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From: Konstantin Ananyev <konstantin.ananyev@huawei.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Wathsala Vithanage <wathsala.vithanage@arm.com>,
	Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>,
	Tyler Retzlaff <roretzla@linux.microsoft.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	Ola Liljedahl <ola.liljedahl@arm.com>,
	"vattunuru@marvell.com" <vattunuru@marvell.com>
Subject: RE: [PATCH 1/1] eal: correct memory ordering in MCS lock
Date: Tue, 4 Nov 2025 08:18:50 +0000	[thread overview]
Message-ID: <9a7a720e91f546879368a0ed83dd7224@huawei.com> (raw)
In-Reply-To: <20251103104803.30464227@phoenix>



> On Mon, 3 Nov 2025 18:06:05 +0000
> Konstantin Ananyev <konstantin.ananyev@huawei.com> wrote:
> 
> > >
> > > On 11/3/25 11:07, Stephen Hemminger wrote:
> > > > On Mon, 3 Nov 2025 09:12:39 -0600
> > > > Wathsala Vithanage <wathsala.vithanage@arm.com> wrote:
> > > >
> > > >> MCS lock is broken, it's just a matter of time it will run into a deadlock.
> > > >>
> > > >> drivers/dma/cnxk is a user of MCS lock.
> > > > I am surprised that a driver would use mcslock.
> > > > MCSlock is targeted at case of large number of CPU's with lots of
> contention.
> > > > It will likely be slower than spinlock or ticketlock for the use case of driver.
> > > It appears in |drivers/dma/cnxk/cnxk_dmadev_fp.c|, perhaps the
> > > maintainer can clarify.
> > >
> >
> > If MCS lock is really broken, it needs to be fixed anyway.
> > It might be used by other third-party libs/apps that do use on DPDK.
> 
> 100% agree it must be fixed.
> It would be good to have test or static analysis tool that could validate all the lock
> types.

+1
Another option would be to have sort of stress test for all locking types we have in our UT.
At least for ring I found it very useful.


  parent reply	other threads:[~2025-11-04  8:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-23 18:47 Wathsala Vithanage
2025-11-03 15:12 ` Wathsala Vithanage
2025-11-03 17:07   ` Stephen Hemminger
2025-11-03 17:30     ` Wathsala Vithanage
2025-11-03 18:06       ` Konstantin Ananyev
2025-11-03 18:47         ` Wathsala Vithanage
2025-11-03 18:48         ` Stephen Hemminger
2025-11-03 19:13           ` Wathsala Vithanage
2025-11-04  8:18           ` Konstantin Ananyev [this message]
2025-11-03 23:48 ` Stephen Hemminger

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