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>
diff --git a/kernel/fork.c b/kernel/fork.c
index 3fc3c13..163325a 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -107,6 +107,7 @@
void free_task(struct task_struct *tsk)
{
+ prop_local_destroy_single(&tsk->dirties);
free_thread_info(tsk->stack);
rt_mutex_debug_task_free(tsk);
free_task_struct(tsk);
@@ -163,6 +164,7 @@
{
struct task_struct *tsk;
struct thread_info *ti;
+ int err;
prepare_to_copy(orig);
@@ -178,6 +180,14 @@
*tsk = *orig;
tsk->stack = ti;
+
+ err = prop_local_init_single(&tsk->dirties);
+ if (err) {
+ free_thread_info(ti);
+ free_task_struct(tsk);
+ return NULL;
+ }
+
setup_thread_stack(tsk, orig);
#ifdef CONFIG_CC_STACKPROTECTOR