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Message-ID: <4A0D1C55.9040700@cn.fujitsu.com>
Date: Fri, 15 May 2009 15:40:05 +0800
From: Gui Jianfeng <guijianfeng@...fujitsu.com>
To: Vivek Goyal <vgoyal@...hat.com>
CC: Nauman Rafique <nauman@...gle.com>, dpshah@...gle.com,
lizf@...fujitsu.com, mikew@...gle.com, fchecconi@...il.com,
paolo.valente@...more.it, jens.axboe@...cle.com,
ryov@...inux.co.jp, fernando@....ntt.co.jp, s-uchida@...jp.nec.com,
taka@...inux.co.jp, jmoyer@...hat.com, dhaval@...ux.vnet.ibm.com,
balbir@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
containers@...ts.linux-foundation.org, righi.andrea@...il.com,
agk@...hat.com, dm-devel@...hat.com, snitzer@...hat.com,
m-ikeda@...jp.nec.com, akpm@...ux-foundation.org
Subject: Re: [PATCH] io-controller: Add io group reference handling for request
Vivek Goyal wrote:
...
> Ok, here is the patch which gets rid of rq->iog and rq->rl fields. Good to
> see some code and data structures trimming. It seems to be working fine for me.
>
>
> o Get rid of rq->iog field and rq->rl fields. request descriptor stores
> the pointer the the queue it belongs to (rq->ioq) and from the io queue one
> can determine the group queue belongs to hence request belongs to. Thanks
> to Nauman for the idea.
>
> o There are couple of places where rq->ioq information is not present yet
> as request and queue are being setup. In those places "bio" is passed
> around as function argument to determine the group rq will go into. I
> did not pass "iog" as function argument becuase when memory is scarce,
> we can release queue lock and sleep to wait for memory to become available
> and once we wake up, it is possible that io group is gone. Passing bio
> around helps that one shall have to remap bio to right group after waking
> up.
>
> o Got rid of io_lookup_io_group_current() function and merged it with
> io_get_io_group() to also take care of looking for group using current
> task info and not from bio.
Hi Vivek,
This patch gets rid of "curr" from io_get_io_group, and seems to be
working fine for me.
Signed-off-by: Gui Jianfeng <guijianfeng@...fujitsu.com>
---
block/cfq-iosched.c | 12 ++++++------
block/elevator-fq.c | 16 ++++++++--------
block/elevator-fq.h | 2 +-
3 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index c0bb8db..bf87843 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -196,7 +196,7 @@ static struct cfq_queue *cic_bio_to_cfqq(struct cfq_data *cfqd,
* async bio tracking is enabled and we are not caching
* async queue pointer in cic.
*/
- iog = io_get_io_group(cfqd->queue, bio, 0, 0);
+ iog = io_get_io_group(cfqd->queue, bio, 0);
if (!iog) {
/*
* May be this is first rq/bio and io group has not
@@ -1294,7 +1294,7 @@ static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
spin_lock_irqsave(q->queue_lock, flags);
- iog = io_get_io_group(q, NULL, 0, 1);
+ iog = io_get_io_group(q, NULL, 0);
if (async_cfqq != NULL) {
__iog = cfqq_to_io_group(async_cfqq);
@@ -1346,9 +1346,9 @@ retry:
* back.
