diff options
| -rw-r--r-- | share/man/man9/vm_page_alloc.9 | 49 | ||||
| -rw-r--r-- | sys/vm/vm_page.c | 9 |
2 files changed, 35 insertions, 23 deletions
diff --git a/share/man/man9/vm_page_alloc.9 b/share/man/man9/vm_page_alloc.9 index 81070d6..4497e48 100644 --- a/share/man/man9/vm_page_alloc.9 +++ b/share/man/man9/vm_page_alloc.9 @@ -26,7 +26,7 @@ .\" .\" $FreeBSD$ .\" -.Dd February 27, 2010 +.Dd July 3, 2010 .Dt VM_PAGE_ALLOC 9 .Os .Sh NAME @@ -38,7 +38,7 @@ .In vm/vm.h .In vm/vm_page.h .Ft vm_page_t -.Fn vm_page_alloc "vm_object_t object" "vm_pindex_t pindex" "int page_req" +.Fn vm_page_alloc "vm_object_t object" "vm_pindex_t pindex" "int req" .Sh DESCRIPTION The .Fn vm_page_alloc @@ -51,16 +51,15 @@ It is assumed that a page has not already been allocated at The page returned is inserted into the object, unless .Dv VM_ALLOC_NOOBJ is specified in the -.Fa page_req , -but is not inserted into a pmap. -The page may exists in the vm object cache, in which case it will +.Fa req . +The page may exist in the vm object cache, in which case it will be reactivated instead, moving from the cache into the object page list. .Pp .Fn vm_page_alloc will not sleep. .Pp Its arguments are: -.Bl -tag -width ".Fa page_req" +.Bl -tag -width ".Fa object" .It Fa object The VM object to allocate the page for. The @@ -70,40 +69,48 @@ must be locked if is not specified. .It Fa pindex The index into the object at which the page should be inserted. -.It Fa page_req -A flag indicating how the page should be allocated. +.It Fa req +The bitwise-inclusive OR of a class and any optional flags indicating +how the page should be allocated. +.Pp +Exactly one of the following classes must be specified: .Bl -tag -width ".Dv VM_ALLOC_INTERRUPT" .It Dv VM_ALLOC_NORMAL The page should be allocated with no special treatment. .It Dv VM_ALLOC_SYSTEM -The page can be allocated if the cache queue is empty and the free +The page can be allocated if the cache is empty and the free page count is above the interrupt reserved water mark. -If -.Dv VM_ALLOC_INTERRUPT -is set, the page can be allocated as long as the free page count is -greater than zero. This flag should be used only when the system really needs the page. .It Dv VM_ALLOC_INTERRUPT .Fn vm_page_alloc -is being called during an interrupt and therefore the cache cannot -be accessed. -The page will only be returned successfully if the free count is greater +is being called during an interrupt. +A page will be returned successfully if the free page count is greater than zero. +.El +.Pp +The optional flags are: +.Bl -tag -width ".Dv VM_ALLOC_IFNOTCACHED" .It Dv VM_ALLOC_ZERO Indicate a preference for a pre-zeroed page. -There is no guarantee that the page thus returned will be zeroed, but -it will be marked by +There is no guarantee that the returned page will be zeroed, but it +will have the .Dv PG_ZERO -flag if it is zeroed. +flag set if it is zeroed. .It Dv VM_ALLOC_NOOBJ Do not associate the allocated page with a vm object. The .Fa object argument is ignored. .It Dv VM_ALLOC_NOBUSY -The page returned will not be busied. +The returned page will not have the +.Dv VPO_BUSY +flag set. .It Dv VM_ALLOC_WIRED -The returned page is wired. +The returned page will be wired. +.It Dv VM_ALLOC_IFCACHED +Allocate the page only if it is cached. +Otherwise, return +.Dv NULL . .It Dv VM_ALLOC_IFNOTCACHED Only allocate the page if it is not cached in the .Fa object . diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c index b1354e9..fc9fdd4 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -1144,14 +1144,19 @@ vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart, * Allocate and return a memory cell associated * with this VM object/offset pair. * - * page_req classes: + * The caller must always specify an allocation class. + * + * allocation classes: * VM_ALLOC_NORMAL normal process request * VM_ALLOC_SYSTEM system *really* needs a page * VM_ALLOC_INTERRUPT interrupt time request - * VM_ALLOC_ZERO zero page + * + * optional allocation flags: + * VM_ALLOC_ZERO prefer a zeroed page * VM_ALLOC_WIRED wire the allocated page * VM_ALLOC_NOOBJ page is not associated with a vm object * VM_ALLOC_NOBUSY do not set the page busy + * VM_ALLOC_IFCACHED return page only if it is cached * VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page * is cached * |
