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| author | Paolo Valente <paolo.valente@linaro.org> | 2019-06-25 07:12:45 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-06-25 09:07:34 -0600 |
| commit | 24792ad01cb659c8b5899de2af6e8ca250f93df3 (patch) | |
| tree | ccb4a16c5352a4334c88e2ec647e49c66947857f /block | |
| parent | db599f9ed9bd31b018b6c48ad7c6b21d5b790ecf (diff) | |
| download | linux-24792ad01cb659c8b5899de2af6e8ca250f93df3.tar.gz linux-24792ad01cb659c8b5899de2af6e8ca250f93df3.tar.bz2 linux-24792ad01cb659c8b5899de2af6e8ca250f93df3.zip | |
block, bfq: update base request service times when possible
I/O injection gets reduced if it increases the request service times
of the victim queue beyond a certain threshold. The threshold, in its
turn, is computed as a function of the base service time enjoyed by
the queue when it undergoes no injection.
As a consequence, for injection to work properly, the above base value
has to be accurate. In this respect, such a value may vary over
time. For example, it varies if the size or the spatial locality of
the I/O requests in the queue change. It is then important to update
this value whenever possible. This commit performs this update.
Reported-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Tested-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bfq-iosched.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 05041f84b8da..62442083b147 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5496,7 +5496,18 @@ static void bfq_update_inject_limit(struct bfq_data *bfqd, * start trying injection. */ bfqq->inject_limit = max_t(unsigned int, 1, old_limit); - } + } else if (!bfqd->rqs_injected && bfqd->rq_in_driver == 1) + /* + * No I/O injected and no request still in service in + * the drive: these are the exact conditions for + * computing the base value of the total service time + * for bfqq. So let's update this value, because it is + * rather variable. For example, it varies if the size + * or the spatial locality of the I/O requests in bfqq + * change. + */ + bfqq->last_serv_time_ns = tot_time_ns; + /* update complete, not waiting for any request completion any longer */ bfqd->waited_rq = NULL; |