From: Paolo 'Blaisorblade' Giarrusso <[email protected]>
Seems like on 2.4.9.4 this comment got out of sync ;-)
I'm not completely sure on which basis we don't need any more to do as the
comment suggests, but it seems that when faulting in a second time the same
swap page, can_share_swap_page() returns false, and we do an early COW break,
so there's no need to write-protect the page.
No idea why we don't defer the COW break.
Reference commit from GIT version of BKCVS history:
5ee46c7964de4b1969fc5be036167eb2da0de4e2, BKRev 3c603c81PtWl2I1NnVuphvsItrD1hg
(v2.4.9.3 -> v2.4.9.4).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[email protected]>
---
linux-2.6.git-paolo/mm/swapfile.c | 5 +----
1 files changed, 1 insertion(+), 4 deletions(-)
diff -puN mm/swapfile.c~remove-stale-comment-swap-file mm/swapfile.c
--- linux-2.6.git/mm/swapfile.c~remove-stale-comment-swap-file 2005-08-11 11:13:18.000000000 +0200
+++ linux-2.6.git-paolo/mm/swapfile.c 2005-08-11 11:13:18.000000000 +0200
@@ -388,10 +388,7 @@ void free_swap_and_cache(swp_entry_t ent
}
/*
- * Always set the resulting pte to be nowrite (the same as COW pages
- * after one process has exited). We don't know just how many PTEs will
- * share this swap entry, so be cautious and let do_wp_page work out
- * what to do if a write is requested later.
+ * Since we're swapping it in, we mark it as old.
*
* vma->vm_mm->page_table_lock is held.
*/
_
-
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