Differential D23016 Diff 66524 head/share/man/man9/zone.9

Changeset View

Standalone View

head/share/man/man9/zone.9

	Show All 19 Lines
	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)			.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT			.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY			.\" 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			.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	.\" SUCH DAMAGE.			.\" SUCH DAMAGE.
	.\"			.\"
	.\" $FreeBSD$			.\" $FreeBSD$
	.\"			.\"
	.Dd November 22, 2019			.Dd January 8, 2020
	.Dt UMA 9			.Dt UMA 9
	.Os			.Os
	.Sh NAME			.Sh NAME
	.Nm UMA			.Nm UMA
	.Nd general-purpose kernel object allocator			.Nd general-purpose kernel object allocator
	.Sh SYNOPSIS			.Sh SYNOPSIS
	.In sys/param.h			.In sys/param.h
	.In sys/queue.h			.In sys/queue.h
	▲ Show 20 Lines • Show All 250 Lines • ▼ Show 20 Lines
	.Ed			.Ed
	Note that			Note that
	.Dv M_ZERO			.Dv M_ZERO
	cannot be used when allocating items from a PCPU zone.			cannot be used when allocating items from a PCPU zone.
	To obtain zeroed memory from a PCPU zone, use the			To obtain zeroed memory from a PCPU zone, use the
	.Fn uma_zalloc_pcpu			.Fn uma_zalloc_pcpu
	function and its variants instead, and pass			function and its variants instead, and pass
	.Dv M_ZERO .			.Dv M_ZERO .
	.It Dv UMA_ZONE_OFFPAGE			.It Dv UMA_ZONE_NOTOUCH
	By default book-keeping of items within a slab is done in the slab page itself.			The UMA subsystem may not directly touch (i.e. read or write) the slab memory.
	This flag explicitly tells subsystem that book-keeping structure should be			Otherwise, by default, book-keeping of items within a slab may be done in the
	allocated separately from special internal zone.			slab page itself, and
	This flag requires either			.Dv INVARIANTS
	.Dv UMA_ZONE_VTOSLAB			kernels may also do use-after-free checking by accessing the slab memory.
	or
	.Dv UMA_ZONE_HASH ,
	since subsystem requires a mechanism to find a book-keeping structure
	to an item being freed.
	The subsystem may choose to prefer offpage book-keeping for certain zones
	implicitly.
	.It Dv UMA_ZONE_ZINIT			.It Dv UMA_ZONE_ZINIT
	The zone will have its			The zone will have its
	.Ft uma_init			.Ft uma_init
	method set to internal method that initializes a new allocated slab			method set to internal method that initializes a new allocated slab
	to all zeros.			to all zeros.
	Do not mistake			Do not mistake
	.Ft uma_init			.Ft uma_init
	method with			method with
	.Ft uma_ctor .			.Ft uma_ctor .
	A zone with			A zone with
	.Dv UMA_ZONE_ZINIT			.Dv UMA_ZONE_ZINIT
	flag would not return zeroed memory on every			flag would not return zeroed memory on every
	.Fn uma_zalloc .			.Fn uma_zalloc .
	.It Dv UMA_ZONE_HASH			.It Dv UMA_ZONE_NOTPAGE
	The zone should use an internal hash table to find slab book-keeping			An allocator function will be supplied with
	structure where an allocation being freed belongs to.			.Fn uma_zone_set_allocf
	.It Dv UMA_ZONE_VTOSLAB			and the memory that it returns may not be kernel virtual memory backed by VM
	The zone should use special field of			pages in the page array.
	.Vt vm_page_t
	to find slab book-keeping structure where an allocation being freed belongs to.
	.It Dv UMA_ZONE_MALLOC			.It Dv UMA_ZONE_MALLOC
	The zone is for the			The zone is for the
	.Xr malloc 9			.Xr malloc 9
	subsystem.			subsystem.
	.It Dv UMA_ZONE_VM			.It Dv UMA_ZONE_VM
	The zone is for the VM subsystem.			The zone is for the VM subsystem.
	.It Dv UMA_ZONE_NUMA			.It Dv UMA_ZONE_NUMA
	The zone should use a first-touch NUMA policy rather than the round-robin			The zone should use a first-touch NUMA policy rather than the round-robin
	▲ Show 20 Lines • Show All 272 Lines • Show Last 20 Lines