[patch 5/7] mm: throttle writeout with cpuset awareness

[David Rientjes <rientjes@google.com>]

From: Christoph Lameter <cl@linux-foundation.org>

This bases the VM throttling from the reclaim path on the dirty ratio of
the cpuset.  Note that a cpuset is only effective if shrink_zone is called
from direct reclaim.

kswapd has a cpuset context that includes the whole machine.  VM
throttling will only work during synchrononous reclaim and not from
kswapd.

Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Menage <menage@google.com>
Cc: Derek Fults <dfults@sgi.com>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 include/linux/writeback.h |    2 +-
 mm/page-writeback.c       |    4 ++--
 mm/vmscan.c               |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -114,7 +114,7 @@ static inline void inode_sync_wait(struct inode *inode)
 int wakeup_pdflush(long nr_pages, nodemask_t *nodes);
 void laptop_io_completion(void);
 void laptop_sync_completion(void);
-void throttle_vm_writeout(gfp_t gfp_mask);
+void throttle_vm_writeout(nodemask_t *nodes, gfp_t gfp_mask);
 
 /* These are exported to sysctl. */
 extern int dirty_background_ratio;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -638,12 +638,12 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
 }
 EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);
 
-void throttle_vm_writeout(gfp_t gfp_mask)
+void throttle_vm_writeout(nodemask_t *nodes, gfp_t gfp_mask)
 {
 	struct dirty_limits dl;
 
         for ( ; ; ) {
-		get_dirty_limits(&dl, NULL, &node_states[N_HIGH_MEMORY]);
+		get_dirty_limits(&dl, NULL, nodes);
 
 		/*
 		 * Boost the allowable dirty threshold a bit for page
diff --git a/mm/vmscan.c b/mm/vmscan.c
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1466,7 +1466,7 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
 	else if (!scan_global_lru(sc))
 		shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
 
-	throttle_vm_writeout(sc->gfp_mask);
+	throttle_vm_writeout(&cpuset_current_mems_allowed, sc->gfp_mask);
 	return nr_reclaimed;
 }