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 -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
