linux-kernel - Re: printk meeting at LPC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190918091100.GA55364@jagdpanzerIV>
Date:   Wed, 18 Sep 2019 18:11:00 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     John Ogness <john.ogness@...utronix.de>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Petr Mladek <pmladek@...e.com>,
        Andrea Parri <parri.andrea@...il.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Brendan Higgins <brendanhiggins@...gle.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Theodore Ts'o <tytso@....edu>, Paul Turner <pjt@...gle.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Prarit Bhargava <prarit@...hat.com>
Subject: Re: printk meeting at LPC

On (09/18/19 11:05), John Ogness wrote:
> On 2019-09-18, Sergey Senozhatsky <sergey.senozhatsky.work@...il.com> wrote:
> >> Each console has its own iterator. This iterators will need to
> >> advance, regardless if the message was printed via write() or
> >> write_atomic().
> >
> > Great.
> >
> > ->atomic_write() path will make sure that kthread is parked or will
> > those compete for uart port?
> 
> A cpu-lock (probably per-console) will be used to synchronize the
> two. Unlike my RFCv1, we want to keep the cpu-lock out of the console
> drivers and we want it to be less aggressive (using trylock's instead of
> spinning).

That's my expectation as well. cpu-lock and per-console kthread can
live just fine in printk.c file.

	-ss