From: john stultz <johnstul@us.ibm.com>
To: Greg KH <gregkh@suse.de>
Cc: Tim Bird <tim.bird@am.sony.com>,
linux-embedded <linux-embedded@vger.kernel.org>,
linux kernel <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Brian Swetland <swetland@google.com>,
Kay Sievers <kay.sievers@vrfy.org>,
Lennart Poettering <lennart@poettering.net>
Subject: Re: RFC: android logger feedback request
Date: Wed, 21 Dec 2011 16:18:11 -0800 [thread overview]
Message-ID: <1324513091.30527.139.camel@work-vm> (raw)
In-Reply-To: <20111221231956.GB23859@suse.de>
On Wed, 2011-12-21 at 15:19 -0800, Greg KH wrote:
> On Wed, Dec 21, 2011 at 02:59:15PM -0800, Tim Bird wrote:
> > Hi all,
> >
> > I'm looking for feedback on the Android logger code, to see what
> > it would take to make this code acceptable for inclusion in
> > the mainline kernel.
> >
> > Information about the features of Android logging system
> > can be found at: http://elinux.org/Android_Logging_System
> >
> > This system creates a new system-wide logging service, in
> > the kernel, for user-space message. It is more comparable
> > to syslog than to the kernel log buffer, as it holds only
> > user-space messages. It is optimized for write
> > performance, since most of the time the log is written to
> > and never read. It creates multiple log channels, to prevent
> > an abundance of log messages in one channel from overwriting
> > messages in another channel. The log channels have sizes
> > fixed at kernel compile-time.
> >
> > Log messages are stored in very simple in-kernel buffers, that
> > overflow old messages upon wrapping. A fixed set of attributes
> > (pid, tid, timestamp and message), is kept for each message.
> > By convention, Android puts a message priority and context tag
> > into each message.
> >
> > In Android, this system uses a fixed set of device nodes with
> > well-known names: /dev/log/main, /dev/log/events, /dev/log/radio
> > and /dev/log/system.
> >
> > Operations on the log are done via a character device, using
> > standard file operations and some ioctls.
> >
> > The code for this is below (I've moved it from linux-next
> > drivers/staging/android for my own testing).
> >
> > Please let me know what issues you see with this code.
>
> That all describes the current code, but you haven't described what's
> wrong with the existing syslog interface that requires this new driver
> to be written. And why can't the existing interface be fixed to address
> these (potential) shortcomings?
>
> > One specific question I have is where is the most appropriate
> > place for this code to live, in the kernel source tree?
> > Other embedded systems might want to use this system (it
> > is simpler than syslog, and superior in some ways), so I don't
> > think it should remain in an android-specific directory.
>
> What way is it superior? Again, why not extend syslog? Why not "fix"
> syslog if this really is a superior thing? How does this tie into Kay
> and Lennard's proposal for work in this area?
There is also some overlap functionality wise with pstore as well, as I
believe the logger is used as a known location in memory where messages
can be fetched from after a kernel panic or crash.
thanks
-john
next prev parent reply other threads:[~2011-12-22 0:18 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 22:59 RFC: android logger feedback request Tim Bird
2011-12-21 23:19 ` Greg KH
2011-12-22 0:18 ` john stultz [this message]
2011-12-22 0:27 ` Greg KH
2011-12-22 0:47 ` john stultz
2011-12-22 1:09 ` john stultz
2011-12-22 0:42 ` Tim Bird
2011-12-22 0:49 ` john stultz
2011-12-22 1:00 ` john stultz
2011-12-22 0:36 ` Tim Bird
2011-12-22 0:51 ` Greg KH
2011-12-22 1:32 ` Tim Bird
2011-12-22 1:47 ` Greg KH
2011-12-22 2:12 ` Tim Bird
2011-12-22 3:44 ` Kay Sievers
2011-12-22 3:45 ` Greg KH
2011-12-22 3:47 ` Greg KH
2011-12-22 4:12 ` Kay Sievers
2011-12-22 4:22 ` Brian Swetland
2011-12-22 4:43 ` Kay Sievers
2011-12-22 4:47 ` david
2011-12-22 4:58 ` Brian Swetland
2011-12-22 5:07 ` david
2011-12-22 5:21 ` david
2011-12-22 13:40 ` Lennart Poettering
2011-12-22 4:49 ` david
2011-12-22 2:34 ` Kay Sievers
2011-12-22 1:20 ` NeilBrown
2011-12-22 1:49 ` Greg KH
2011-12-22 2:14 ` Tim Bird
2011-12-22 2:34 ` Brian Swetland
2011-12-22 3:49 ` Greg KH
2011-12-22 4:36 ` Kay Sievers
2011-12-22 5:01 ` david
2011-12-22 4:52 ` david
2011-12-22 5:06 ` Brian Swetland
2011-12-22 5:14 ` david
2011-12-22 5:25 ` Brian Swetland
2011-12-22 6:09 ` Greg KH
2011-12-23 15:22 ` Alan Cox
2011-12-23 16:29 ` Greg KH
2011-12-22 7:05 ` NeilBrown
2012-01-06 20:56 ` Tim Bird
2012-01-06 21:20 ` Greg KH
2012-01-06 22:41 ` Tim Bird
2012-01-06 23:17 ` Greg KH
2012-01-06 23:35 ` Greg KH
2011-12-22 14:59 ` Arnd Bergmann
2011-12-22 15:13 ` Kay Sievers
2011-12-22 4:42 ` david
2011-12-22 0:59 ` David Brown
2011-12-29 0:39 ` Andrew Morton
2012-01-04 15:34 ` Geunsik Lim
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