lkml.org 
[lkml]   [2011]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: RFC: android logger feedback request
On Wed, Dec 21, 2011 at 04:18:11PM -0800, john stultz wrote:
> 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.

That sounds like a major overlap, can't pstore be used for this
functionality today instead of the logger code?

greg k-h


\
 
 \ /
  Last update: 2011-12-22 01:29    [W:0.704 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site