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Groups > linux.kernel > #1381435
| From | Xunlei Pang <xpang@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter |
| Date | 2016-04-18 11:50 +0200 |
| Message-ID | <rpdYC-3eO-9@gated-at.bofh.it> (permalink) |
| References | <rnNMR-Ww-3@gated-at.bofh.it> <rnNMS-Ww-23@gated-at.bofh.it> <rpcJc-2fT-17@gated-at.bofh.it> <rpd2x-2oe-11@gated-at.bofh.it> <rpdlU-2Qd-21@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 2016/04/18 at 17:02, Thomas Gleixner wrote: > On Mon, 18 Apr 2016, Xunlei Pang wrote: >> On 2016/04/18 at 16:23, Thomas Gleixner wrote: >>> On Thu, 14 Apr 2016, Xunlei Pang wrote: >>>> We should deboost before waking the high-prio task such that >>>> we don't run two tasks with the 'same' priority. >>> No. This is fundamentaly broken. >>> >>> T1 (prio 0) lock(X) >>> >>> --> preemption >>> >>> T2 (prio 10) lock(X) >>> boost(T1) >>> schedule() >>> >>> T1 (prio 10) unlock(X) >> We add a preempt_disable() before deboost to avoid the breakage, >> there's also some comment about this in the patch's code. > So the changelog is useless and misleading. Neither does it explain what's > wrong with having two tasks with the same priority in running state. Sorry about that, will improve it. Regards, Xunlei > > Thanks, > > tglx > > > >
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Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Thomas Gleixner <tglx@linutronix.de> - 2016-04-18 10:30 +0200
Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Xunlei Pang <xpang@redhat.com> - 2016-04-18 10:50 +0200
Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Thomas Gleixner <tglx@linutronix.de> - 2016-04-18 11:10 +0200
Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Xunlei Pang <xpang@redhat.com> - 2016-04-18 11:50 +0200
Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Peter Zijlstra <peterz@infradead.org> - 2016-04-20 14:30 +0200
Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Thomas Gleixner <tglx@linutronix.de> - 2016-04-20 14:50 +0200
Re: [PATCH v3 1/6] rtmutex: Deboost before waking up the top waiter Peter Zijlstra <peterz@infradead.org> - 2016-04-20 15:20 +0200
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