patch-2.2.3 linux/include/linux/mm.h

• Lines: 75
• Date: Mon Mar 8 15:51:40 1999
• Orig file: v2.2.2/linux/include/linux/mm.h
• Orig date: Wed Jan 20 23:14:06 1999

diff -u --recursive --new-file v2.2.2/linux/include/linux/mm.h linux/include/linux/mm.h
@@ -177,10 +177,12 @@
 			(test_and_clear_bit(PG_swap_cache, &(page)->flags))
 
 /*
- * page->reserved denotes a page which must never be accessed (which
+ * Various page->flags bits:
+ *
+ * PG_reserved is set for a page which must never be accessed (which
  * may not even be present).
  *
- * page->dma is set for those pages which lie in the range of
+ * PG_DMA is set for those pages which lie in the range of
  * physical addresses capable of carrying DMA transfers.
  *
  * Multiple processes may "see" the same page. E.g. for untouched
@@ -204,8 +206,8 @@
  * The following discussion applies only to them.
  *
  * A page may belong to an inode's memory mapping. In this case,
- * page->inode is the inode, and page->offset is the file offset
- * of the page (not necessarily a multiple of PAGE_SIZE).
+ * page->inode is the pointer to the inode, and page->offset is the
+ * file offset of the page (not necessarily a multiple of PAGE_SIZE).
  *
  * A page may have buffers allocated to it. In this case,
  * page->buffers is a circular list of these buffer heads. Else,
@@ -219,7 +221,7 @@
  * fields are also used for freelist management when page->count==0.)
  * There is also a hash table mapping (inode,offset) to the page
  * in memory if present. The lists for this hash table use the fields
- * page->next_hash and page->prev_hash.
+ * page->next_hash and page->pprev_hash.
  *
  * All process pages can do I/O:
  * - inode pages may need to be read from disk,
@@ -227,18 +229,23 @@
  *   to be written to disk,
  * - private pages which have been modified may need to be swapped out
  *   to swap space and (later) to be read back into memory.
- * During disk I/O, page->locked is true. This bit is set before I/O
+ * During disk I/O, PG_locked is used. This bit is set before I/O
  * and reset when I/O completes. page->wait is a wait queue of all
  * tasks waiting for the I/O on this page to complete.
- * page->uptodate tells whether the page's contents is valid.
+ * PG_uptodate tells whether the page's contents is valid.
  * When a read completes, the page becomes uptodate, unless a disk I/O
  * error happened.
- * When a write completes, and page->free_after is true, the page is
+ * When a write completes, and PG_free_after is set, the page is
  * freed without any further delay.
  *
  * For choosing which pages to swap out, inode pages carry a
- * page->referenced bit, which is set any time the system accesses
+ * PG_referenced bit, which is set any time the system accesses
  * that page through the (inode,offset) hash table.
+ *
+ * PG_skip is used on sparc/sparc64 architectures to "skip" certain
+ * parts of the address space.
+ *
+ * PG_error is set to indicate that an I/O error occurred on this page.
  */
 
 extern mem_map_t * mem_map;
@@ -340,11 +347,6 @@
 
 #define GFP_DMA		__GFP_DMA
 
-/*
- * Decide if we should try to do some swapout..
- */
-extern int free_memory_available(void);
-			
 /* vma is the first one with  address < vma->vm_end,
  * and even  address < vma->vm_start. Have to extend vma. */
 static inline int expand_stack(struct vm_area_struct * vma, unsigned long address)