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-rw-r--r--block/Kconfig13
-rw-r--r--block/Kconfig.iosched1
-rw-r--r--block/Makefile1
-rw-r--r--block/blk-cgroup.c177
-rw-r--r--block/blk-cgroup.h58
-rw-r--r--include/linux/cgroup_subsys.h6
-rw-r--r--include/linux/iocontext.h4
7 files changed, 260 insertions, 0 deletions
diff --git a/block/Kconfig b/block/Kconfig
index 9be0b56..6ba1a8e 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -77,6 +77,19 @@ config BLK_DEV_INTEGRITY
T10/SCSI Data Integrity Field or the T13/ATA External Path
Protection. If in doubt, say N.
+config BLK_CGROUP
+ bool
+ depends on CGROUPS
+ default n
+ ---help---
+ Generic block IO controller cgroup interface. This is the common
+ cgroup interface which should be used by various IO controlling
+ policies.
+
+ Currently, CFQ IO scheduler uses it to recognize task groups and
+ control disk bandwidth allocation (proportional time slice allocation)
+ to such task groups.
+
endif # BLOCK
config BLOCK_COMPAT
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 8bd1051..be0280d 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -23,6 +23,7 @@ config IOSCHED_DEADLINE
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
+ select BLK_CGROUP
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
diff --git a/block/Makefile b/block/Makefile
index 7914108..cb2d515 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
blk-iopoll.o ioctl.o genhd.o scsi_ioctl.o
obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
+obj-$(CONFIG_BLK_CGROUP) += blk-cgroup.o
obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
new file mode 100644
index 0000000..4f6afd7
--- /dev/null
+++ b/block/blk-cgroup.c
@@ -0,0 +1,177 @@
+/*
+ * Common Block IO controller cgroup interface
+ *
+ * Based on ideas and code from CFQ, CFS and BFQ:
+ * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
+ *
+ * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
+ * Paolo Valente <paolo.valente@unimore.it>
+ *
+ * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
+ * Nauman Rafique <nauman@google.com>
+ */
+#include <linux/ioprio.h>
+#include "blk-cgroup.h"
+
+struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
+
+struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
+{
+ return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
+ struct blkio_cgroup, css);
+}
+
+void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
+ struct blkio_group *blkg, void *key)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&blkcg->lock, flags);
+ rcu_assign_pointer(blkg->key, key);
+ hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
+ spin_unlock_irqrestore(&blkcg->lock, flags);
+}
+
+int blkiocg_del_blkio_group(struct blkio_group *blkg)
+{
+ /* Implemented later */
+ return 0;
+}
+
+/* called under rcu_read_lock(). */
+struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
+{
+ struct blkio_group *blkg;
+ struct hlist_node *n;
+ void *__key;
+
+ hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
+ __key = blkg->key;
+ if (__key == key)
+ return blkg;
+ }
+
+ return NULL;
+}
+
+#define SHOW_FUNCTION(__VAR) \
+static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \
+ struct cftype *cftype) \
+{ \
+ struct blkio_cgroup *blkcg; \
+ \
+ blkcg = cgroup_to_blkio_cgroup(cgroup); \
+ return (u64)blkcg->__VAR; \
+}
+
+SHOW_FUNCTION(weight);
+#undef SHOW_FUNCTION
+
+static int
+blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
+{
+ struct blkio_cgroup *blkcg;
+
+ if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
+ return -EINVAL;
+
+ blkcg = cgroup_to_blkio_cgroup(cgroup);
+ blkcg->weight = (unsigned int)val;
+ return 0;
+}
+
+struct cftype blkio_files[] = {
+ {
+ .name = "weight",
+ .read_u64 = blkiocg_weight_read,
+ .write_u64 = blkiocg_weight_write,
+ },
+};
+
+static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
+{
+ return cgroup_add_files(cgroup, subsys, blkio_files,
+ ARRAY_SIZE(blkio_files));
+}
+
+static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
+
+ free_css_id(&blkio_subsys, &blkcg->css);
+ kfree(blkcg);
+}
+
+static struct cgroup_subsys_state *
+blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
+{
+ struct blkio_cgroup *blkcg, *parent_blkcg;
+
+ if (!cgroup->parent) {
+ blkcg = &blkio_root_cgroup;
+ goto done;
+ }
+
+ /* Currently we do not support hierarchy deeper than two level (0,1) */
+ parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent);
+ if (css_depth(&parent_blkcg->css) > 0)
+ return ERR_PTR(-EINVAL);
+
+ blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
+ if (!blkcg)
+ return ERR_PTR(-ENOMEM);
+
+ blkcg->weight = BLKIO_WEIGHT_DEFAULT;
+done:
+ spin_lock_init(&blkcg->lock);
+ INIT_HLIST_HEAD(&blkcg->blkg_list);
+
+ return &blkcg->css;
+}
+
+/*
+ * We cannot support shared io contexts, as we have no mean to support
+ * two tasks with the same ioc in two different groups without major rework
+ * of the main cic data structures. For now we allow a task to change
+ * its cgroup only if it's the only owner of its ioc.
