From: Tony Lindgren > Sent: 11 May 2023 07:49 > > * Geert Uytterhoeven <geert+renesas@xxxxxxxxx> [230510 13:23]: > > It is considered good practice to call cpu_relax() in busy loops, see > > Documentation/process/volatile-considered-harmful.rst. This can not > > only lower CPU power consumption or yield to a hyperthreaded twin > > processor, but also allows an architecture to mitigate hardware issues > > (e.g. ARM Erratum 754327 for Cortex-A9 prior to r2p0) in the > > architecture-specific cpu_relax() implementation. Don't you also need to call cond_resched() (at least some times). Otherwise the process can't be pre-empted and a RT process that last ran on that cpu will never be scheduled. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
