[RFC][PATCH 4/9] cgroups: block: cfq: I/O bandwidth controlling subsystem for CGroups based on CFQ

[Vasily Tarasov <vtaras@openvz.org>]

From: Vasily Tarasov <vtaras@openvz.org>

Adds hooks to CFQ code to form proper data structures interconnection.

Signed-off-by: Vasily Tarasov <vtaras@openvz.org>

---

--- linux-2.6.25-rc5-mm1/include/linux/cfqio-cgroup.h.creat-elim	2008-02-15 01:07:29.000000000 -0500
+++ linux-2.6.25-rc5-mm1/include/linux/cfqio-cgroup.h	2008-02-15 01:08:25.000000000 -0500
@@ -36,6 +36,12 @@ struct cfqio_ss_css {
 extern struct cfqio_cgroup_data *
 cfqio_cgrp_findcreate(struct cfqio_ss_css *, struct cfq_data *, gfp_t gfp_mask);
 extern void cfqio_ss_exit_queue(struct cfq_data *);
+
+static inline struct cfqio_ss_css *cfqio_css_by_tsk(struct task_struct *tsk)
+{
+	return container_of(tsk->cgroups->subsys[cfqio_subsys_id],
+						struct cfqio_ss_css, css);
+}
 #else
 static inline struct cfqio_cgroup_data *
 cfqio_cgrp_findcreate(struct cfqio_ss_css *cfqio_ss,
@@ -45,6 +51,11 @@ cfqio_cgrp_findcreate(struct cfqio_ss_cs
 }
 
 extern void cfqio_ss_exit_queue(struct cfq_data *cfqd) { ; }
+
+static inline struct cfqio_ss_css *cfqio_css_by_tsk(struct task_struct *tsk)
+{
+	return NULL;
+}
 #endif /* CONFIG_CGROUP_CFQIO */
 
 static inline void cfqio_init_cfqio_cgroup(struct cfqio_cgroup_data *cfqio_cgrp)
--- linux-2.6.25-rc5-mm1/block/cfq-iosched.c.creat-elim	2008-02-15 01:03:38.000000000 -0500
+++ linux-2.6.25-rc5-mm1/block/cfq-iosched.c	2008-02-15 01:08:25.000000000 -0500
@@ -12,6 +12,8 @@
 #include <linux/rbtree.h>
 #include <linux/ioprio.h>
 #include <linux/cfq-iosched.h>
+#include <linux/cgroup.h>
+#include <linux/cfqio-cgroup.h>
 
 /*
  * tunables
@@ -1256,11 +1258,14 @@ cfq_find_alloc_queue(struct cfq_data *cf
 {
 	struct cfq_queue *cfqq, *new_cfqq = NULL;
 	struct cfq_io_context *cic;
+	struct cfqio_cgroup_data *cfqio_cgrp = NULL;
+	struct cfqio_ss_css *cfqio_css;
 
 retry:
 	cic = cfq_cic_lookup(cfqd, ioc);
 	/* cic always exists here */
 	cfqq = cic_to_cfqq(cic, is_sync);
+	cfqio_css = cfqio_css_by_tsk(current);
 
 	if (!cfqq) {
 		if (new_cfqq) {
@@ -1277,6 +1282,14 @@ retry:
 			new_cfqq = kmem_cache_alloc_node(cfq_pool,
 					gfp_mask | __GFP_NOFAIL | __GFP_ZERO,
 					cfqd->queue->node);
+			if (new_cfqq) {
+				cfqio_cgrp = cfqio_cgrp_findcreate(cfqio_css,
+								cfqd, gfp_mask);
+				if (!cfqio_cgrp) {
+					kmem_cache_free(cfq_pool, new_cfqq);
+					new_cfqq = NULL;
+				}
+			}
 			spin_lock_irq(cfqd->queue->queue_lock);
 			goto retry;
 		} else {
@@ -1285,6 +1298,13 @@ retry:
 					cfqd->queue->node);
 			if (!cfqq)
 				goto out;
+
+			cfqio_cgrp = cfqio_cgrp_findcreate(cfqio_css,
+							cfqd, gfp_mask);
+			if (!cfqio_cgrp) {
+				kmem_cache_free(cfq_pool, cfqq);
+				cfqq = NULL;
+			}
 		}
 
 		RB_CLEAR_NODE(&cfqq->rb_node);
@@ -1298,6 +1318,8 @@ retry:
 
 		cfq_init_prio_data(cfqq, ioc);
 
+		cfqq->cfqio_cgrp = cfqio_cgrp;
+
 		if (is_sync) {
 			if (!cfq_class_idle(cfqq))
 				cfq_mark_cfqq_idle_window(cfqq);
@@ -1990,6 +2012,8 @@ static void cfq_exit_queue(elevator_t *e
 
 	cfq_shutdown_timer_wq(cfqd);
 
+	cfqio_ss_exit_queue(cfqd);
+
 	kfree(cfqd);
 }
 
@@ -2002,6 +2026,9 @@ static void *cfq_init_queue(struct reque
 		return NULL;
 
 	cfqd->service_tree = CFQ_RB_ROOT;
+#ifndef CONFIG_CGROUP_CFQIO
+	cfqio_init_cfqio_cgroup(&cfqd->cfqio_cgroup);
+#endif
 	INIT_LIST_HEAD(&cfqd->cic_list);
 
 	cfqd->queue = q;
@@ -2022,6 +2049,7 @@ static void *cfq_init_queue(struct reque
 	cfqd->cfq_slice[1] = cfq_slice_sync;
 	cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
 	cfqd->cfq_slice_idle = cfq_slice_idle;
+	INIT_LIST_HEAD(&cfqd->act_cfqio_cgrp_head);
 
 	return cfqd;
 }