Re: kern/54818: 9.0_RC1 pagedaemon spins

[Andrew Doran <ad%netbsd.org@localhost>]

The following reply was made to PR kern/54818; it has been noted by GNATS.

From: Andrew Doran <ad%netbsd.org@localhost>
To: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>
Cc: gnats-bugs%netbsd.org@localhost, martin%netbsd.org@localhost
Subject: Re: kern/54818: 9.0_RC1 pagedaemon spins
Date: Wed, 15 Jan 2020 14:41:17 +0000

 On Wed, Jan 15, 2020 at 11:32:29PM +0900, Izumi Tsutsui wrote:
 
 > ad@ wrote:
 > 
 > > >  I guess uvm/uvm_pdpolicy_clockpro.c part (empty uvmpdpol_scanfini())
 > > >  isn't necessary, right?
 > > 
 > > It's needed to make it compile, but it does not work on 9.0 or -current.
 > 
 > Ah, I see for options PDPOLICY_CLOCKPRO case.
 > 
 > > Thank you for the vmstat output, that was very helpful.  I think it trying
 > > to balance the queues but your other processes are competing with it, and
 > > because of uvm_pageqlock nobody can make progress.  This is not a problem on
 > > -current any more because uvm_pageqlock is gone..  I have updated the patch
 > > to try and help this situation.  I have not compiled it because I don't have
 > > a 9.0 system at the moment.  Could you please try it again?
 > > 
 > > 	http://www.netbsd.org/~ad/2020/uvm-9.diff 
 > 
 > Thanks, but unfortunately it fails because this change includes
 > "TAILQ_ENTRY(vm_page) pdqueue" not available in netbsd-9:
 
 Oops.  Updated patch is here:
 
 	http://www.netbsd.org/~ad/2020/uvm-9.diff
 
 Thank you,
 Andrew