On 08.04.2014 14:21, Peter Zijlstra wrote: > On Mon, Apr 07, 2014 at 08:56:58PM +0200, Peter Zijlstra wrote: >> On Mon, Apr 07, 2014 at 08:16:24PM +0200, Toralf Förster wrote: >> >>> v3.14-10353-g2b3a8fd works fine AFAICS >>> (BTW the fix is stable material, right ?) >> >> I'm fairly sure its not; its a rather invasive series; see: >> >> 2432e1364bbe x86: Nuke the supervisor_stack field in i386 thread_info >> b807902a88c4 x86: Nuke GET_THREAD_INFO_WITH_ESP() macro for i386 >> 0788aa6a23cb x86: Prepare removal of previous_esp from i386 thread_info >> structure >> 198d208df437 x86: Keep thread_info on thread stack in x86_32 >> >> Let me see if there's anything 'simpler' we can stuff in .13+ > > OK.. so could someone test the below patch to see if that makes things > work for .13 and .14?
Hi Peter, sorry I only had time to try 3.13 but that looks good. I was able to get kvm up and running for a longer than usual (without the patch) amount of time without seeing any softlockups. -Stefan > > --- > arch/x86/include/asm/preempt.h | 11 +++++++++++ > include/linux/preempt.h | 4 ++++ > include/linux/thread_info.h | 2 -- > 3 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h > index c8b051933b1b..7ada46d8d4d8 100644 > --- a/arch/x86/include/asm/preempt.h > +++ b/arch/x86/include/asm/preempt.h > @@ -5,6 +5,17 @@ > #include <asm/percpu.h> > #include <linux/thread_info.h> > > +#ifdef CONFIG_X86_32 > +/* > + * i386's current_thread_info() depends on ESP and for interrupt/exception > + * stacks this doesn't yield the actual task thread_info. > + * > + * We hard rely on the fact that all the TIF_NEED_RESCHED bits are > + * the same, therefore use the slightly more expensive version below. > + */ > +#define tif_need_resched() test_tsk_thread_flag(current, TIF_NEED_RESCHED) > +#endif > + > DECLARE_PER_CPU(int, __preempt_count); > > /* > diff --git a/include/linux/preempt.h b/include/linux/preempt.h > index de83b4eb1642..891c8f8b52fe 100644 > --- a/include/linux/preempt.h > +++ b/include/linux/preempt.h > @@ -17,6 +17,10 @@ > > #include <asm/preempt.h> > > +#ifndef tif_need_resched > +#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED) > +#endif > + > #if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER) > extern void preempt_count_add(int val); > extern void preempt_count_sub(int val); > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h > index fddbe2023a5d..a629e4b23217 100644 > --- a/include/linux/thread_info.h > +++ b/include/linux/thread_info.h > @@ -118,8 +118,6 @@ static inline __deprecated void set_need_resched(void) > */ > } > > -#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED) > - > #if defined TIF_RESTORE_SIGMASK && !defined HAVE_SET_RESTORE_SIGMASK > /* > * An arch can define its own version of set_restore_sigmask() to get the >
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