Re: [RFC v0] Use swait in completion

2016-03-30 Thread Daniel Wagner
On 03/28/2016 08:57 PM, Steven Rostedt wrote: > On Wed, 9 Mar 2016 13:24:23 +0100 > Sebastian Andrzej Siewior wrote: > >> * Josh Cartwright | 2016-03-08 12:26:56 [-0600]: >> >>> Is it really just about latency? Does this deferral not lead to an >>> inversion in the case where the single woken ta

Re: [RFC v0] Use swait in completion

2016-03-28 Thread Steven Rostedt
On Wed, 9 Mar 2016 13:24:23 +0100 Sebastian Andrzej Siewior wrote: > * Josh Cartwright | 2016-03-08 12:26:56 [-0600]: > > >Is it really just about latency? Does this deferral not lead to an > >inversion in the case where the single woken task isn't the highest > >priority waiter on the completi

Re: [RFC v0] Use swait in completion

2016-03-09 Thread Sebastian Andrzej Siewior
* Josh Cartwright | 2016-03-08 12:26:56 [-0600]: >Is it really just about latency? Does this deferral not lead to an >inversion in the case where the single woken task isn't the highest >priority waiter on the completion (and doesn't run due to a >middle-priority thing spinning)? This would be c

Re: [RFC v0] Use swait in completion

2016-03-08 Thread Josh Cartwright
On Tue, Mar 08, 2016 at 06:52:06PM +0100, Sebastian Andrzej Siewior wrote: > * Daniel Wagner | 2016-03-08 16:59:13 [+0100]: > > >Hi, > Hi, > > >As Peter correctly pointed out in [1] a simple conversion from > >wait to swait in completion.c wont work. I played a bit around and > >came up with this

Re: [RFC v0] Use swait in completion

2016-03-08 Thread Daniel Wagner
On 03/08/2016 06:52 PM, Sebastian Andrzej Siewior wrote: > However I don't think if your DEFER flag solution is all that bad. I > have also the block-mq in -RT using swait and they perform wakes with > irqs-off. Not in -RT but mainline. So me might need something to make it > work properly. But if

Re: [RFC v0] Use swait in completion

2016-03-08 Thread Sebastian Andrzej Siewior
* Daniel Wagner | 2016-03-08 16:59:13 [+0100]: >Hi, Hi, >As Peter correctly pointed out in [1] a simple conversion from >wait to swait in completion.c wont work. I played a bit around and >came up with this rather ugly idea. besides all the things I mentioned privatly, here is what I have curren

[RFC v0] Use swait in completion

2016-03-08 Thread Daniel Wagner
From: Daniel Wagner Hi, As Peter correctly pointed out in [1] a simple conversion from wait to swait in completion.c wont work. I played a bit around and came up with this rather ugly idea. So in case complete_all() is called in hard irq context we just wake up one waiter and let that one call