| zone.9 (179880) | zone.9 (213910) |
|---|---|
| 1.\"- 2.\" Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright --- 9 unchanged lines hidden (view full) --- 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" | 1.\"- 2.\" Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright --- 9 unchanged lines hidden (view full) --- 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" |
| 26.\" $FreeBSD: head/share/man/man9/zone.9 179880 2008-06-19 18:33:38Z remko $ | 26.\" $FreeBSD: head/share/man/man9/zone.9 213910 2010-10-16 04:14:45Z lstewart $ |
| 27.\" | 27.\" |
| 28.Dd June 19, 2008 | 28.Dd October 9, 2010 |
| 29.Dt ZONE 9 30.Os 31.Sh NAME 32.Nm uma_zcreate , 33.Nm uma_zalloc , 34.Nm uma_zalloc_arg , 35.Nm uma_zfree , 36.Nm uma_zfree_arg , 37.Nm uma_zdestroy , | 29.Dt ZONE 9 30.Os 31.Sh NAME 32.Nm uma_zcreate , 33.Nm uma_zalloc , 34.Nm uma_zalloc_arg , 35.Nm uma_zfree , 36.Nm uma_zfree_arg , 37.Nm uma_zdestroy , |
| 38.Nm uma_zone_set_max | 38.Nm uma_zone_set_max, 39.Nm uma_zone_get_max, 40.Nm uma_zone_get_cur |
| 39.Nd zone allocator 40.Sh SYNOPSIS 41.In sys/param.h 42.In sys/queue.h 43.In vm/uma.h 44.Ft uma_zone_t 45.Fo uma_zcreate 46.Fa "char *name" "int size" --- 7 unchanged lines hidden (view full) --- 54.Ft void 55.Fn uma_zfree "uma_zone_t zone" "void *item" 56.Ft void 57.Fn uma_zfree_arg "uma_zone_t zone" "void *item" "void *arg" 58.Ft void 59.Fn uma_zdestroy "uma_zone_t zone" 60.Ft void 61.Fn uma_zone_set_max "uma_zone_t zone" "int nitems" | 41.Nd zone allocator 42.Sh SYNOPSIS 43.In sys/param.h 44.In sys/queue.h 45.In vm/uma.h 46.Ft uma_zone_t 47.Fo uma_zcreate 48.Fa "char *name" "int size" --- 7 unchanged lines hidden (view full) --- 56.Ft void 57.Fn uma_zfree "uma_zone_t zone" "void *item" 58.Ft void 59.Fn uma_zfree_arg "uma_zone_t zone" "void *item" "void *arg" 60.Ft void 61.Fn uma_zdestroy "uma_zone_t zone" 62.Ft void 63.Fn uma_zone_set_max "uma_zone_t zone" "int nitems" |
| 64.Ft int 65.Fn uma_zone_get_max "uma_zone_t zone" 66.Ft int 67.Fn uma_zone_get_cur "uma_zone_t zone" |
|
| 62.Sh DESCRIPTION 63The zone allocator provides an efficient interface for managing 64dynamically-sized collections of items of similar size. 65The zone allocator can work with preallocated zones as well as with 66runtime-allocated ones, and is therefore available much earlier in the 67boot process than other memory management routines. 68.Pp 69A zone is an extensible collection of items of identical size. --- 95 unchanged lines hidden (view full) --- 165.Fn uma_zdestroy , 166freeing all memory that was allocated for the zone. 167All items allocated from the zone with 168.Fn uma_zalloc 169must have been freed with 170.Fn uma_zfree 171before. 172.Pp | 68.Sh DESCRIPTION 69The zone allocator provides an efficient interface for managing 70dynamically-sized collections of items of similar size. 71The zone allocator can work with preallocated zones as well as with 72runtime-allocated ones, and is therefore available much earlier in the 73boot process than other memory management routines. 74.Pp 75A zone is an extensible collection of items of identical size. --- 95 unchanged lines hidden (view full) --- 171.Fn uma_zdestroy , 172freeing all memory that was allocated for the zone. 173All items allocated from the zone with 174.Fn uma_zalloc 175must have been freed with 176.Fn uma_zfree 177before. 178.Pp |
| 173The purpose of | 179The |
| 174.Fn uma_zone_set_max | 180.Fn uma_zone_set_max |
| 175is to limit the maximum amount of memory that the system can dedicated 176toward the zone specified by the 177.Fa zone 178argument. | 181function limits the number of items 182.Pq and therefore memory 183that can be allocated to 184.Fa zone . |
| 179The 180.Fa nitems | 185The 186.Fa nitems |
| 181argument gives the upper limit of items in the zone. 182This limits the total number of items in the zone which includes: | 187argument specifies the requested upper limit number of items. 188The effective limit may end up being higher than requested, as the 189implementation will round up to ensure all memory pages allocated to the zone 190are utilised to capacity. 191The limit applies to the total number of items in the zone, which includes |
| 183allocated items, free items and free items in the per-cpu caches. 184On systems with more than one CPU it may not be possible to allocate 185the specified number of items even when there is no shortage of memory, 186because all of the remaining free items may be in the caches of the 187other CPUs when the limit is hit. | 192allocated items, free items and free items in the per-cpu caches. 193On systems with more than one CPU it may not be possible to allocate 194the specified number of items even when there is no shortage of memory, 195because all of the remaining free items may be in the caches of the 196other CPUs when the limit is hit. |
| 197.Pp 198The 199.Fn uma_zone_get_max 200function returns the effective upper limit number of items for a zone. 201.Pp 202The 203.Fn uma_zone_get_cur 204function returns the approximate current occupancy of the zone. 205The returned value is approximate because appropriate synchronisation to 206determine an exact value is not performend by the implementation. 207This ensures low overhead at the expense of potentially stale data being used 208in the calculation. |
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| 188.Sh RETURN VALUES 189The 190.Fn uma_zalloc 191function returns a pointer to an item, or 192.Dv NULL 193if the zone ran out of unused items and the allocator was unable to 194enlarge it. 195.Sh SEE ALSO --- 19 unchanged lines hidden --- | 209.Sh RETURN VALUES 210The 211.Fn uma_zalloc 212function returns a pointer to an item, or 213.Dv NULL 214if the zone ran out of unused items and the allocator was unable to 215enlarge it. 216.Sh SEE ALSO --- 19 unchanged lines hidden --- |