From: Christoph Hellwig <hch@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
darklight2357@icloud.com, Josef Bacik <josef@toxicpanda.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
cgroups@vger.kernel.org
Subject: Re: [PATCH 2/2 block/for-6.2] blk-iolatency: Make initialization lazy
Date: Mon, 12 Dec 2022 00:53:26 -0800 [thread overview]
Message-ID: <Y5bsBuwjcbHEjhIw@infradead.org> (raw)
In-Reply-To: <Y5TRU2+s379DhUbj@slm.duckdns.org>
> +static int blk_iolatency_try_init(char *input)
> +{
> + static DEFINE_MUTEX(init_mutex);
> + struct block_device *bdev;
> + int ret = 0;
> +
> + bdev = blkcg_conf_open_bdev(&input);
> + if (IS_ERR(bdev))
> + return PTR_ERR(bdev);
> +retry:
> ret = blkg_conf_prep(blkcg, &blkcg_policy_iolatency, buf, &ctx);
> + if (ret == -EOPNOTSUPP) {
> + ret = blk_iolatency_try_init(buf);
It's a little sad to do two block device lookups here (even if it
obviously doesn't matter for performance). I wonder if it would
make sense to explicitly support the lazy init pattern
in blkg_conf_prep somehow.
Otherwise I'm all for the lazy init.
next prev parent reply other threads:[~2022-12-12 8:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-10 18:33 [PATCH 1/2 block/for-6.2] blk-iolatency: Fix memory leak on add_disk() failures Tejun Heo
2022-12-10 18:34 ` [PATCH 2/2 block/for-6.2] blk-iolatency: Make initialization lazy Tejun Heo
2022-12-12 8:53 ` Christoph Hellwig [this message]
2022-12-12 22:44 ` Tejun Heo
2022-12-10 18:54 ` [PATCH 1/2 block/for-6.2] blk-iolatency: Fix memory leak on add_disk() failures Linus Torvalds
2022-12-12 8:47 ` Christoph Hellwig
2022-12-14 19:43 ` (subset) " Jens Axboe
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