From 63eb6b93ce725e4c5f38fc85dd703d49465b03cb Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Wed, 19 Nov 2008 15:36:37 -0800 Subject: [PATCH] vmscan: let GFP_NOFS go to swap again In the past, GFP_NOFS (but of course not GFP_NOIO) was allowed to reclaim by writing to swap. That got partially broken in 2.6.23, when may_enter_fs initialization was moved up before the allocation of swap, so its PageSwapCache test was failing the first time around, Fix it by setting may_enter_fs when add_to_swap() succeeds with __GFP_IO. In fact, check __GFP_IO before calling add_to_swap(): allocating swap we're not ready to use just increases disk seeking. Signed-off-by: Hugh Dickins Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index c141b3e7807..f83a7ed5c6c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -623,6 +623,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, * Try to allocate it some swap space here. */ if (PageAnon(page) && !PageSwapCache(page)) { + if (!(sc->gfp_mask & __GFP_IO)) + goto keep_locked; switch (try_to_munlock(page)) { case SWAP_FAIL: /* shouldn't happen */ case SWAP_AGAIN: @@ -634,6 +636,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, } if (!add_to_swap(page, GFP_ATOMIC)) goto activate_locked; + may_enter_fs = 1; } #endif /* CONFIG_SWAP */