From: Robert Love <rml@tech9.net> To: linux-kernel@vger.kernel.org Subject: [PATCH] preemptible kernel patch for 2.4 and 2.5 Date: 07 Jan 2002 13:16:58 -0500 Cc: kpreempt-tech@lists.sourceforge.net Announcing the next revision of the fully preemptible linux kernel patch, available for 2.4 and 2.5 trees now at: ftp://ftp.kernel.org/pub/linux/kernel/people/rml/preempt-kernel and your favorite mirrors. Diffs for 2.4.18-pre1 and 2.5.2-pre9 are available along with previous patches. This patch, which we are all familiar with by now, makes the kernel preemptible. This means that a higher priority process can preempt a lower priority process, even if it is running inside the kernel. Reentrancy is protected by SMP lock points. Despite the warnings to the contrary about throughput, benchmarking actually shows a marked increase, probably due to faster scheduling of woken I/O tasks. Complexity added is minimal. ARM, i386, and SH are supported. UP and SMP is supported. There are no outstanding bugs. Perhaps a feature that is often overlooked is the growth for performance gains in the future. As we continue to make locks finer grained (and, especially, remove the BKL) performance will increase. Thus we now have an architecture where by we can continue to improve performance. Changes: - (2.5 only) include linux/sched.h in fs/char_dev.c - SH arch: fix certain code path not hitting preempt_enable (Jeremy Siegel) - stop locking task to CPU across preemptions. - back out console race fix as it was merged with mainline Todo: - Port the scheduling details to Ingo's O(1) scheduler Enjoy, Robert Love - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/