Messages in this thread | | | Date | Fri, 9 Feb 2018 04:31:59 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 1/2] srcu: Prevent sdp->srcu_gp_seq_needed_exp counter wrap |
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On Tue, Feb 06, 2018 at 01:44:10PM +0300, Ildar Ismagilov wrote: > The results of rcutorture tests in attachment. I only tested: SRCU-N, > SRCU-P, SRCU-t and SRCU-u configs.
That is a good set for an SRUC change, thank you!
Thanx, Paul
> 2018-02-03 12:16 GMT+03:00 Paul E. McKenney <paulmck@linux.vnet.ibm.com>: > > On Wed, Jan 31, 2018 at 10:39:53PM +0300, Ildar Ismagilov wrote: > >> Signed-off-by: Ildar Ismagilov <devix84@gmail.com> > > > > I did apply this for testing and review, thank you and good eyes! > > > > However, I had to: > > > > 1. hand-edit it to make it work against the rcu/dev > > branch of my -rcu tree: > > git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git > > > > 2. fill out the commit logs. > > > > Please see below for the updated patch, and please let me know if I > > messed something up. > > > > In the future, could you please apply your patches against the rcu/dev > > branch of -rcu and provide more complete commit logs? The commit log > > should describe the problem and how that problem is fixed. > > > > Also, are you able to test these using rcutorture? If not, let's get you > > set up for that, as I am prone to testing backlogs just now. Plus I am > > writing this while 34,000 feet over Western Australia. So it would mean > > fewer delays for you if you could test your own patches. ;-) > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 753abb606ba61012c8838c73e2c888aea20efe13 > > Author: Ildar Ismagilov <devix84@gmail.com> > > Date: Wed Jan 31 22:39:53 2018 +0300 > > > > srcu: Prevent sdp->srcu_gp_seq_needed_exp counter wrap > > > > SRCU checks each srcu_data structure's grace-period number for counter > > wrap four times per cycle by default. This frequency guarantees that > > normal comparisons will detect potential wrap. However, the expedited > > grace-period number is not checked. The consquences are not too horrible > > (a failure to expedite a grace period when requested), but it would be > > good to avoid such things. This commit therefore adds this check to > > the expedited grace-period number. > > > > Signed-off-by: Ildar Ismagilov <devix84@gmail.com> > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > > index 2878387d4189..ad3e1aa5e6ea 100644 > > --- a/kernel/rcu/srcutree.c > > +++ b/kernel/rcu/srcutree.c > > @@ -579,6 +579,9 @@ static void srcu_gp_end(struct srcu_struct *sp) > > if (ULONG_CMP_GE(gpseq, > > sdp->srcu_gp_seq_needed + 100)) > > sdp->srcu_gp_seq_needed = gpseq; > > + if (ULONG_CMP_GE(gpseq, > > + sdp->srcu_gp_seq_needed_exp + 100)) > > + sdp->srcu_gp_seq_needed_exp = gpseq; > > spin_unlock_irqrestore_rcu_node(sdp, flags); > > } > > } > > > > > > -- > Best regards > Ildar
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