From: Jens Axboe <axboe@kernel.dk>
To: Mike Snitzer <snitzer@redhat.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com,
Mikulas Patocka <mpatocka@redhat.com>
Subject: Re: [PATCH v2 4/6] block: switch to per-cpu in-flight counters
Date: Wed, 5 Dec 2018 10:30:38 -0700 [thread overview]
Message-ID: <d6a741cd-ea75-19d0-13e3-eb1321e617b4@kernel.dk> (raw)
In-Reply-To: <20181130222226.77216-5-snitzer@redhat.com>
On 11/30/18 3:22 PM, Mike Snitzer wrote:
> diff --git a/block/genhd.c b/block/genhd.c
> index cdf174d7d329..d4c9dd65def6 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -45,53 +45,76 @@ static void disk_add_events(struct gendisk *disk);
> static void disk_del_events(struct gendisk *disk);
> static void disk_release_events(struct gendisk *disk);
>
> -void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
> +void part_inc_in_flight(struct request_queue *q, int cpu, struct hd_struct *part, int rw)
> {
> if (queue_is_mq(q))
> return;
>
> - atomic_inc(&part->in_flight[rw]);
> + local_inc(&per_cpu_ptr(part->dkstats, cpu)->in_flight[rw]);
I mentioned this in a previous email, but why isn't this just using
this_cpu_inc? There's also no need to pass in the cpu, if we're not
running with preempt disabled already we have a problem.
--
Jens Axboe
next prev parent reply other threads:[~2018-12-05 17:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 0:42 [PATCH 0/3] per-cpu in_flight counters for bio-based drivers Mikulas Patocka
2018-11-30 14:43 ` Mike Snitzer
2018-11-30 15:50 ` Mike Snitzer
2018-11-30 19:57 ` Mike Snitzer
2018-11-30 22:22 ` [PATCH v2 0/6] " Mike Snitzer
2018-11-30 22:22 ` [PATCH v2 1/6] dm: dont rewrite dm_disk(md)->part0.in_flight Mike Snitzer
2018-11-30 22:22 ` [PATCH v2 2/6] dm rq: leverage blk_mq_queue_busy() to check for outstanding IO Mike Snitzer
2018-11-30 22:22 ` [PATCH v2 3/6] block: delete part_round_stats and switch to less precise counting Mike Snitzer
2018-11-30 22:22 ` [PATCH v2 4/6] block: switch to per-cpu in-flight counters Mike Snitzer
2018-12-05 17:30 ` Jens Axboe [this message]
2018-12-05 17:49 ` Mike Snitzer
2018-12-05 17:54 ` Jens Axboe
2018-12-05 18:03 ` Mike Snitzer
2018-12-05 18:04 ` Jens Axboe
2018-12-05 18:18 ` Mike Snitzer
2018-12-05 18:35 ` Jens Axboe
2018-11-30 22:22 ` [PATCH v2 5/6] block: return just one value from part_in_flight Mike Snitzer
2018-11-30 22:22 ` [PATCH v2 6/6] dm: remove the pending IO accounting Mike Snitzer
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