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Date:   Wed, 26 Jan 2022 10:08:43 +0100 (CET)
From:   Richard Weinberger <richard@nod.at>
To:     David Decotigny <decot+git@google.com>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-mtd <linux-mtd@lists.infradead.org>,
        David Decotigny <ddecotig@google.com>
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In-Reply-To: <20220126085735.575625-1-decot+git@google.com>
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Subject: Re: [PATCH RFC v1 1/1] mtd_blkdevs: avoid soft lockups with some
 mtd/spi devices
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Thread-Topic: mtd_blkdevs: avoid soft lockups with some mtd/spi devices
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David,

----- Ursprüngliche Mail -----
> Von: "David Decotigny" <decot+git@google.com>
> An: "linux-kernel" <linux-kernel@vger.kernel.org>
> CC: "Miquel Raynal" <miquel.raynal@bootlin.com>, "richard" <richard@nod.at>, "Vignesh Raghavendra" <vigneshr@ti.com>,
> "linux-mtd" <linux-mtd@lists.infradead.org>, "David Decotigny" <ddecotig@google.com>
> Gesendet: Mittwoch, 26. Januar 2022 09:57:35
> Betreff: [PATCH RFC v1 1/1] mtd_blkdevs: avoid soft lockups with some mtd/spi devices

> From: David Decotigny <ddecotig@google.com>
> 
> With some spi devices, the heavy cpu usage due to polling the spi
> registers may lead to netdev timeouts, RCU complaints, etc. This can
> be acute in the absence of CONFIG_PREEMPT. This patch allows to give
> enough breathing room to avoid those false positives.

is the problem real or not? From your description it is not clear to me.
Please include lockdep splats and/or hung-task logs in the commit message.

I have no problem with adding a cond_resched() but first we need to
understand the issue a little better.

Thanks,
//richard