FreeBSD/Linux Kernel Cross Reference
sys/man/vm_machine_attribute.man

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    .\" HISTORY
    .\" $Log:       vm_machine_attribute.man,v $
    .\" Revision 2.5  93/03/18  15:16:47  mrt
    .\"     corrected types
    .\"     [93/03/12  16:55:24  lli]
    .\" 
    .\" Revision 2.4  91/05/14  17:15:44  mrt
    .\"     Correcting copyright
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    .\" Revision 2.3  91/02/14  14:16:18  mrt
    .\"     Changed to new Mach copyright
    .\"     [91/02/12  18:17:15  mrt]
    .\" 
    .\" Revision 2.2  90/08/07  18:47:37  rpd
    .\"     Created.
    .\" 
    .TH vm_machine_attribute 2 3/15/90
    .CM 4
    .SH NAME
    .nf
    vm_machine_attribute  \-  handle machine-specific VM attributes
    .SH SYNOPSIS
    .nf
    .ft B
    #include <mach.h>
    
    .nf
    .ft B
    kern_return_t vm_machine_attribute (task, address, size, attribute, value)
            mach_port_t                              task;
            vm_address_t                     address;
            vm_size_t                        size;
            vm_machine_attribute_t           attribute;
            vm_machine_attribute_val_t      *value;
    
    
    .fi
    .ft P
    .SH ARGUMENTS
    .TP 15
    .B
    task
    The task whose memory is to be affected
    .TP 15
    .B
    address
    Starting address of the memory segment.
    .TP 15
    .B
    size
    Size of the memory segment
    .TP 15
    .B
    attribute
    Attribute type
    .TP 15
    .B
    value
    Pointer to the attribute's value
    
    .SH DESCRIPTION
    
    .B vm_machine_attribute
    specifies machine-specific attributes for a VM mapping, such as cachability,
    migrability, replicability.  This is used on machines that allow the user
    control over the cache (this is the case for MIPS architectures)
    or placement of memory pages as in NUMA architectures (Non-Uniform Memory
    Access time) such as the IBM ACE multiprocessor.
    
    Machine-specific attributes can be consider additions to the
    machine-independent ones such as protection and inheritance,
    but they are not guaranteed to be supported by any given machine.
    Moreover, implementations of Mach on new architectures might find the need
   for new attribute types and or values besides the ones defined in the
   initial implementation.
   
   The types currently defined are
   
   .B MATTR_CACHE
   Controls caching of memory pages
   
   .B MATTR_MIGRATE
   Controls migrability of memory pages
   
   .B MATTR_REPLICATE
   Controls replication of memory pages
   
   Corresponding values, and meaning of a specific call to
   .B vm_machine_attribute
   
   .B MATTR_VAL_ON
   Enables the attribute.  Being enabled is the default
   value for any applicable attribute.
   
   .B MATTR_VAL_OFF
   Disables the attribute, making memory non-cached,
   or non-migratable, or non-replicatable.
   
   .B MATTR_VAL_GET
   Returns the current value of the attribute for the
   memory segment.  If the attribute does not apply
   uniformly to the given range the value returned
   applies to the initial portion of the segment only.
   
   .B MATTR_VAL_CACHE_FLUSH
   Flush the memory pages from the Cache.
   The 
   .B size
   value in this case might be meaningful
   even if not a multiple of the page size, depending
   on the implementation.
   
   .B MATTR_VAL_ICACHE_FLUSH
   Same as above, applied to the Instruction Cache alone.
   
   .B MATTR_VAL_DCACHE_FLUSH
   Same as above, applied to the Data Cache alone.
   
   
   
   .SH DIAGNOSTICS
   .TP 25
   KERN_SUCCESS
   The call succeeded.
   .TP 25
   KERN_INVALID_ARGUMENT
   .B task
   is not a task, or 
   .B address
   and 
   .B size
   do
   not define a valid address range in 
   .B task
   , or 
   .B attribute
   is not a valid
   attribute type, or it is not implemented, or 
   .B value
   is not a permissible
   value for 
   .B attribute
   .
   
   .SH BUGS
   
   The initial implementation (for MIPS) does not provide for inheritance of
   machine attributes.  This might change if/when the IBM ACE code will be
   merged in the mainline.
   
   

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