Here is a respin of the task-isolation patch set. This primarily reflects feedback from Frederic and Peter Z. Changes since v12: - Rebased on v4.7-rc7. - New default "strict" model for task isolation - tasks exit the kernel from the initial prctl() to userspace, and can only legally exit by calling prctl() again to turn off isolation. Any other kernel entry results in a SIGKILL by default. - New optional "relaxed" mode, where the application can receive some signal other than SIGKILL, or no signal at all, when it re-enters the kernel. Since by default task isolation is now strict, there is no longer an additional "STRICT" mode, but rather a new "NOSIG" mode that builds on top of the "USERSIG" support for setting a signal other than SIGKILL to be delivered to the process. The "NOSIG" mode also relaxes the required criteria for entering task isolation mode; we just issue a warning if the affinity isn't set right, and we don't fail with EAGAIN if the kernel isn't ready to stop the tick. Running your task-isolation application in this "NOSIG" mode is also necessary when debugging, since otherwise hitting breakpoints, etc., will cause a fatal signal to be sent to the process. Frederic has suggested we might want to defer this functionality until later, but (in addition to the debuggability aspect) there is some thought that it might be useful for e.g. HPC, so I have just broken out the additional semantics into a single separate patch at the end of the series. - Function naming has been changed and comments have been added to try to clarify the role of the task-isolation reporting on kernel entries that do NOT cause signals. This hopefully clarifies why we only invoke the renamed task_isolation_quiet_exception() in a few places, since all the other places generate signals anyway. [PeterZ] - The task_isolation_debug() call now has an inline piece that checks to see if the target is a task_isolation cpu before actually calling. [PeterZ] - In _task_isolation_debug(), we use the new task_struct_trylock() call that is in linux-next now; for now I just have a static copy of the function, which I will switch to using the version from linux-next in the next rebasing. [PeterZ] - We now pass a string describing the interrupt up from task_isolation_debug() so there is more information on where the interrupt came from beyond just the stack backtrace. [PeterZ] - I added task_isolation_debug() hooks to smp_sched_reschedule() on x86, which was missing before, and removed the hooks in the tile send_IPI_*() routines, since there were already hooks in the callers. Likewise I moved the hook for arm64 from the generic smp_cross_call() routine to the only caller that wasn't already hooked, smp_send_reschedule(). The commit message clarifies the rationale for where hooks are placed. - I moved the page fault reporting so that it only reports in the case that we are not also sending a SIGSEGV/SIGBUS, for consistency with other uses of task_isolation_quiet_exception(). The previous (v12) patch series is here: https://lkml.kernel.org/g/1459877922-15512-1-git-send-email-cmetcalf@xxxxxxxxxxxx This version of the patch series has been tested on arm64 and tilegx, and build-tested on x86. It remains true that the 1 Hz tick needs to be disabled for this patch series to be able to achieve its primary goal of enabling truly tick-free operation, but that is ongoing orthogonal work. Frederick, do you have a sense of what is left to be done there? I can certainly try to contribute to that effort as well. The series is available at: git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile.git dataplane Chris Metcalf (12): vmstat: add quiet_vmstat_sync function vmstat: add vmstat_idle function lru_add_drain_all: factor out lru_add_drain_needed task_isolation: add initial support task_isolation: track asynchronous interrupts arch/x86: enable task isolation functionality arm64: factor work_pending state machine to C arch/arm64: enable task isolation functionality arch/tile: enable task isolation functionality arm, tile: turn off timer tick for oneshot_stopped state task_isolation: support CONFIG_TASK_ISOLATION_ALL task_isolation: add user-settable notification signal Documentation/kernel-parameters.txt | 16 ++ arch/arm64/Kconfig | 1 + arch/arm64/include/asm/thread_info.h | 5 +- arch/arm64/kernel/entry.S | 12 +- arch/arm64/kernel/ptrace.c | 15 +- arch/arm64/kernel/signal.c | 42 +++- arch/arm64/kernel/smp.c | 2 + arch/arm64/mm/fault.c | 8 +- arch/tile/Kconfig | 1 + arch/tile/include/asm/thread_info.h | 4 +- arch/tile/kernel/process.c | 9 + arch/tile/kernel/ptrace.c | 7 + arch/tile/kernel/single_step.c | 7 + arch/tile/kernel/smp.c | 26 +-- arch/tile/kernel/time.c | 1 + arch/tile/kernel/unaligned.c | 4 + arch/tile/mm/fault.c | 13 +- arch/tile/mm/homecache.c | 2 + arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 18 +- arch/x86/include/asm/thread_info.h | 2 + arch/x86/kernel/smp.c | 2 + arch/x86/kernel/traps.c | 3 + arch/x86/mm/fault.c | 5 + drivers/base/cpu.c | 18 ++ drivers/clocksource/arm_arch_timer.c | 2 + include/linux/context_tracking_state.h | 6 + include/linux/isolation.h | 73 +++++++ include/linux/sched.h | 3 + include/linux/swap.h | 1 + include/linux/tick.h | 2 + include/linux/vmstat.h | 4 + include/uapi/linux/prctl.h | 10 + init/Kconfig | 37 ++++ kernel/Makefile | 1 + kernel/fork.c | 3 + kernel/irq_work.c | 5 +- kernel/isolation.c | 337 +++++++++++++++++++++++++++++++++ kernel/sched/core.c | 42 ++++ kernel/signal.c | 15 ++ kernel/smp.c | 6 +- kernel/softirq.c | 33 ++++ kernel/sys.c | 9 + kernel/time/tick-sched.c | 36 ++-- mm/swap.c | 15 +- mm/vmstat.c | 19 ++ 46 files changed, 827 insertions(+), 56 deletions(-) create mode 100644 include/linux/isolation.h create mode 100644 kernel/isolation.c -- 2.7.2 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
