Messages in this thread Patch in this message | | | Subject | [patch 03/39] add swap cache mapping comment | From | blaisorblade@yahoo ... | Date | Fri, 12 Aug 2005 20:21:02 +0200 |
| |
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Add some more comments about page->mapping and swapper_space, explaining their (historical and current) relationship. Such material can be extracted from the old GIT history (which I used for reference), but having it in the source is more useful.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> ---
linux-2.6.git-paolo/./mm/swap_state.c | 5 +++++ 1 files changed, 5 insertions(+)
diff -puN ./mm/swap_state.c~swap-cache-mapping-comment ./mm/swap_state.c --- linux-2.6.git/./mm/swap_state.c~swap-cache-mapping-comment 2005-08-11 11:12:57.000000000 +0200 +++ linux-2.6.git-paolo/./mm/swap_state.c 2005-08-11 11:12:57.000000000 +0200 @@ -21,6 +21,11 @@ * swapper_space is a fiction, retained to simplify the path through * vmscan's shrink_list, to make sync_page look nicer, and to allow * future use of radix_tree tags in the swap cache. + * + * In 2.4 and until 2.6.6 pages in the swap cache also had page->mapping == + * &swapper_space (this was the definition of PageSwapCache), but this is no + * more true. Instead, we use page->flags for that, and page->mapping is + * *ignored* here. However, also take a look at page_mapping(). */ static struct address_space_operations swap_aops = { .writepage = swap_writepage, _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |