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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist_head
Date: Sat, 23 Jan 2021 21:10:24 +0100
Message-ID: <20210123201027.3262800-1-bigeasy@linutronix.de> (raw)

Patch 2+3 were applied and then dropped by Jens due to a NOHZ+softirq
related warning [0]. Turns out a successful wakeup via
set_nr_if_polling() will not process any softirqs and the CPU may go
back to idle. This is addressed by patch #1.

smpcfd_dying_cpu() will also invoke SMP-functions calls via
flush_smp_call_function_queue() but the block layer shouldn't queue
anything because the CPU isn't online anymore.
The two caller of flush_smp_call_function_from_idle() look fine with
opening interrupts from within do_softirq().

[0] https://lkml.kernel.org/r/1ee4b31b-350e-a9f5-4349-cfb34b89829a@kernel.dk

Sebastian



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Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-23 20:10 Sebastian Andrzej Siewior [this message]
2021-01-23 20:10 ` [PATCH 1/3] smp: Process pending softirqs in flush_smp_call_function_from_idle() Sebastian Andrzej Siewior
2021-02-01 19:35   ` Sebastian Andrzej Siewior
2021-02-09 10:02   ` Peter Zijlstra
2021-02-09 11:35     ` Sebastian Andrzej Siewior
2021-01-23 20:10 ` [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq Sebastian Andrzej Siewior
2021-01-25  7:10   ` Hannes Reinecke
2021-01-25  8:25     ` Christoph Hellwig
2021-01-25  8:30       ` Sebastian Andrzej Siewior
2021-01-25  8:32         ` Christoph Hellwig
2021-01-25  9:29           ` Sebastian Andrzej Siewior
2021-01-25  8:22   ` Christoph Hellwig
2021-01-25  8:49     ` Christoph Hellwig
2021-01-27 11:22   ` Daniel Wagner
2021-01-23 20:10 ` [PATCH 3/3] blk-mq: Use llist_head for blk_cpu_done Sebastian Andrzej Siewior
2021-01-25  8:30   ` Christoph Hellwig
2021-01-25  8:32     ` Sebastian Andrzej Siewior
2021-01-25  8:39       ` Christoph Hellwig
2021-01-25  9:54         ` [PATCH 3/3 v2] " Sebastian Andrzej Siewior
2021-01-25 10:14           ` Christoph Hellwig
2021-01-27 11:23           ` Daniel Wagner
2021-01-25  4:27 ` [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist_head Jens Axboe
2021-02-10 14:43 ` Jens Axboe

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