*/
if (bio)
- iog = io_get_io_group(q, bio, 1, 0);
+ iog = io_get_io_group(q, bio, 1);
else
- iog = io_get_io_group(q, NULL, 1, 1);
+ iog = io_get_io_group(q, NULL, 1);
cic = cfq_cic_lookup(cfqd, ioc);
/* cic always exists here */
@@ -1469,9 +1469,9 @@ cfq_get_queue(struct cfq_data *cfqd, struct bio *bio, int is_sync,
struct io_group *iog = NULL;
if (bio)
- iog = io_get_io_group(cfqd->queue, bio, 1, 0);
+ iog = io_get_io_group(cfqd->queue, bio, 1);
else
- iog = io_get_io_group(cfqd->queue, NULL, 1, 1);
+ iog = io_get_io_group(cfqd->queue, NULL, 1);
if (!is_sync) {
async_cfqq = io_group_async_queue_prio(iog, ioprio_class,
diff --git a/block/elevator-fq.c b/block/elevator-fq.c
index 9b7319e..951c163 100644
--- a/block/elevator-fq.c
+++ b/block/elevator-fq.c
@@ -1006,7 +1006,7 @@ struct request_list *io_group_get_request_list(struct request_queue *q,
{
struct io_group *iog;
- iog = io_get_io_group(q, bio, 1, 0);
+ iog = io_get_io_group(q, bio, 1);
BUG_ON(!iog);
return &iog->rl;
}
@@ -1470,7 +1470,7 @@ struct io_cgroup *get_iocg_from_bio(struct bio *bio)
*
*/
struct io_group *io_get_io_group(struct request_queue *q, struct bio *bio,
- int create, int curr)
+ int create)
{
struct cgroup *cgroup;
struct io_group *iog;
@@ -1478,7 +1478,7 @@ struct io_group *io_get_io_group(struct request_queue *q, struct bio *bio,
rcu_read_lock();
- if (curr)
+ if (!bio)
cgroup = task_cgroup(current, io_subsys_id);
else
cgroup = get_cgroup_from_bio(bio);
@@ -1959,7 +1959,7 @@ int io_group_allow_merge(struct request *rq, struct bio *bio)
return 1;
/* Determine the io group of the bio submitting task */
- iog = io_get_io_group(q, bio, 0, 0);
+ iog = io_get_io_group(q, bio, 0);
if (!iog) {
/* May be task belongs to a differet cgroup for which io
* group has not been setup yet. */
@@ -2000,9 +2000,9 @@ int elv_fq_set_request_ioq(struct request_queue *q, struct request *rq,
retry:
/* Determine the io group request belongs to */
if (bio)
- iog = io_get_io_group(q, bio, 1, 0);
+ iog = io_get_io_group(q, bio, 1);
else
- iog = io_get_io_group(q, bio, 1, 1);
+ iog = io_get_io_group(q, NULL, 1);
BUG_ON(!iog);
@@ -2098,7 +2098,7 @@ struct io_queue *elv_lookup_ioq_bio(struct request_queue *q, struct bio *bio)
struct io_group *iog;
/* lookup the io group and io queue of the bio submitting task */
- iog = io_get_io_group(q, bio, 0, 0);
+ iog = io_get_io_group(q, bio, 0);
if (!iog) {
/* May be bio belongs to a cgroup for which io group has
* not been setup yet. */
@@ -2159,7 +2159,7 @@ struct io_group *io_lookup_io_group_current(struct request_queue *q)
EXPORT_SYMBOL(io_lookup_io_group_current);
struct io_group *io_get_io_group(struct request_queue *q, struct bio *bio,
- int create, int curr)
+ int create)
{
return q->elevator->efqd.root_group;
}
diff --git a/block/elevator-fq.h b/block/elevator-fq.h
index 8d190ab..d8d8f61 100644
--- a/block/elevator-fq.h
+++ b/block/elevator-fq.h
@@ -657,7 +657,7 @@ extern void io_group_set_async_queue(struct io_group *iog, int ioprio_class,
int ioprio, struct io_queue *ioq);
extern struct io_group *io_lookup_io_group_current(struct request_queue *q);
extern struct io_group *io_get_io_group(struct request_queue *q,
- struct bio *bio, int create, int curr);
+ struct bio *bio, int create);
extern int elv_nr_busy_ioq(struct elevator_queue *e);
extern int elv_nr_busy_rt_ioq(struct elevator_queue *e);
extern struct io_queue *elv_alloc_ioq(struct request_queue *q, gfp_t gfp_mask);
--
1.5.4.rc3
--
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