From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>, linux-block@vger.kernel.org
Subject: Re: [PATCH 3/3] block: only allocate poll_stats if there's a user of them
Date: Tue, 23 Nov 2021 10:59:53 -0800 [thread overview]
Message-ID: <YZ06Kd6qpRPt3KG4@infradead.org> (raw)
In-Reply-To: <b24a297d-3d57-7f8d-1932-da614454b28d@kernel.dk>
On Tue, Nov 23, 2021 at 11:58:42AM -0700, Jens Axboe wrote:
> On 11/23/21 11:50 AM, Christoph Hellwig wrote:
> >> + spin_lock_irq(&q->stats->lock);
> >> + if (q->poll_stat) {
> >> + spin_unlock_irq(&q->stats->lock);
> >> + kfree(poll_stat);
> >> + return true;
> >> + }
> >> + q->poll_stat = poll_stat;
> >> + spin_unlock_irq(&q->stats->lock);
> >
> > If we'd use a cmpxchg to install the pointer we could keep the
> > blk_queue_stats definition private.
>
> How about we just move this alloc+enable logic into blk-stat.c instead?
That's a good idea either way. But I think cmpxchg is much better
for installing a pointer than an unrelated lock.
next prev parent reply other threads:[~2021-11-23 18:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 17:10 [PATCHSET 0/3 v2] Misc block cleanups Jens Axboe
2021-11-23 17:10 ` [PATCH 1/3] block: move io_context creation into where it's needed Jens Axboe
2021-11-23 18:46 ` Christoph Hellwig
2021-11-23 18:58 ` Jens Axboe
2021-11-23 17:10 ` [PATCH 2/3] blk-ioprio: don't set bio priority if not needed Jens Axboe
2021-11-23 18:51 ` Christoph Hellwig
2021-11-23 17:10 ` [PATCH 3/3] block: only allocate poll_stats if there's a user of them Jens Axboe
2021-11-23 18:50 ` Christoph Hellwig
2021-11-23 18:58 ` Jens Axboe
2021-11-23 18:59 ` Christoph Hellwig [this message]
2021-11-23 19:03 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2021-11-23 16:18 [PATCHSET 0/3] Misc block cleanups Jens Axboe
2021-11-23 16:18 ` [PATCH 3/3] block: only allocate poll_stats if there's a user of them Jens Axboe
2021-11-23 16:21 ` Johannes Thumshirn
2021-11-23 16:27 ` Jens Axboe
2021-11-23 16:41 ` Christoph Hellwig
2021-11-23 16:44 ` Jens Axboe
2021-11-23 17:05 ` Christoph Hellwig
2021-11-23 17:06 ` Jens Axboe
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=YZ06Kd6qpRPt3KG4@infradead.org \
--to=hch@infradead.org \
--cc=axboe@kernel.dk \
--cc=linux-block@vger.kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox