Copyright (C) 2001 Chad David <firstname.lastname@example.org>. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice(s), this list of conditions and the following disclaimer as the first lines of this file unmodified other than the possible addition of one or more copyright notices. 2. Redistributions in binary for...
NAMEvm_page_aflag_clear , vm_page_aflag_set , vm_page_reference - change page atomic flags
SYNOPSISIn sys/param.h In vm/vm.h In vm/vm_page.h Ft void Fn vm_page_aflag_clear vm_page_t m uint8_t bits Ft void Fn vm_page_aflag_set vm_page_t m uint8_t bits Ft void Fn vm_page_reference vm_page_t m
DESCRIPTIONThe Fn vm_page_aflag_clear atomically clears the specified bits on the page's aflags
The Fn vm_page_aflag_set atomically sets the specified bits on the page's aflags
The Fn vm_page_reference m call is the same as
Lp and is the recommended way to mark the page as referenced from third-party kernel modules.vm_page_aflag_set(m, PGA_REFERENCED);
These functions neither block nor require any locks to be held around the calls for correctness.
The functions arguments are:
- Fa m
- The page whose aflags are updated.
- Fa bits
- The bits that are set or cleared on the page's flags.
The following aflags can be set or cleared:
- Fa PGA_REFERENCED
- The bit may be set to indicate that the page has been recently accessed. For instance, pmap(9) sets this bit to reflect the accessed attribute of the page mapping typically updated by processor's memory management unit on the page access.
- Fa PGA_WRITEABLE
- A writeable mapping for the page may exist.
Both PGA_REFERENCED and PGA_WRITEABLE bits are only valid for the managed pages.