Subject: Re: [PATCH 2/2] powerpc: tm: Enable transactional memory (TM) lazily for userspace

From: Simon Guo <[email-masked]>
Date: Mon, 19 Sep 2016 12:47:19 +0800

On Wed, Sep 14, 2016 at 06:02:16PM +1000, Cyril Bur wrote:
> @@ -954,8 +963,16 @@ static inline void __switch_to_tm(struct task_struct *prev,
>  		struct task_struct *new)
>  {
>  	if (cpu_has_feature(CPU_FTR_TM)) {
> -		tm_enable();
> -		tm_reclaim_task(prev);
> +		if (tm_enabled(prev) || tm_enabled(new))
> +			tm_enable();
> +
> +		if (tm_enabled(prev)) {
> +			prev->thread.load_tm++;
> +			tm_reclaim_task(prev);
> +			if (!MSR_TM_ACTIVE(prev->thread.regs->msr) && prev->thread.load_tm == 0)
> +				prev->thread.regs->msr &= ~MSR_TM;
> +		}
Hi Cyril,

If MSR_TM_ACTIVE(), is it better to reset load_tm to 0?
Other looks good to me.

Thanks,
- Simon