Re: Is read barrier missed in kfifo?

2018-05-14 Thread Paul E. McKenney
On Mon, May 14, 2018 at 08:57:55AM +0200, Peter Zijlstra wrote: > On Fri, May 11, 2018 at 09:20:53AM -0700, Paul E. McKenney wrote: > > On Fri, May 11, 2018 at 10:32:42AM +0200, Peter Zijlstra wrote: > > > On Fri, May 11, 2018 at 03:25:18PM +0800, Xiao Guangrong wrote: > > > > > > > > Hi, > > > >

Re: Is read barrier missed in kfifo?

2018-05-14 Thread Peter Zijlstra
On Fri, May 11, 2018 at 09:20:53AM -0700, Paul E. McKenney wrote: > On Fri, May 11, 2018 at 10:32:42AM +0200, Peter Zijlstra wrote: > > On Fri, May 11, 2018 at 03:25:18PM +0800, Xiao Guangrong wrote: > > > > > > Hi, > > > > > > Currently, there is no read barrier between reading the index > > > (

Re: Is read barrier missed in kfifo?

2018-05-11 Thread Paul E. McKenney
On Fri, May 11, 2018 at 10:32:42AM +0200, Peter Zijlstra wrote: > On Fri, May 11, 2018 at 03:25:18PM +0800, Xiao Guangrong wrote: > > > > Hi, > > > > Currently, there is no read barrier between reading the index > > (kfifo.in) and fetching the real data from the fifo. > > > > I am afraid that wi

Re: Is read barrier missed in kfifo?

2018-05-11 Thread Peter Zijlstra
On Fri, May 11, 2018 at 03:25:18PM +0800, Xiao Guangrong wrote: > > Hi, > > Currently, there is no read barrier between reading the index > (kfifo.in) and fetching the real data from the fifo. > > I am afraid that will cause the vfifo is observed as not empty > however the data is not actually r

Re: Is read barrier missed in kfifo?

2018-05-11 Thread Stefani Seibold
My guts thinks you are right. Feel free to send a patch... Am Freitag, den 11.05.2018, 15:25 +0800 schrieb Xiao Guangrong: > Hi, > > Currently, there is no read barrier between reading the index > (kfifo.in) and fetching the real data from the fifo. > > I am afraid that will cause the vfifo is o

Is read barrier missed in kfifo?

2018-05-11 Thread Xiao Guangrong
Hi, Currently, there is no read barrier between reading the index (kfifo.in) and fetching the real data from the fifo. I am afraid that will cause the vfifo is observed as not empty however the data is not actually ready for read. Right? Thanks!