From: Miquel Raynal <miquel.raynal@bootlin.com>
To: David Decotigny <decot+git@google.com>, linux-kernel@vger.kernel.org
Cc: Miquel Raynal <miquel.raynal@bootlin.com>,
Richard Weinberger <richard@nod.at>,
Vignesh Raghavendra <vigneshr@ti.com>,
linux-mtd@lists.infradead.org,
David Decotigny <ddecotig@google.com>
Subject: Re: [PATCH RFC v3 1/1] mtd_blkdevs: avoid soft lockups with some mtd/spi devices
Date: Wed, 26 Jan 2022 11:52:14 +0100 [thread overview]
Message-ID: <20220126105214.882348-1-miquel.raynal@bootlin.com> (raw)
In-Reply-To: <20220126101120.676021-1-decot+git@google.com>
On Wed, 2022-01-26 at 10:11:20 UTC, David Decotigny wrote:
> 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 incorrectly detected netdev
> timeouts for example.
>
> Example splat on 5.10.92:
> [ 828.399306] rcu: INFO: rcu_sched self-detected stall on CPU
> ...
> [ 828.419245] Task dump for CPU 1:
> [ 828.422465] task:kworker/1:1H state:R running task on cpu 1 stack: 0 pid: 76 ppid: 2 flags:0x0000002a
> [ 828.433132] Workqueue: kblockd blk_mq_run_work_fn
> [ 828.437820] Call trace:
> ...
> [ 828.512267] spi_mem_exec_op+0x4d0/0xde0
> [ 828.516184] spi_mem_dirmap_read+0x180/0x39c
> [ 828.520443] spi_nor_read_data+0x428/0x7e8
> [ 828.524523] spi_nor_read+0x154/0x214
> [ 828.528172] mtd_read_oob+0x440/0x714
> [ 828.531815] mtd_read+0xac/0x120
> [ 828.535030] mtdblock_readsect+0x178/0x230
> [ 828.539102] mtd_blktrans_work+0x9fc/0xf28
> [ 828.543177] mtd_queue_rq+0x1ac/0x2e4
> [ 828.546827] blk_mq_dispatch_rq_list+0x2cc/0xa44
> [ 828.551419] blk_mq_do_dispatch_sched+0xb0/0x7cc
> [ 828.556010] __blk_mq_sched_dispatch_requests+0x350/0x494
> [ 828.561372] blk_mq_sched_dispatch_requests+0xac/0xe4
> [ 828.566387] __blk_mq_run_hw_queue+0x130/0x254
> [ 828.570806] blk_mq_run_work_fn+0x50/0x60
> [ 828.574814] process_one_work+0x578/0xf1c
> [ 828.578814] worker_thread+0x5dc/0xea0
> [ 828.582547] kthread+0x270/0x2d4
> [ 828.585765] ret_from_fork+0x10/0x30
>
>
> Signed-off-by: David Decotigny <ddecotig@google.com>
> Reviewed-by: Richard Weinberger <richard@nod.at>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.
Miquel
prev parent reply other threads:[~2022-01-26 10:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-26 10:11 David Decotigny
2022-01-26 10:16 ` Richard Weinberger
2022-01-26 10:52 ` Miquel Raynal [this message]
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