From: Paolo Valente <paolo.valente@linaro.org>
To: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block <linux-block@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Arie van der Hoeven <arie.vanderhoeven@seagate.com>,
Rory Chen <rory.c.chen@seagate.com>,
Gabriele Felici <felicigb@gmail.com>,
Gianmarco Lusvardi <glusvardi@posteo.net>,
Giulio Barabino <giuliobarabino99@gmail.com>,
Emiliano Maccaferri <inbox@emilianomaccaferri.com>
Subject: Re: [PATCH V6 4/8] block, bfq: turn bfqq_data into an array in bfq_io_cq
Date: Tue, 6 Dec 2022 09:00:22 +0100 [thread overview]
Message-ID: <9548A61A-7DEA-4FB2-85AE-0B75417B4B9E@linaro.org> (raw)
In-Reply-To: <3ec70cff-f1bc-1a45-a4db-10bb1d0e6266@opensource.wdc.com>
> Il giorno 21 nov 2022, alle ore 01:39, Damien Le Moal <damien.lemoal@opensource.wdc.com> ha scritto:
...
>>
>> bfqq = bfq_split_bfqq(bic, bfqq);
>> split = true;
>> diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
>> index f2e8ab91951c..e27897d66a0f 100644
>> --- a/block/bfq-iosched.h
>> +++ b/block/bfq-iosched.h
>> @@ -416,7 +416,7 @@ struct bfq_queue {
>> struct bfq_iocq_bfqq_data {
>> /*
>> * Snapshot of the has_short_time flag before merging; taken
>> - * to remember its value while the queue is merged, so as to
>> + * to remember its values while the queue is merged, so as to
>> * be able to restore it in case of split.
>> */
>> bool saved_has_short_ttime;
>> @@ -430,7 +430,7 @@ struct bfq_iocq_bfqq_data {
>> u64 saved_tot_idle_time;
>>
>> /*
>> - * Same purpose as the previous fields for the value of the
>> + * Same purpose as the previous fields for the values of the
>> * field keeping the queue's belonging to a large burst
>> */
>> bool saved_in_large_burst;
>> @@ -493,8 +493,12 @@ struct bfq_io_cq {
>> uint64_t blkcg_serial_nr; /* the current blkcg serial */
>> #endif
>>
>> - /* persistent data for associated synchronous process queue */
>> - struct bfq_iocq_bfqq_data bfqq_data;
>> + /*
>> + * Persistent data for associated synchronous process queues
>> + * (one queue per actuator, see field bfqq above). In
>> + * particular, each of these queues may undergo a merge.
>> + */
>> + struct bfq_iocq_bfqq_data bfqq_data[BFQ_MAX_ACTUATORS];
>
> I wonder if packing this together with struct bfq_queue would be cleaner.
> That would avoid the 2 arrays you have in this struct. Something like this:
>
> struct bfq_queue_data {
> struct bfq_queue *bfqq[2];
> struct bfq_iocq_bfqq_data iocq_data;
> }
>
> struct bfq_io_cq {
> ...
> struct bfq_queue_data bfqqd[BFQ_MAX_ACTUATORS];
> ...
> }
>
> Thinking aloud here. That may actually make the code more complicated.
I see your point, but, yes, this change would entail one more
indirection when accessing queues from io contexts.
Apart from this, I have applied all of your other suggestions here.
Thanks,
Paolo
>
>>
>> unsigned int requests; /* Number of requests this process has in flight */
>> };
>
> --
> Damien Le Moal
> Western Digital Research
next prev parent reply other threads:[~2022-12-06 8:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-03 16:26 [PATCH V6 0/8] block, bfq: extend bfq to support multi-actuator drives Paolo Valente
2022-11-03 16:26 ` [PATCH V6 1/8] block, bfq: split sync bfq_queues on a per-actuator basis Paolo Valente
2022-11-21 0:18 ` Damien Le Moal
2022-11-26 16:28 ` Paolo Valente
2022-11-28 14:32 ` Jens Axboe
2022-12-06 8:04 ` Paolo Valente
2022-11-03 16:26 ` [PATCH V6 2/8] block, bfq: forbid stable merging of queues associated with different actuators Paolo Valente
2022-11-21 0:20 ` Damien Le Moal
2022-11-03 16:26 ` [PATCH V6 3/8] block, bfq: move io_cq-persistent bfqq data into a dedicated struct Paolo Valente
2022-11-21 0:24 ` Damien Le Moal
2022-11-03 16:26 ` [PATCH V6 4/8] block, bfq: turn bfqq_data into an array in bfq_io_cq Paolo Valente
2022-11-21 0:39 ` Damien Le Moal
2022-12-06 8:00 ` Paolo Valente [this message]
2022-11-03 16:26 ` [PATCH V6 5/8] block, bfq: split also async bfq_queues on a per-actuator basis Paolo Valente
2022-11-21 0:52 ` Damien Le Moal
2022-11-03 16:26 ` [PATCH V6 6/8] block, bfq: retrieve independent access ranges from request queue Paolo Valente
2022-11-21 1:01 ` Damien Le Moal
2022-12-06 8:06 ` Paolo Valente
2022-12-06 8:29 ` Damien Le Moal
2022-12-06 8:41 ` Paolo Valente
2022-12-06 9:02 ` Damien Le Moal
2022-12-06 15:43 ` Paolo Valente
2022-12-06 23:34 ` Damien Le Moal
2022-12-08 10:43 ` Paolo Valente
2022-11-03 16:26 ` [PATCH V6 7/8] block, bfq: inject I/O to underutilized actuators Paolo Valente
2022-11-21 1:17 ` Damien Le Moal
2022-11-03 16:26 ` [PATCH V6 8/8] block, bfq: balance I/O injection among " Paolo Valente
2022-11-10 15:25 ` Arie van der Hoeven
2022-11-20 7:29 ` Paolo Valente
2022-11-20 22:06 ` Jens Axboe
2022-11-20 23:41 ` Damien Le Moal
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