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author | Corrado Zoccolo <czoccolo@gmail.com> | 2010-09-20 15:24:50 +0200 |
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committer | Jens Axboe <jaxboe@fusionio.com> | 2010-09-20 15:24:50 +0200 |
commit | 749ef9f8423054e326f3a246327ed2db4b6d395f (patch) | |
tree | 388df763e4e731f5d9b4d8dcaedca641521571e3 | |
parent | 6d0aed7a38d06284db2a0e46c0a072b0c1c3299b (diff) | |
download | kernel_samsung_smdk4412-749ef9f8423054e326f3a246327ed2db4b6d395f.tar.gz kernel_samsung_smdk4412-749ef9f8423054e326f3a246327ed2db4b6d395f.tar.bz2 kernel_samsung_smdk4412-749ef9f8423054e326f3a246327ed2db4b6d395f.zip |
cfq: improve fsync performance for small files
Fsync performance for small files achieved by cfq on high-end disks is
lower than what deadline can achieve, due to idling introduced between
the sync write happening in process context and the journal commit.
Moreover, when competing with a sequential reader, a process writing
small files and fsync-ing them is starved.
This patch fixes the two problems by:
- marking journal commits as WRITE_SYNC, so that they get the REQ_NOIDLE
flag set,
- force all queues that have REQ_NOIDLE requests to be put in the noidle
tree.
Having the queue associated to the fsync-ing process and the one associated
to journal commits in the noidle tree allows:
- switching between them without idling,
- fairness vs. competing idling queues, since they will be serviced only
after the noidle tree expires its slice.
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Tested-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r-- | block/cfq-iosched.c | 18 | ||||
-rw-r--r-- | fs/jbd/commit.c | 2 | ||||
-rw-r--r-- | fs/jbd2/commit.c | 2 |
3 files changed, 6 insertions, 16 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index b9f86190763..68459262173 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -216,7 +216,6 @@ struct cfq_data { enum wl_type_t serving_type; unsigned long workload_expires; struct cfq_group *serving_group; - bool noidle_tree_requires_idle; /* * Each priority tree is sorted by next_request position. These @@ -2126,7 +2125,6 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) slice = max_t(unsigned, slice, CFQ_MIN_TT); cfq_log(cfqd, "workload slice:%d", slice); cfqd->workload_expires = jiffies + slice; - cfqd->noidle_tree_requires_idle = false; } static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) @@ -3108,7 +3106,9 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfqq->queued[0] + cfqq->queued[1] >= 4) cfq_mark_cfqq_deep(cfqq); - if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || + if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) + enable_idle = 0; + else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) enable_idle = 0; else if (sample_valid(cic->ttime_samples)) { @@ -3421,17 +3421,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfq_slice_expired(cfqd, 1); else if (sync && cfqq_empty && !cfq_close_cooperator(cfqd, cfqq)) { - cfqd->noidle_tree_requires_idle |= - !(rq->cmd_flags & REQ_NOIDLE); - /* - * Idling is enabled for SYNC_WORKLOAD. - * SYNC_NOIDLE_WORKLOAD idles at the end of the tree - * only if we processed at least one !REQ_NOIDLE request - */ - if (cfqd->serving_type == SYNC_WORKLOAD - || cfqd->noidle_tree_requires_idle - || cfqq->cfqg->nr_cfqq == 1) - cfq_arm_slice_timer(cfqd); + cfq_arm_slice_timer(cfqd); } } diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c index 95d8c11c929..3f030e9efea 100644 --- a/fs/jbd/commit.c +++ b/fs/jbd/commit.c @@ -318,7 +318,7 @@ void journal_commit_transaction(journal_t *journal) int first_tag = 0; int tag_flag; int i; - int write_op = WRITE; + int write_op = WRITE_SYNC; /* * First job: lock down the current transaction and wait for diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 7c068c189d8..80910f51d4b 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -360,7 +360,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) int tag_bytes = journal_tag_bytes(journal); struct buffer_head *cbh = NULL; /* For transactional checksums */ __u32 crc32_sum = ~0; - int write_op = WRITE; + int write_op = WRITE_SYNC; /* * First job: lock down the current transaction and wait for |