Messages in this thread | | | Date | Thu, 1 Oct 2015 11:43:13 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched: fix task and run queue run_delay inconsistencies |
| |
On Thu, Oct 01, 2015 at 08:37:32AM +0200, Peter Zijlstra wrote: > On Wed, Sep 30, 2015 at 08:28:41PM +0000, Meyer, Mike wrote:
> > Yes that will also address the issue. > > > > The reason I approached the way I did was to avoid adding code path to > > the far more common uses of {en,de}queue_task() but I doubt anyone is > > going to notice a difference with the addition of some register > > save/restores and a compare in that path. Overall the code does > > shrink with the alternative which is good. > > In most cases the flags should be compile time constants, and with the > inline we can determine the branch at compile time, avoiding emitting > that branch instruction entirely. > > But let me double check the asm for a few important sites.
It looks like the sites in the wakeup path do indeed not get any additional conditionals.
> > My only comment is I am not sure about the naming of the flag > > ENQUEUE_TEMP which implies (to me) the enqueue is temporary which > > clearly it isn't. Maybe something like DEQUEUE_MOVE/ENQUEUE_MOVE > > would be a bit more descriptive of the use case. > > Yes, I ran out of creative juices, let me attempt a better name once > I've woken up a bit.
How about DEQUEUE_SAVE, ENQUEUE_RESTORE ? Ideally I'd wrap the whole pattern into a helper but C isn't really supportive of pre+post patterns like this.
| |