netdev - Re: [PATCH 2/9] dma: Convert from tasklet to BH workqueue

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: <ZgbuotY4IX4iHm9U@matsya>
Date: Fri, 29 Mar 2024 22:08:58 +0530
From: Vinod Koul <vkoul@...nel.org>
To: Allen <allen.lkml@...il.com>
Cc: Arnd Bergmann <arnd@...db.de>, Allen Pais <apais@...ux.microsoft.com>,
	linux-kernel@...r.kernel.org, Tejun Heo <tj@...nel.org>,
	Kees Cook <keescook@...omium.org>, Hector Martin <marcan@...can.st>,
	Sven Peter <sven@...npeter.dev>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Ray Jui <rjui@...adcom.com>, Scott Branden <sbranden@...adcom.com>,
	Paul Cercueil <paul@...pouillou.net>, Eugeniy.Paltsev@...opsys.com,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Viresh Kumar <vireshk@...nel.org>, Frank Li <Frank.Li@....com>,
	Leo Li <leoyang.li@....com>, zw@...kernel.org,
	Zhou Wang <wangzhou1@...ilicon.com>, haijie1@...wei.com,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Sean Wang <sean.wang@...iatek.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Andreas Färber <afaerber@...e.de>,
	logang@...tatee.com, Daniel Mack <daniel@...que.org>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Orson Zhai <orsonzhai@...il.com>,
	Baolin Wang <baolin.wang@...ux.alibaba.com>,
	Chunyan Zhang <zhang.lyra@...il.com>,
	Patrice Chotard <patrice.chotard@...s.st.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Chen-Yu Tsai <wens@...e.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>, peter.ujfalusi@...il.com,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
	Jassi Brar <jassisinghbrar@...il.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	maintainers@...echerrydvr.com, aubin.constans@...rochip.com,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Manuel Lauss <manuel.lauss@...il.com>,
	Michał Mirosław <mirq-linux@...e.qmqm.pl>,
	"jh80.chung" <jh80.chung@...sung.com>, oakad@...oo.com,
	Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
	Masami Hiramatsu <mhiramat@...nel.org>, brucechang@....com.tw,
	HaraldWelte@...tech.com, pierre@...man.eu,
	Duncan Sands <duncan.sands@...e.fr>,
	Alan Stern <stern@...land.harvard.edu>,
	Oliver Neukum <oneukum@...e.com>,
	openipmi-developer@...ts.sourceforge.net, dmaengine@...r.kernel.org,
	asahi@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
	linux-rpi-kernel@...ts.infradead.org, linux-mips@...r.kernel.org,
	imx@...ts.linux.dev, linuxppc-dev@...ts.ozlabs.org,
	linux-mediatek@...ts.infradead.org,
	linux-actions@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
	linux-riscv@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
	linux-tegra@...r.kernel.org, linux-hyperv@...r.kernel.org,
	linux-rdma@...r.kernel.org, linux-media@...r.kernel.org,
	"linux-mmc @ vger . kernel . org" <linux-mmc@...r.kernel.org>,
	Linux-OMAP <linux-omap@...r.kernel.org>,
	Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
	linux-s390@...r.kernel.org, Netdev <netdev@...r.kernel.org>,
	linux-usb@...r.kernel.org
Subject: Re: [PATCH 2/9] dma: Convert from tasklet to BH workqueue

On 28-03-24, 13:01, Allen wrote:
> > >> > Since almost every driver associates the tasklet with the
> > >> > dma_chan, we could go one step further and add the
> > >> > work_queue structure directly into struct dma_chan,
> > >> > with the wrapper operating on the dma_chan rather than
> > >> > the work_queue.
> > >>
> > >> I think that is very great idea. having this wrapped in dma_chan would
> > >> be very good way as well
> > >>
> > >> Am not sure if Allen is up for it :-)
> > >
> > >  Thanks Arnd, I know we did speak about this at LPC. I did start
> > > working on using completion. I dropped it as I thought it would
> > > be easier to move to workqueues.
> >
> > It's definitely easier to do the workqueue conversion as a first
> > step, and I agree adding support for the completion right away is
> > probably too much. Moving the work_struct into the dma_chan
> > is probably not too hard though, if you leave your current
> > approach for the cases where the tasklet is part of the
> > dma_dev rather than the dma_chan.
> >
> 
>  Alright, I will work on moving work_struck into the dma_chan and
> leave the dma_dev as is (using bh workqueues) and post a RFC.
> Once reviewed, I could move to the next step.

That might be better from a performance pov but the current design is a
global tasklet and not a per chan one... We would need to carefully
review and test this for sure

-- 
~Vinod