On Tue, Jul 16, 2002, Muli Ben-Yehuda wrote about "Re: device files implementing mmap": > It's not if you use the double buffer, since you always get old but > correct data. If you use a single buffer, you might get garbage > (you're reading a chunk, and as you read it, it gets overwritten by > the kernel).
I suggested a way to solve this: your driver will refuse to overwrite the last returned chunk (it knows what it returned last!) and start dropping new data (it's a bit harder to drop old data in this scenario, but probably doable with a bit of cleverness) when the beginning of that chunk is reached again. But as you said, I doubt the zero-copy is very important (performance-wise) in this case anyway, so you might just want to stay with your existing read() interface. Remember that each small junk of your log results from a relatively slow "syscall tracking", so I doubt the copying of that data will have a huge impact on the machine's performance. -- Nadav Har'El | Tuesday, Jul 16 2002, 7 Av 5762 [EMAIL PROTECTED] |----------------------------------------- Phone: +972-53-245868, ICQ 13349191 |Hi! I'm a signature virus! Copy me into http://nadav.harel.org.il |your signature to help me spread! ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
