netdev - Re: [PATCH net-next v2 4/4] net: hns3: support skb's frag page recycling based on page pool

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YTjWK1rNsYIcTt4O@apalos.home>
Date:   Wed, 8 Sep 2021 18:26:35 +0300
From:   Ilias Apalodimas <ilias.apalodimas@...aro.org>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     moyufeng <moyufeng@...wei.com>,
        Yunsheng Lin <linyunsheng@...wei.com>, davem@...emloft.net,
        alexander.duyck@...il.com, linux@...linux.org.uk, mw@...ihalf.com,
        linuxarm@...neuler.org, yisen.zhuang@...wei.com,
        salil.mehta@...wei.com, thomas.petazzoni@...tlin.com,
        hawk@...nel.org, ast@...nel.org, daniel@...earbox.net,
        john.fastabend@...il.com, akpm@...ux-foundation.org,
        peterz@...radead.org, will@...nel.org, willy@...radead.org,
        vbabka@...e.cz, fenghua.yu@...el.com, guro@...com,
        peterx@...hat.com, feng.tang@...el.com, jgg@...pe.ca,
        mcroce@...rosoft.com, hughd@...gle.com, jonathan.lemon@...il.com,
        alobakin@...me, willemb@...gle.com, wenxu@...oud.cn,
        cong.wang@...edance.com, haokexin@...il.com, nogikh@...gle.com,
        elver@...gle.com, yhs@...com, kpsingh@...nel.org,
        andrii@...nel.org, kafai@...com, songliubraving@...com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        bpf@...r.kernel.org, chenhao288@...ilicon.com
Subject: Re: [PATCH net-next v2 4/4] net: hns3: support skb's frag page
 recycling based on page pool

Hi Jakub,

On Wed, Sep 08, 2021 at 08:08:43AM -0700, Jakub Kicinski wrote:
> On Wed, 8 Sep 2021 16:31:40 +0800 moyufeng wrote:
> >     After adding page pool to hns3 receiving package process,
> > we want to add some debug info. Such as below:
> > 
> > 1. count of page pool allocate and free page, which is defined
> > for pages_state_hold_cnt and pages_state_release_cnt in page
> > pool framework.
> > 
> > 2. pool size、order、nid、dev、max_len, which is setted for
> > each rx ring in hns3 driver.
> > 
> > In this regard, we consider two ways to show these info：
> > 
> > 1. Add it to queue statistics and query it by ethtool -S.
> > 
> > 2. Add a file node "page_pool_info" for debugfs, then cat this
> > file node, print as below:
> > 
> > queue_id  allocate_cnt  free_cnt  pool_size  order  nid  dev  max_len
> > 000		   xxx       xxx        xxx    xxx  xxx  xxx      xxx
> > 001
> > 002
> > .
> > .
> > 	
> > Which one is more acceptable, or would you have some other suggestion?
> 
> Normally I'd say put the stats in ethtool -S and the rest in debugfs
> but I'm not sure if exposing pages_state_hold_cnt and
> pages_state_release_cnt directly. Those are short counters, and will
> very likely wrap. They are primarily meaningful for calculating
> page_pool_inflight(). Given this I think their semantics may be too
> confusing for an average ethtool -S user.
> 
> Putting all the information in debugfs seems like a better idea.

I can't really disagree on the aforementioned stats being confusing.
However at some point we'll want to add more useful page_pool stats (e.g the
percentage of the page/page fragments that are hitting the recycling path).
Would it still be 'ok' to have info split across ethtool and debugfs?

Regards
/Ilias