From: Nikita Danilov <Nikita@Namesys.COM>
shrink_list() checks PageSwapCache() before calling add_to_swap(), this
means that anonymous page that is going to be added to the swap right
now these checks return false and:
(*) it will be unaccounted for in nr_mapped, and
(*) it won't be written to the swap if gfp_flags include __GFP_IO but
not __GFP_FS.
(Both will happen only on the next round of scanning.)
Patch below just moves may_enter_fs initialization down. I am not sure
about (*nr_mapped) increase though.
---
mm/vmscan.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff -puN mm/vmscan.c~shrink_list-swapcache-check-fix mm/vmscan.c
--- 25/mm/vmscan.c~shrink_list-swapcache-check-fix 2004-02-02 22:45:50.000000000 -0800
+++ 25-akpm/mm/vmscan.c 2004-02-02 22:45:50.000000000 -0800
@@ -274,8 +274,6 @@ shrink_list(struct list_head *page_list,
(*nr_mapped)++;
BUG_ON(PageActive(page));
- may_enter_fs = (gfp_mask & __GFP_FS) ||
- (PageSwapCache(page) && (gfp_mask & __GFP_IO));
if (PageWriteback(page))
goto keep_locked;
@@ -306,6 +304,9 @@ shrink_list(struct list_head *page_list,
}
#endif /* CONFIG_SWAP */
+ may_enter_fs = (gfp_mask & __GFP_FS) ||
+ (PageSwapCache(page) && (gfp_mask & __GFP_IO));
+
/*
* The page is mapped into the page tables of one or more
* processes. Try to unmap it here.
_