From: John Ogness <john.ogness@linutronix.de>
To: David Laight <David.Laight@ACULAB.COM>,
'Joe Perches' <joe@perches.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [RFC PATCH 1/5] printk: implement pr_cont_t
Date: Thu, 20 Aug 2020 11:24:33 +0206 [thread overview]
Message-ID: <87wo1tzndi.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <389a62f178d2482b9525f499b82e92df@AcuMS.aculab.com>
On 2020-08-20, David Laight <David.Laight@ACULAB.COM> wrote:
>> On Thu, 2020-08-20 at 07:44 +0000, David Laight wrote:
>>> I've no idea how you'd 'size' the number of buffers.
>>
>> I believe they are static and assume no more than 10
>> simultaneous uses of printk_begin
>
> What I meant was how you'd work out whether 10 was in any way
> appropriate. ISTM it is either 'too many' or 'nowhere near enough'
> depending on exactly what the system is doing.
Right now mainline has 1, which breaks pr_cont just booting your system.
I expect we will be increasing the number of buffers, regardless if we
adapt a new API or continue with what we have now.
> And if code 'leaks' them you are in deep doo-doos.
Not really. It falls back to printing individual parts. Also, the printk
subsystem has access to the open buffers and could even track the users
lockdep style.
But this discussion has little to do with the API. These are
implementation details that may end up under the hood of the current
mainline API.
John Ogness
next prev parent reply other threads:[~2020-08-20 9:19 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 23:26 [RFC PATCH 0/5] printk: new log_cont implementation John Ogness
2020-08-19 23:26 ` [RFC PATCH 1/5] printk: implement pr_cont_t John Ogness
2020-08-20 0:33 ` Joe Perches
2020-08-20 7:44 ` David Laight
2020-08-20 7:59 ` Joe Perches
2020-08-20 8:49 ` David Laight
2020-08-20 9:18 ` John Ogness [this message]
2020-08-20 16:03 ` Joe Perches
2020-08-20 10:16 ` Petr Mladek
2020-08-20 12:33 ` David Laight
2020-08-25 13:10 ` Petr Mladek
2020-08-25 13:38 ` David Laight
2020-08-25 15:32 ` Petr Mladek
2020-08-24 2:08 ` Sergey Senozhatsky
2020-08-24 5:37 ` Sergey Senozhatsky
2020-08-19 23:26 ` [RFC PATCH 2/5] sysrq: use pr_cont_t for cont messages John Ogness
2020-08-20 1:03 ` Linus Torvalds
2020-08-20 17:48 ` Joe Perches
2020-08-20 17:53 ` Linus Torvalds
2020-08-20 22:11 ` John Ogness
2020-08-20 22:36 ` Joe Perches
2020-08-19 23:26 ` [RFC PATCH 3/5] workqueue: " John Ogness
2020-08-19 23:26 ` [RFC PATCH 4/5] locking/selftest: " John Ogness
2020-08-19 23:26 ` [RFC PATCH 5/5] lockdep: " John Ogness
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