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Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async

From Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Newsgroups linux.kernel
Subject Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async
Date 2016-03-22 07:00 +0100
Message-ID <rfnwe-8uo-3@gated-at.bofh.it> (permalink)
References (5 earlier) <rf2Bs-2nn-5@gated-at.bofh.it> <rf34u-2NK-15@gated-at.bofh.it> <rf3Hb-337-13@gated-at.bofh.it> <rf4jT-3xO-1@gated-at.bofh.it> <rfk5j-6bs-11@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On (03/22/16 11:13), Byungchul Park wrote:
[..]

what about a "normal" case, when things are not going to explode printk(),
but we have several lockups on the same lock (which is probably more
likely than printk recursion)?

suppose:
- there are 8 CPUs on the system
- 1 cpus owns the spin_lock for too long
- 4 cpus are trying to lock the spin_lock w/o any success
- so all 4 trigger spin_dump.

what we have at the moment, is that all 4 CPUs will report a lockup,
but with this static pointer only X (between 1 and 4, depending on the
timing; on how fast spin_dump() will return (logbuf lock can
be busy for a while); etc.) CPUs will do so.

	-ss

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[RFC][PATCH v5 0/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-20 15:20 +0100
  [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-20 15:20 +0100
    Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-21 01:10 +0100
      Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-21 01:50 +0100
        Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-21 02:00 +0100
          Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-21 08:40 +0100
            Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-21 09:10 +0100
              Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-21 09:50 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-21 10:30 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Jan Kara <jack@suse.cz> - 2016-03-21 15:40 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-21 16:10 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Jan Kara <jack@suse.cz> - 2016-03-21 16:40 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-21 18:20 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-22 03:20 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-22 03:20 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-22 07:00 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Byungchul Park <byungchul.park@lge.com> - 2016-03-22 08:00 +0100
                Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-22 08:50 +0100
              Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-03-21 10:00 +0100
  [RFC][PATCH v5 2/2] printk: Make wake_up_klogd_work_func() async Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-03-20 15:20 +0100

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