From 65e31d7b980c1413f19fcb84234387f97b09588f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 1 Nov 2012 10:14:11 +0100 Subject: [PATCH 37/62] powerpc: Add support for lazy preemption Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.1/older/patches-6.1.69-rt21.tar.xz Implement the powerpc pieces for lazy preempt. Signed-off-by: Thomas Gleixner --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/thread_info.h | 8 ++++++++ arch/powerpc/kernel/interrupt.c | 8 ++++++-- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 6050e6e10d32..0eff864d6ec3 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -242,6 +242,7 @@ config PPC select HAVE_PERF_EVENTS_NMI if PPC64 select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_PREEMPT_LAZY select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RELIABLE_STACKTRACE select HAVE_RSEQ diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index af58f1ed3952..520864de8bb2 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -53,6 +53,8 @@ struct thread_info { int preempt_count; /* 0 => preemptable, <0 => BUG */ + int preempt_lazy_count; /* 0 => preemptable, + <0 => BUG */ #ifdef CONFIG_SMP unsigned int cpu; #endif @@ -77,6 +79,7 @@ struct thread_info { #define INIT_THREAD_INFO(tsk) \ { \ .preempt_count = INIT_PREEMPT_COUNT, \ + .preempt_lazy_count = 0, \ .flags = 0, \ } @@ -102,6 +105,7 @@ void arch_setup_new_exec(void); #define TIF_PATCH_PENDING 6 /* pending live patching update */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SINGLESTEP 8 /* singlestepping active */ +#define TIF_NEED_RESCHED_LAZY 9 /* lazy rescheduling necessary */ #define TIF_SECCOMP 10 /* secure computing */ #define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */ #define TIF_NOERROR 12 /* Force successful syscall return */ @@ -117,6 +121,7 @@ void arch_setup_new_exec(void); #define TIF_POLLING_NRFLAG 19 /* true if poll_idle() is polling TIF_NEED_RESCHED */ #define TIF_32BIT 20 /* 32 bit binary */ + /* as above, but as bit values */ #define _TIF_SYSCALL_TRACE (1<msr & MSR_EE)); again: - if (IS_ENABLED(CONFIG_PREEMPT)) { + if (IS_ENABLED(CONFIG_PREEMPTION)) { /* Return to preemptible kernel context */ if (unlikely(read_thread_flags() & _TIF_NEED_RESCHED)) { if (preempt_count() == 0) preempt_schedule_irq(); + } else if (unlikely(current_thread_info()->flags & _TIF_NEED_RESCHED_LAZY)) { + if ((preempt_count() == 0) && + (current_thread_info()->preempt_lazy_count == 0)) + preempt_schedule_irq(); } } -- 2.43.0