public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: lizefan.x@bytedance.com, hannes@cmpxchg.org, corbet@lwn.net,
	kamalesh.babulal@oracle.com, haitao.huang@linux.intel.com,
	cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 -next] cgroup/misc: Introduce misc.peak
Date: Tue, 2 Jul 2024 06:44:41 -1000	[thread overview]
Message-ID: <ZoQueSY_8NYcApfi@slm.duckdns.org> (raw)
In-Reply-To: <20240702075718.2657635-1-xiujianfeng@huawei.com>

Hello,

On Tue, Jul 02, 2024 at 07:57:18AM +0000, Xiu Jianfeng wrote:
>  struct misc_res {
>  	u64 max;
> +	u64 watermark;

atomic64_t is probably better here.

>  	atomic64_t usage;
>  	atomic64_t events;
>  };
...
> +static void misc_cg_update_watermark(struct misc_res *res, u64 new_usage)
> +{
> +	u64 old;
> +

How about just while (true)?

> +	do {
> +		old = READ_ONCE(res->watermark);

here, you can use atomic64_read().

> +		if (new_usage <= old)
> +			break;
> +		if (cmpxchg(&res->watermark, old, new_usage) == old)

and atomic64_cmpxchg().

> +			break;
> +	} while (1);
> +}

Thanks.

-- 
tejun

      parent reply	other threads:[~2024-07-02 16:44 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-02  7:57 [PATCH v4 -next] cgroup/misc: Introduce misc.peak Xiu Jianfeng
2024-07-02  8:41 ` Kamalesh Babulal
2024-07-02 16:44 ` Tejun Heo [this message]

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=ZoQueSY_8NYcApfi@slm.duckdns.org \
    --to=tj@kernel.org \
    --cc=cgroups@vger.kernel.org \
    --cc=corbet@lwn.net \
    --cc=haitao.huang@linux.intel.com \
    --cc=hannes@cmpxchg.org \
    --cc=kamalesh.babulal@oracle.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lizefan.x@bytedance.com \
    --cc=xiujianfeng@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox