2014-10-02 10:01 GMT-07:00 Clemens Gruber <clemens.gruber@xxxxxxxxxxxx>: > Hi, > > I am just trying to solve a similar problem as Luca described. I have a > TQMa28 board running Linux 3.17-rc7 though. > The capacitors keep the system up for about 1500 more milliseconds after > the power fails. A GPIO line is set to high as soon as the main power is > lost. > > So I have not much time to quit an important user space process and to > clean up the ext4 root filesystem before the power fails. > > At the moment I pass rootflags=data=journal,commit=1 in the kernel > commandline to lower the risk of data loss. > In the user space application I open important files using the O_SYNC flag. > > Is there something else I should do to avoid data loss? > > How would you implement the "emergency cleanup on power-failure" logic? > Dedicated driver (similar to the mentioned gpio-event driver?), > implement it with UIO, let a userspace application running as root > select /dev/uioX and cleaning up? how about using netlink to notify the usersapce app on gpio interrupt . > > Or should I create a separate partition on my eMMC just for this user > space application data and use a readonly rootfs for the rest? > > Thanks for your help! > > Best regards, > Clemens > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