+ */
+static int blkiocg_can_attach(struct cgroup_subsys *subsys,
+ struct cgroup *cgroup, struct task_struct *tsk,
+ bool threadgroup)
+{
+ struct io_context *ioc;
+ int ret = 0;
+
+ /* task_lock() is needed to avoid races with exit_io_context() */
+ task_lock(tsk);
+ ioc = tsk->io_context;
+ if (ioc && atomic_read(&ioc->nr_tasks) > 1)
+ ret = -EINVAL;
+ task_unlock(tsk);
+
+ return ret;
+}
+
+static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup,
+ struct cgroup *prev, struct task_struct *tsk,
+ bool threadgroup)
+{
+ struct io_context *ioc;
+
+ task_lock(tsk);
+ ioc = tsk->io_context;
+ if (ioc)
+ ioc->cgroup_changed = 1;
+ task_unlock(tsk);
+}
+
+struct cgroup_subsys blkio_subsys = {
+ .name = "blkio",
+ .create = blkiocg_create,
+ .can_attach = blkiocg_can_attach,
+ .attach = blkiocg_attach,
+ .destroy = blkiocg_destroy,
+ .populate = blkiocg_populate,
+ .subsys_id = blkio_subsys_id,
+ .use_id = 1,
+};
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
new file mode 100644
index 0000000..ba5703f
--- /dev/null
+++ b/block/blk-cgroup.h
@@ -0,0 +1,58 @@
+#ifndef _BLK_CGROUP_H
+#define _BLK_CGROUP_H
+/*
+ * Common Block IO controller cgroup interface
+ *
+ * Based on ideas and code from CFQ, CFS and BFQ:
+ * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
+ *
+ * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
+ * Paolo Valente <paolo.valente@unimore.it>
+ *
+ * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
+ * Nauman Rafique <nauman@google.com>
+ */
+
+#include <linux/cgroup.h>
+
+struct blkio_cgroup {
+ struct cgroup_subsys_state css;
+ unsigned int weight;
+ spinlock_t lock;
+ struct hlist_head blkg_list;
+};
+
+struct blkio_group {
+ /* An rcu protected unique identifier for the group */
+ void *key;
+ struct hlist_node blkcg_node;
+};
+
+#define BLKIO_WEIGHT_MIN 100
+#define BLKIO_WEIGHT_MAX 1000
+#define BLKIO_WEIGHT_DEFAULT 500
+
+#ifdef CONFIG_BLK_CGROUP
+extern struct blkio_cgroup blkio_root_cgroup;
+extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
+extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
+ struct blkio_group *blkg, void *key);
+extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
+extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
+ void *key);
+#else
+static inline struct blkio_cgroup *
+cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
+
+static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
+ struct blkio_group *blkg, void *key)
+{
+}
+
+static inline int
+blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
+
+static inline struct blkio_group *
+blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
+#endif
+#endif /* _BLK_CGROUP_H */
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 9c8d31b..ccefff0 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -60,3 +60,9 @@ SUBSYS(net_cls)
#endif
/* */
+
+#ifdef CONFIG_BLK_CGROUP
+SUBSYS(blkio)
+#endif
+
+/* */
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index eb73632..d61b0b8 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -68,6 +68,10 @@ struct io_context {
unsigned short ioprio;
unsigned short ioprio_changed;
+#ifdef CONFIG_BLK_CGROUP
+ unsigned short cgroup_changed;
+#endif
+
/*
* For request batching
*/