[PATCH] VM: kswapd should not do blocking memory allocations

Trond Myklebust
2010-08-18T19:04:29Z

From: Trond Myklebust <Trond.Myklebust@netapp.com>

Allowing kswapd to do GFP_KERNEL memory allocations (or any blocking memory
allocations) is wrong and can cause deadlocks in try_to_release_page(), as
the filesystem believes it is safe to allocate new memory and block,
whereas kswapd is there specifically to clear a low-memory situation...

Set the gfp_mask to GFP_IOFS instead.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---

mm/vmscan.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index ec5ddcc..716dd16 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2095,7 +2095,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
unsigned long total_scanned;
struct reclaim_state *reclaim_state = current->reclaim_state;
struct scan_control sc = {
- .gfp_mask = GFP_KERNEL,
+ .gfp_mask = GFP_IOFS,
.may_unmap = 1,
.may_swap = 1,
/*