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Document flags of vm_page allocation functions.

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Reviewed by:	alc
This commit is contained in:
Gleb Smirnoff 2014-12-22 08:59:44 +00:00
parent 851cc4c0c3
commit 89fc8bdbb6
1 changed files with 25 additions and 12 deletions
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37
sys/vm/vm_page.h
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@ -376,22 +376,35 @@ extern long first_page; /* first physical page number */
vm_page_t PHYS_TO_VM_PAGE(vm_paddr_t pa);
/* page allocation classes: */
/*
* Page allocation parameters for vm_page for the functions
* vm_page_alloc(), vm_page_grab(), vm_page_alloc_contig() and
* vm_page_alloc_freelist(). Some functions support only a subset
* of the flags, and ignore others, see the flags legend.
*
* Bits 0 - 1 define class.
* Bits 2 - 15 dedicated for flags.
* Legend:
* (a) - vm_page_alloc() supports the flag.
* (c) - vm_page_alloc_contig() supports the flag.
* (f) - vm_page_alloc_freelist() supports the flag.
* (g) - vm_page_grab() supports the flag.
* Bits above 15 define the count of additional pages that the caller
* intends to allocate.
*/
#define VM_ALLOC_NORMAL 0
#define VM_ALLOC_INTERRUPT 1
#define VM_ALLOC_SYSTEM 2
#define VM_ALLOC_CLASS_MASK 3
/* page allocation flags: */
#define VM_ALLOC_WIRED 0x0020 /* non pageable */
#define VM_ALLOC_ZERO 0x0040 /* Try to obtain a zeroed page */
#define VM_ALLOC_NOOBJ 0x0100 /* No associated object */
#define VM_ALLOC_NOBUSY 0x0200 /* Do not busy the page */
#define VM_ALLOC_IFCACHED 0x0400 /* Fail if the page is not cached */
#define VM_ALLOC_IFNOTCACHED 0x0800 /* Fail if the page is cached */
#define VM_ALLOC_IGN_SBUSY 0x1000 /* vm_page_grab() only */
#define VM_ALLOC_NODUMP 0x2000 /* don't include in dump */
#define VM_ALLOC_SBUSY 0x4000 /* Shared busy the page */
#define VM_ALLOC_WIRED 0x0020 /* (acfg) Allocate non pageable page */
#define VM_ALLOC_ZERO 0x0040 /* (acfg) Try to obtain a zeroed page */
#define VM_ALLOC_NOOBJ 0x0100 /* (acg) No associated object */
#define VM_ALLOC_NOBUSY 0x0200 /* (acg) Do not busy the page */
#define VM_ALLOC_IFCACHED 0x0400 /* (ag) Fail if page is not cached */
#define VM_ALLOC_IFNOTCACHED 0x0800 /* (ag) Fail if page is cached */
#define VM_ALLOC_IGN_SBUSY 0x1000 /* (g) Ignore shared busy flag */
#define VM_ALLOC_NODUMP 0x2000 /* (ag) don't include in dump */
#define VM_ALLOC_SBUSY 0x4000 /* (acg) Shared busy the page */
#define VM_ALLOC_COUNT_SHIFT 16
#define VM_ALLOC_COUNT(count) ((count) << VM_ALLOC_COUNT_SHIFT)