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Groups > linux.kernel > #1542916
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [patch 1/3] x86/process: Optimize TIF checks in switch_to_extra() |
| Date | 2016-12-15 18:30 +0100 |
| Message-ID | <sOI0W-9O-11@gated-at.bofh.it> (permalink) |
| References | <sOHoe-87a-13@gated-at.bofh.it> <sOHoe-87a-37@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Dec 15, 2016 at 04:44:02PM -0000, Thomas Gleixner wrote:
> void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
> struct tss_struct *tss)
> {
> struct thread_struct *prev, *next;
> + unsigned long tifp, tifn;
>
> prev = &prev_p->thread;
> next = &next_p->thread;
>
> + tifn = task_thread_info(next_p)->flags;
> + tifp = task_thread_info(prev_p)->flags;
> + switch_to_bitmap(tss, prev, next, tifp, tifn);
> +
> + propagate_user_return_notify(prev_p, next_p);
> +
> + if ((tifp ^ tifn) & _TIF_BLOCKSTEP) {
> unsigned long debugctl = get_debugctlmsr();
>
> debugctl &= ~DEBUGCTLMSR_BTF;
> + if (tifn & _TIF_BLOCKSTEP)
> debugctl |= DEBUGCTLMSR_BTF;
> update_debugctlmsr(debugctl);
> }
Going by the toggle patter you have elsewhere, wouldn't that then be:
if ((tifp ^ tifn) & _TIF_BLOCKSTEP) {
unsigned long debugctl = get_debugctlmsr();
debugctl ^= DEBUGCTLMSR_BTF;
update_debugctlmsr(debugctl);
}
?
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[patch 0/3] x86/process: Optimize __switch_to_extra() Thomas Gleixner <tglx@linutronix.de> - 2016-12-15 17:50 +0100
[patch 2/3] x86/process: Optimize TIF_BLOCKSTEP switch Thomas Gleixner <tglx@linutronix.de> - 2016-12-15 17:50 +0100
Re: [patch 2/3] x86/process: Optimize TIF_BLOCKSTEP switch Andy Lutomirski <luto@amacapital.net> - 2016-12-15 18:30 +0100
Re: [patch 2/3] x86/process: Optimize TIF_BLOCKSTEP switch Thomas Gleixner <tglx@linutronix.de> - 2016-12-16 10:00 +0100
Re: [patch 2/3] x86/process: Optimize TIF_BLOCKSTEP switch Andy Lutomirski <luto@amacapital.net> - 2016-12-16 20:30 +0100
[patch 1/3] x86/process: Optimize TIF checks in switch_to_extra() Thomas Gleixner <tglx@linutronix.de> - 2016-12-15 17:50 +0100
Re: [patch 1/3] x86/process: Optimize TIF checks in switch_to_extra() Thomas Gleixner <tglx@linutronix.de> - 2016-12-15 18:30 +0100
Re: [patch 1/3] x86/process: Optimize TIF checks in switch_to_extra() Peter Zijlstra <peterz@infradead.org> - 2016-12-15 18:40 +0100
Re: [patch 1/3] x86/process: Optimize TIF checks in switch_to_extra() Andy Lutomirski <luto@amacapital.net> - 2016-12-15 18:30 +0100
Re: [patch 1/3] x86/process: Optimize TIF checks in switch_to_extra() Peter Zijlstra <peterz@infradead.org> - 2016-12-15 18:30 +0100
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