[PATCH 5/6] cpuset write vm writeout

From: Ethan Solomita
Date: Tue Sep 11 2007 - 21:42:05 EST


Throttle VM writeout in a cpuset aware way

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 <clameter@xxxxxxx>
Acked-by: Ethan Solomita <solo@xxxxxxxxxx>

---

Patch against 2.6.23-rc4-mm1

diff -uprN -X 0/Documentation/dontdiff 4/include/linux/writeback.h 5/include/linux/writeback.h
--- 4/include/linux/writeback.h 2007-09-11 14:49:47.000000000 -0700
+++ 5/include/linux/writeback.h 2007-09-11 14:50:52.000000000 -0700
@@ -94,7 +94,7 @@ static inline void inode_sync_wait(struc
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 -uprN -X 0/Documentation/dontdiff 4/mm/page-writeback.c 5/mm/page-writeback.c
--- 4/mm/page-writeback.c 2007-09-11 14:49:47.000000000 -0700
+++ 5/mm/page-writeback.c 2007-09-11 14:50:52.000000000 -0700
@@ -386,7 +386,7 @@ void balance_dirty_pages_ratelimited_nr(
}
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;

@@ -401,7 +401,7 @@ void throttle_vm_writeout(gfp_t gfp_mask
}

for ( ; ; ) {
- get_dirty_limits(&dl, NULL, &node_online_map);
+ get_dirty_limits(&dl, NULL, nodes);

/*
* Boost the allowable dirty threshold a bit for page
diff -uprN -X 0/Documentation/dontdiff 4/mm/vmscan.c 5/mm/vmscan.c
--- 4/mm/vmscan.c 2007-09-11 14:50:41.000000000 -0700
+++ 5/mm/vmscan.c 2007-09-11 14:50:52.000000000 -0700
@@ -1185,7 +1185,7 @@ static unsigned long shrink_zone(int pri
}
}

- throttle_vm_writeout(sc->gfp_mask);
+ throttle_vm_writeout(&cpuset_current_mems_allowed, sc->gfp_mask);

atomic_dec(&zone->reclaim_in_progress);
return nr_reclaimed;

-
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