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

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    .\" $Log:       memory_object_set_attributes.man,v $
    .\" Revision 2.5  93/05/10  19:34:03  rvb
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    .TH memory_object_set_attributes 2 12/19/89
    .CM 4
    .SH NAME
    .nf
    memory_object_set_attributes  \-  indicate how kernel should handle object
    .SH SYNOPSIS
    .nf
    .ft B
    #include <mach.h>
    
    .nf
    .ft B
    kern_return_t memory_object_set_attributes(memory_control,
                                    object_ready, may_cache_object,
                                    copy_strategy)
            mach_port_t
                            memory_control;
            boolean_t       object_ready;
            boolean_t       may_cache_object;
            memory_object_copy_strategy_t
                            copy_strategy;
    
    
    .fi
    .ft P
    .SH DESCRIPTION
    
    .B memory_object_set_attributes
    controls how the the memory object.  The kernel will only make data or unlock requests when
    the ready attribute is asserted.  If the caching attribute is asserted, the
    kernel is permitted (and encouraged) to maintain
    cached data for this memory object even after no virtual address space
    contains this data.
    
    There are three possible caching strategies: 
    .B MEMORY_OBJECT_COPY_NONE
    which specifies that nothing special should be done when data in the
    object is copied; 
    .B MEMORY_OBJECT_COPY_CALL
    which specifies that the
    memory manager should be notified via a 
    .B memory_object_copy
    call before
    any part of the object is copied; and 
    .B MEMORY_OBJECT_COPY_DELAY
    which
    guarantees that the memory manager does not externally modify the data
    so that the kernel can use its normal copy-on-write algorithms.  
    .B MEMORY_OBJECT_COPY_DELAY
    is the strategy most commonly used.
    
    .SH ARGUMENTS
    .TP 15
    .B
    memory_control
    The port, provided by the kernel 
    in a 
   .B memory_object_init
   call, to which cache management requests may be issued.
   .TP 15
   .B
   object_ready
   When set, the kernel may issue new data and unlock requests on the
   associated memory object.
   .TP 15
   .B
   may_cache_object
   If set, the kernel may keep data 
   associated with this
   memory object, even after virtual memory references to it are gone.
   .TP 15
   .B
   copy_strategy
   How the kernel should copy regions of the associated
   memory object.
   
   .SH DIAGNOSTICS
   .TP 25
   KERN_SUCCESS
   This routine does not receive a reply message (and consequently
   has no return value), so only message transmission errors apply.
   
   .SH SEE ALSO
   .B memory_object_init, memory_object_copy, memory_object_attributes
   

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