Changeset 683 for trunk/kernel/mm/mapper.h

Timestamp:

Jan 13, 2021, 12:36:17 AM (3 years ago)

Author:

alain

Message:

All modifications required to support the <tcp_chat> application
including error recovery in case of packet loss.A

File:

• trunk/kernel/mm/mapper.h (modified) (2 diffs)

trunk/kernel/mm/mapper.h

@@ -39 +39 @@
 /*******************************************************************************************
  * This mapper_t object implements the kernel cache for a given VFS file or directory.
- * There is one mapper per file/dir. It is implemented as a three levels radix tree,
- * entirely stored in the same cluster as the inode representing the file/dir.
+ * There is one mapper per file/dir.
+ * - It is implemented as a three levels radix tree, entirely stored in the same cluster
+ *   as the inode representing the file/directory.
  * - The fast retrieval key is the page index in the file.
  *   The ix1_width, ix2_width, ix3_width sub-indexes are configuration parameters.
  * - The leaves are pointers on physical page descriptors, dynamically allocated
- *   in the local cluster.
+ *   in the same cluster as the radix tree.
  * - The mapper is protected by a "remote_rwlock", to support several simultaneous 
  *   "readers", and only one "writer".
@@ -60 +61 @@
  *   buffer, that can be physically located in any cluster.
  * - In the present implementation the cache size for a given file increases on demand,
- *   and the  allocated memory is only released when the mapper/inode is destroyed.
+ *   and the  allocated memory is only released when the inode is destroyed.
+ *
+ * WARNING : This mapper implementation makes the assumption that the PPM page size
+ *           is 4 Kbytes. This code should be modified to support a generic page size,
+ *           defined by the CONFIG_PPM_PAGE_SIZE parameter. 
  ******************************************************************************************/