From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Yu Kuai <yukuai3@huawei.com>
Subject: Re: [PATCH 6/6] blk-mq: manage hctx map via xarray
Date: Wed, 2 Mar 2022 17:53:44 +0800 [thread overview]
Message-ID: <Yh8+qA4p6EWGFbtG@T590> (raw)
In-Reply-To: <Yh8pwiR5DWC9ELDD@infradead.org>
On Wed, Mar 02, 2022 at 12:24:34AM -0800, Christoph Hellwig wrote:
> On Wed, Mar 02, 2022 at 10:06:04AM +0800, Ming Lei wrote:
> > I did considered xa_for_each(), but it requires rcu read lock.
>
> No, I doesn't. It just takes a RCU lock internally.
OK.
>
> > Also queue_for_each_hw_ctx() is supposed to not run in fast path,
> > meantime xa_load() is lightweight enough too, so repeated xa_load()
> > is fine here.
>
> I'd rather have the clarity of the proper iterators.
Another point is that 'unsigned long *' is passed to xa_find() as index.
However, almost all users of queue_for_each_hw_ctx() defines hctx index
as 'unsigned int'.
If we switch to xa_for_each(), the type of hctx index needs to be changed
to 'unsigned long' for every queue_for_each_hw_ctx(). But xa_load()
needn't such change.
Also from user viewpoint, looks 'unsigned long' change for hctx index is
still a bit confusing, IMO.
Thanks,
Ming
next prev parent reply other threads:[~2022-03-02 9:54 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-28 9:04 [PATCH 0/6] blk-mq: update_nr_hw_queues related improvement & bugfix Ming Lei
2022-02-28 9:04 ` [PATCH 1/6] blk-mq: figure out correct numa node for hw queue Ming Lei
2022-03-01 13:30 ` Christoph Hellwig
2022-03-01 19:19 ` John Garry
2022-03-02 1:47 ` Ming Lei
2022-03-02 9:02 ` John Garry
2022-03-02 9:22 ` Ming Lei
2022-03-02 10:11 ` John Garry
2022-02-28 9:04 ` [PATCH 2/6] blk-mq: simplify reallocation of hw ctxs a bit Ming Lei
2022-03-01 13:30 ` Christoph Hellwig
2022-02-28 9:04 ` [PATCH 3/6] blk-mq: re-config poll after queue map is changed Ming Lei
2022-03-01 13:31 ` Christoph Hellwig
2022-02-28 9:04 ` [PATCH 4/6] block: mtip32xx: don't touch q->queue_hw_ctx Ming Lei
2022-03-01 13:32 ` Christoph Hellwig
2022-02-28 9:04 ` [PATCH 5/6] blk-mq: add helper of blk_mq_get_hctx to retrieve hctx via its index Ming Lei
2022-03-01 13:33 ` Christoph Hellwig
2022-02-28 9:04 ` [PATCH 6/6] blk-mq: manage hctx map via xarray Ming Lei
2022-02-28 17:36 ` kernel test robot
2022-02-28 17:57 ` kernel test robot
2022-03-01 9:08 ` Ming Lei
2022-03-01 9:08 ` Ming Lei
2022-03-01 13:37 ` Christoph Hellwig
2022-03-02 2:06 ` Ming Lei
2022-03-02 8:24 ` Christoph Hellwig
2022-03-02 9:53 ` Ming Lei [this message]
2022-03-02 9:59 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Yh8+qA4p6EWGFbtG@T590 \
--to=ming.lei@redhat.com \
--cc=axboe@kernel.dk \
--cc=hch@infradead.org \
--cc=linux-block@vger.kernel.org \
--cc=yukuai3@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.