Kernel/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2024-12-29 09:13:38 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

blk-cgroup: config options re-arrangement

Browse Source 
This patch fixes few usability and configurability issues.

o All the cgroup based controller options are configurable from
  "Genral Setup/Control Group Support/" menu. blkio is the only exception.
  Hence make this option visible in above menu and make it configurable from
  there to bring it inline with rest of the cgroup based controllers.

o Get rid of CONFIG_DEBUG_CFQ_IOSCHED.

  This option currently does two things.

  - Enable printing of cgroup paths in blktrace
  - Enables CONFIG_DEBUG_BLK_CGROUP, which in turn displays additional stat
    files in cgroup.

  If we are using group scheduling, blktrace data is of not really much use
  if cgroup information is not present. To get this data, currently one has to
  also enable CONFIG_DEBUG_CFQ_IOSCHED, which in turn brings the overhead of
  all the additional debug stat files which is not desired.

  Hence, this patch moves printing of cgroup paths under
  CONFIG_CFQ_GROUP_IOSCHED.

  This allows us to get rid of CONFIG_DEBUG_CFQ_IOSCHED completely. Now all
  the debug stat files are controlled only by CONFIG_DEBUG_BLK_CGROUP which
  can be enabled through config menu.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Divyesh Shah <dpshah@google.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Vivek Goyal 2010-04-26 19:27:56 +02:00 committed by Jens Axboe
parent e5ff082e8a
commit afc24d49c1
7 changed files with 55 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
Documentation/cgroups/blkio-controller.txt
View File

@ -17,6 +17,9 @@ HOWTO
You can do a very simple testing of running two dd threads in two different
cgroups. Here is what you can do.
- Enable Block IO controller
CONFIG_BLK_CGROUP=y
- Enable group scheduling in CFQ
CONFIG_CFQ_GROUP_IOSCHED=y
@ -54,25 +57,17 @@ cgroups. Here is what you can do.
Various user visible config options
===================================
CONFIG_BLK_CGROUP
- Block IO controller.
CONFIG_DEBUG_BLK_CGROUP
- Debug help. Right now some additional stats file show up in cgroup
if this option is enabled.
CONFIG_CFQ_GROUP_IOSCHED
- Enables group scheduling in CFQ. Currently only 1 level of group
creation is allowed.
CONFIG_DEBUG_CFQ_IOSCHED
- Enables some debugging messages in blktrace. Also creates extra
cgroup file blkio.dequeue.
Config options selected automatically
=====================================
These config options are not user visible and are selected/deselected
automatically based on IO scheduler configuration.
CONFIG_BLK_CGROUP
- Block IO controller. Selected by CONFIG_CFQ_GROUP_IOSCHED.
CONFIG_DEBUG_BLK_CGROUP
- Debug help. Selected by CONFIG_DEBUG_CFQ_IOSCHED.
Details of cgroup files
=======================
- blkio.weight
@ -174,13 +169,13 @@ Details of cgroup files
write, sync or async.
- blkio.avg_queue_size
- Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y.
- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
The average queue size for this cgroup over the entire time of this
cgroup's existence. Queue size samples are taken each time one of the
queues of this cgroup gets a timeslice.
- blkio.group_wait_time
- Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y.
- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
This is the amount of time the cgroup had to wait since it became busy
(i.e., went from 0 to 1 request queued) to get a timeslice for one of
its queues. This is different from the io_wait_time which is the
@ -191,7 +186,7 @@ Details of cgroup files
got a timeslice and will not include the current delta.
- blkio.empty_time
- Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y.
- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
This is the amount of time a cgroup spends without any pending
requests when not being served, i.e., it does not include any time
spent idling for one of the queues of the cgroup. This is in
@ -200,7 +195,7 @@ Details of cgroup files
time it had a pending request and will not include the current delta.
- blkio.idle_time
- Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y.
- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
This is the amount of time spent by the IO scheduler idling for a
given cgroup in anticipation of a better request than the exising ones
from other queues/cgroups. This is in nanoseconds. If this is read
@ -209,7 +204,7 @@ Details of cgroup files
the current delta.
- blkio.dequeue
- Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. This
- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y. This
gives the statistics about how many a times a group was dequeued
from service tree of the device. First two fields specify the major
and minor number of the device and third field specifies the number

