diff options
author | Vivek Goyal <vgoyal@redhat.com> | 2009-12-03 12:59:50 -0500 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2009-12-03 19:28:52 +0100 |
commit | 8682e1f15f26dae9a9e8af794d179055fbd81166 (patch) | |
tree | d6e87631f91527656490df9b28be107fb5e974b0 /block/cfq-iosched.c | |
parent | 220841906fccafaf4094e87bdb6d252e20cf8c7c (diff) | |
download | linux-stable-8682e1f15f26dae9a9e8af794d179055fbd81166.tar.gz linux-stable-8682e1f15f26dae9a9e8af794d179055fbd81166.tar.bz2 linux-stable-8682e1f15f26dae9a9e8af794d179055fbd81166.zip |
blkio: Provide some isolation between groups
o Do not allow following three operations across groups for isolation.
- selection of co-operating queues
- preemtpions across groups
- request merging across groups.
o Async queues are currently global and not per group. Allow preemption of
an async queue if a sync queue in other group gets backlogged.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r-- | block/cfq-iosched.c | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 7d345e772d88..3a62ce95daec 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1461,6 +1461,9 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq, struct cfq_io_context *cic; struct cfq_queue *cfqq; + /* Deny merge if bio and rq don't belong to same cfq group */ + if ((RQ_CFQQ(rq))->cfqg != cfq_get_cfqg(cfqd, 0)) + return false; /* * Disallow merge of a sync bio into an async request. */ @@ -1698,6 +1701,10 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, if (!cfqq) return NULL; + /* If new queue belongs to different cfq_group, don't choose it */ + if (cur_cfqq->cfqg != cfqq->cfqg) + return NULL; + /* * It only makes sense to merge sync queues. */ @@ -2950,22 +2957,12 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (!cfqq) return false; - if (cfq_slice_used(cfqq)) - return true; - if (cfq_class_idle(new_cfqq)) return false; if (cfq_class_idle(cfqq)) return true; - /* Allow preemption only if we are idling on sync-noidle tree */ - if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && - cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && - new_cfqq->service_tree->count == 2 && - RB_EMPTY_ROOT(&cfqq->sort_list)) - return true; - /* * if the new request is sync, but the currently running queue is * not, let the sync request have priority. @@ -2973,6 +2970,19 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) return true; + if (new_cfqq->cfqg != cfqq->cfqg) + return false; + + if (cfq_slice_used(cfqq)) + return true; + + /* Allow preemption only if we are idling on sync-noidle tree */ + if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && + cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && + new_cfqq->service_tree->count == 2 && + RB_EMPTY_ROOT(&cfqq->sort_list)) + return true; + /* * So both queues are sync. Let the new request get disk time if * it's a metadata request and the current queue is doing regular IO. |