mm: dirty balancing for tasks

Based on ideas of Andrew:
  http://marc.info/?l=linux-kernel&m=102912915020543&w=2

Scale the bdi dirty limit inversly with the tasks dirty rate.
This makes heavy writers have a lower dirty limit than the occasional writer.

Andrea proposed something similar:
  http://lwn.net/Articles/152277/

The main disadvantage to his patch is that he uses an unrelated quantity to
measure time, which leaves him with a workload dependant tunable. Other than
that the two approaches appear quite similar.

[akpm@linux-foundation.org: fix warning]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 513bc3e489f0..3a619f57a2b2 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -171,6 +171,7 @@ extern struct group_info init_groups;
                 [PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID),           \
                 [PIDTYPE_SID]  = INIT_PID_LINK(PIDTYPE_SID),            \
         },                                                              \
+        .dirties = INIT_PROP_LOCAL_SINGLE(dirties),                     \
         INIT_TRACE_IRQFLAGS                                             \
         INIT_LOCKDEP                                                    \
 }