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    SubjectRe: RFC: android logger feedback request
    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:
    > >
    > > 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.


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