23
block/Kconfig
View File

@ -77,29 +77,6 @@ config BLK_DEV_INTEGRITY
T10/SCSI Data Integrity Field or the T13/ATA External Path
Protection. If in doubt, say N.
config BLK_CGROUP
tristate "Block cgroup support"
depends on CGROUPS
depends on CFQ_GROUP_IOSCHED
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.
config DEBUG_BLK_CGROUP
bool
depends on BLK_CGROUP
default n
---help---
Enable some debugging help. Currently it stores the cgroup path
in the blk group which can be used by cfq for tracing various
group related activity.
endif # BLOCK
config BLOCK_COMPAT

16
block/Kconfig.iosched
View File

@ -23,7 +23,8 @@ config IOSCHED_DEADLINE
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
select BLK_CGROUP if CFQ_GROUP_IOSCHED
# If BLK_CGROUP is a module, CFQ has to be built as module.
depends on (BLK_CGROUP=m && m) || !BLK_CGROUP || BLK_CGROUP=y
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
@ -33,22 +34,15 @@ config IOSCHED_CFQ
This is the default I/O scheduler.
Note: If BLK_CGROUP=m, then CFQ can be built only as module.
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && CGROUPS
depends on IOSCHED_CFQ && BLK_CGROUP
default n
---help---
Enable group IO scheduling in CFQ.
config DEBUG_CFQ_IOSCHED
bool "Debug CFQ Scheduling"
depends on CFQ_GROUP_IOSCHED
select DEBUG_BLK_CGROUP
default n
---help---
Enable CFQ IO scheduling debugging in CFQ. Currently it makes
blktrace output more verbose.
choice
prompt "Default I/O scheduler"
default DEFAULT_CFQ

2
block/blk-cgroup.c
View File

@ -351,10 +351,8 @@ void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
blkg->blkcg_id = css_id(&blkcg->css);
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
spin_unlock_irqrestore(&blkcg->lock, flags);
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Need to take css reference ? */
cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
#endif
blkg->dev = dev;
}
EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);

14
block/blk-cgroup.h
View File

@ -108,10 +108,8 @@ struct blkio_group {
void *key;
struct hlist_node blkcg_node;
unsigned short blkcg_id;
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Store cgroup path */
char path[128];
#endif
/* The device MKDEV(major, minor), this group has been created for */
dev_t dev;
@ -147,6 +145,11 @@ struct blkio_policy_type {
extern void blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
static inline char *blkg_path(struct blkio_group *blkg)
{
return blkg->path;
}
#else
struct blkio_group {
@ -158,6 +161,8 @@ struct blkio_policy_type {
static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
#endif
#define BLKIO_WEIGHT_MIN 100
@ -165,10 +170,6 @@ static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
#define BLKIO_WEIGHT_DEFAULT 500
#ifdef CONFIG_DEBUG_BLK_CGROUP
static inline char *blkg_path(struct blkio_group *blkg)
{
return blkg->path;
}
void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg);
void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue);
@ -197,7 +198,6 @@ BLKG_FLAG_FNS(idling)
BLKG_FLAG_FNS(empty)
#undef BLKG_FLAG_FNS
#else
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
static inline void blkiocg_update_avg_queue_size_stats(
struct blkio_group *blkg) {}
static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,

2
block/cfq-iosched.c
View File

@ -345,7 +345,7 @@ CFQ_CFQQ_FNS(deep);
CFQ_CFQQ_FNS(wait_busy);
#undef CFQ_CFQQ_FNS
#ifdef CONFIG_DEBUG_CFQ_IOSCHED
#ifdef CONFIG_CFQ_GROUP_IOSCHED
#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \
cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \

27
init/Kconfig
View File

@ -612,6 +612,33 @@ config RT_GROUP_SCHED
endif #CGROUP_SCHED
config BLK_CGROUP
tristate "Block IO controller"
depends on CGROUPS && BLOCK
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.
This option only enables generic Block IO controller infrastructure.
One needs to also enable actual IO controlling logic in CFQ for it
to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
See Documentation/cgroups/blkio-controller.txt for more information.
config DEBUG_BLK_CGROUP
bool "Enable Block IO controller debugging"
depends on BLK_CGROUP
default n
---help---
Enable some debugging help. Currently it exports additional stat
files in a cgroup which can be useful for debugging.
endif # CGROUPS
config MM_OWNER