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Groups > linux.kernel > #1542915
| From | Andy Lutomirski <luto@amacapital.net> |
|---|---|
| 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-25@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 8:44 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> - if (test_tsk_thread_flag(prev_p, TIF_BLOCKSTEP) ^
> - test_tsk_thread_flag(next_p, TIF_BLOCKSTEP)) {
> + tifn = task_thread_info(next_p)->flags;
> + tifp = task_thread_info(prev_p)->flags;
Minor nit, but I think that a sufficiently clever compiler could
interpret this to mean "no one else is modifying these flags, so I can
do clever crazy things". Wrapping these in READ_ONCE might be
helpful.
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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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