Re: kern/55402: amd64/9.99.68/9.99.68: xen/zfs - kernel: double fault trap, code=0

[Jaromír Doleček <jaromir.dolecek%gmail.com@localhost>]

The following reply was made to PR kern/55402; it has been noted by GNATS.

From: =?UTF-8?B?SmFyb23DrXIgRG9sZcSNZWs=?= <jaromir.dolecek%gmail.com@localhost>
To: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%netbsd.org@localhost>
Cc: 
Subject: Re: kern/55402: amd64/9.99.68/9.99.68: xen/zfs - kernel: double fault
 trap, code=0
Date: Sat, 20 Jun 2020 18:55:28 +0200

 Le sam. 20 juin 2020 =C3=A0 15:45, Frank Kardel <kardel%netbsd.org@localhost> a =C3=
 =A9crit :
 >  Well it goes a bit further but hits the double fault
 >
 >  now with 57 frames (two > 1k) at about the same accumulated stack size.
 >
 >  Some space was saved by the patch, but presumably not enough.
 
 OK, I've updated the patch. My previous change in
 vdev_queue_io_to_issue() did not work, gcc returns the stack on the
 end of the function, not when going out of the block.
 
 New version reduced vdev_queue_io_to_issue() to use only 160 bytes of
 stack instead of 1152, and dsl_scan_visitbp()+ dsl_scan_visitdnode()
 pair now takes 40 less bytes.
 
 Can you check if this is enough to get it through?
 
 http://www.netbsd.org/~jdolecek/zfs_reduce_stack.diff
 
 Jaromir