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Groups > linux.kernel > #1722983
| From | Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: printk: what is going on with additional newlines? |
| Date | 2017-08-30 04:50 +0200 |
| Message-ID | <uk1eN-2wZ-3@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <ujZG1-1EU-9@gated-at.bofh.it> <ujZPH-1HW-7@gated-at.bofh.it> <uk0sp-1Us-1@gated-at.bofh.it> <uk0Vr-2px-1@gated-at.bofh.it> <uk157-2sK-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On (08/29/17 19:31), Joe Perches wrote:
[..]
> > the idea is not to do printk() on that seq buffer at all, but to
> > log_store(), atomically, seq buffer messages
> >
> > spin_lock(&logbuf_lock)
> > while (offset < seq_buffer->len) {
> > ...
> > log_store(seq->buffer + offset);
> > ...
> > }
> > spin_unlock(&logbuf_unlock)
>
> Why?
>
> What's wrong with a simple printk?
> It'd still do a log_store.
sure, it will. but in separate logbuf entries, and between two
consequent printk calls on the same CPU a lot of stuff can happen:
IRQs->printks, rescheduling->printks, etc. etc. (not to mention
concurrent printks from other CPUs) so what people want to have is
to have a way to make several printks appear next to each other in
the logs (dmesg or serial log). Tetsuo wants this, for instance,
for OOM reports and backtraces. SCIS/ATA people want it as well.
-ss
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printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-28 11:10 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 12:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 14:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 14:40 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-28 14:50 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-29 15:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 18:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:10 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:20 +0200
Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-08-29 22:50 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 23:00 +0200
Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-09-02 08:20 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-02 19:10 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-08-30 02:00 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-30 02:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:10 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-08-30 03:20 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 04:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 04:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 04:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 04:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 05:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 07:40 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-08 12:20 +0200
Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-05 11:50 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-05 12:10 +0200
Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-05 14:30 +0200
Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-09-05 14:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-09-05 16:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-05 15:50 +0200
Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-06 10:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-09-01 15:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 19:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-01 22:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 07:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-04 07:50 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-09-05 17:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-06 04:20 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-06 04:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 06:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 07:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-08-29 19:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 20:00 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 20:10 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:10 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:00 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 18:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:20 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:40 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:50 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-29 22:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-01 03:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 04:10 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-01 09:00 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 09:30 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-01 09:30 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-09-01 13:20 +0200
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