mm: call into direct reclaim without PF_MEMALLOC set

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

PF_MEMALLOC keeps direct reclaim from recursing into itself, I noticed this
call to try_to_free_pages didn't set it thus opening the floodgates.

/me wonders why this never triggered...

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 fs/buffer.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

Index: linux-2.6-git/fs/buffer.c
===================================================================
--- linux-2.6-git.orig/fs/buffer.c	2006-11-15 20:14:58.000000000 +0100
+++ linux-2.6-git/fs/buffer.c	2006-11-15 20:19:22.000000000 +0100
@@ -360,8 +360,18 @@ static void free_more_memory(void)
 
 	for_each_online_pgdat(pgdat) {
 		zones = pgdat->node_zonelists[gfp_zone(GFP_NOFS)].zones;
-		if (*zones)
+		if (*zones) {
+			struct task_struct *p = current;
+			struct reclaim_state reclaim_state;
+			reclaim_state.reclaim_slab = 0;
+			p->flags |= PF_MEMALLOC;
+			p->reclaim_state = &reclaim_state;
+
 			try_to_free_pages(zones, GFP_NOFS);
+
+			p->reclaim_state = NULL;
+			p->flags &= ~PF_MEMALLOC;
+		}
 	}
 }
 


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