projects / apple / xnu.git / blame
| Commit | Line | Data |
|---|---|---|
| 13fec989 A |
1 | <h2>memory_object_data_error</h2> |
| 2 | <hr> | |
| 3 | <p> | |
| 4 | <strong>Function</strong> - An error prevents the supply of previously requested data. | |
| 5 | <h3>SYNOPSIS</h3> | |
| 6 | <pre> | |
| 7 | <strong>kern_return_t memory_object_data_error</strong> | |
| 8 | <strong>(memory_object_control_t</strong> <var>memory_control</var>, | |
| 9 | <strong>vm_offset_t</strong> <var>offset</var>, | |
| 10 | <strong>vm_size_t</strong> <var>size</var>, | |
| 11 | <strong>kern_return_t</strong> <var>reason</var><strong>);</strong> | |
| 12 | </pre> | |
| 13 | <h3>PARAMETERS</h3> | |
| 14 | <dl> | |
| 15 | <p> | |
| 16 | <dt> <var>memory_control</var> | |
| 17 | <dd> | |
| 18 | [in memory-cache-control send right] | |
| 19 | The memory cache control port | |
| 20 | to be used by the memory manager for cache management requests. | |
| 21 | This port is provided by the kernel in a <strong>memory_object_create</strong> call. | |
| 22 | <p> | |
| 23 | <dt> <var>offset</var> | |
| 24 | <dd> | |
| 25 | [in scalar] | |
| 26 | The offset within the memory object, in bytes. | |
| 27 | <p> | |
| 28 | <dt> <var>size</var> | |
| 29 | <dd> | |
| 30 | [in scalar] | |
| 31 | The number of bytes of data (starting at <var>offset</var>). The number | |
| 32 | must convert to an integral number of memory object pages. | |
| 33 | <p> | |
| 34 | <dt> <var>reason</var> | |
| 35 | <dd> | |
| 36 | [in scalar] | |
| 37 | Reason for the error. | |
| 38 | </dl> | |
| 39 | <h3>DESCRIPTION</h3> | |
| 40 | <p> | |
| 41 | The <strong>memory_object_data_error</strong> function indicates that | |
| 42 | the memory manager | |
| 43 | cannot provide the kernel with the data requested for the given region, | |
| 44 | specifying a reason for the error. | |
| 45 | <p> | |
| 46 | When the kernel issues a <strong>memory_object_data_request</strong> call, the memory | |
| 47 | manager can respond with a <strong>memory_object_data_error</strong> | |
| 48 | call to indicate that the | |
| 49 | page cannot be retrieved, and that a memory failure exception should be raised | |
| 50 | in any client threads that are waiting for the page. Clients | |
| 51 | are permitted to catch | |
| 52 | these exceptions and retry their page faults. As a result, this | |
| 53 | call can be used to | |
| 54 | report transient errors as well as permanent ones. A memory manager can use | |
| 55 | this call for both hardware errors (for example, disk failures) and software | |
| 56 | errors (for example, accessing data that does not exist or is protected). | |
| 57 | <h3>NOTES</h3> | |
| 58 | <p> | |
| 59 | If reason has a system code of <var>err_kern</var>, the kernel will substitute | |
| 60 | an error value | |
| 61 | of <strong>KERN_MEMORY_ERROR</strong>. | |
| 62 | <h3>RETURN VALUES</h3> | |
| 63 | <p> | |
| 64 | Only generic errors apply. | |
| 65 | <h3>RELATED INFORMATION</h3> | |
| 66 | <p> | |
| 67 | Functions: | |
| 68 | <a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>, | |
| 69 | <a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>, | |
| 70 | <a href="MO_data_unavailable.html"><strong>memory_object_data_unavailable</strong></a>. |