68 +94,54 @@ default_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, } /* - * deallocate resources associated with default objects. The default objects - * have no special resources allocated to them, but the vm_page's being used - * in this object might. Still, we do not have to do anything - we will free - * the swapblk in the underlying vm_page's when we free the vm_page or - * garbage collect the vm_page cache list. + * Deallocate resources associated with the object. */ static void -default_pager_dealloc(object) - vm_object_t object; +default_pager_dealloc(vm_object_t object) { - /* - * OBJT_DEFAULT objects have no special resources allocated to them. - */ + + /* Reserved swap is released by vm_object_destroy(). */ object->type = OBJT_DEAD; } /* - * Load pages from backing store. Since OBJT_DEFAULT is converted to - * OBJT_SWAP at the time a swap-backed vm_page_t is freed, we will never - * see a vm_page with assigned swap here. + * Load pages from backing store. */ static int default_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind, int *rahead) { + /* + * Since an OBJT_DEFAULT object is converted to OBJT_SWAP by the first + * call to the putpages method, this function will never be called on + * a vm_page with assigned swap. + */ return (VM_PAGER_FAIL); } /* - * Store pages to backing store. We should assign swap and initiate - * I/O. We do not actually convert the object to OBJT_SWAP here. The - * object will be converted when the written-out vm_page_t is moved from the - * cache to the free list. + * Store pages to backing store. */ static void default_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags, int *rtvals) { + /* The swap pager will convert the object to OBJT_SWAP. */ swappagerops.pgo_putpages(object, m, count, flags, rtvals); } /* - * Tell us whether the backing store for the requested (object,index) is - * synchronized. i.e. tell us whether we can throw the page away and - * reload it later. So, for example, if we are in the process of writing - * the page to its backing store, or if no backing store has been assigned, - * it is not yet synchronized. - * - * It is possible to have fully-synchronized swap assigned without the - * object having been converted. We just call swap_pager_haspage() to - * deal with it since it must already deal with it plus deal with swap - * meta-data structures. + * Tell us whether the requested (object,index) is available from the object's + * backing store. */ static boolean_t -default_pager_haspage(object, pindex, before, after) - vm_object_t object; - vm_pindex_t pindex; - int *before; - int *after; +default_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, + int *after) { - return FALSE; + + /* An OBJT_DEFAULT object has no backing store. */ + return (FALSE); } |