Re: RE : RE : [Linux-decnet-user] X and Decnet Freeze

[Steven W. <st...@gw...>]

Hi,

Thats the 2.4 version of the patch I was referring to. The problem is tha=
t
for whatever reason, DECnet, probably in its sendmsg() and/or recvmsg()
routines returns an error which is unexpected by X and hence X breaks.

What really needs doing for 2.5, is that both these two routines and the
code paths need rewriting. This would not just solve this problem, but
probably a bunch of others and certainly it would allow support for
zerocopy at the same time (sendpage()).

It is just possible that there is another problem as well, but I think th=
is
is the most likely and Patrick's patches prove where the problem lies to
a certain extent. If you are looking for a good model of what the routine=
s
should look like, look in linux/net/ipv4/tcp.c at the equivalent tcp rout=
ines
taking into account that we need support for SOCK_SEQPACKET as well as
SOCK_STREAM.

I've been working towards this goal for a while and most of the other rec=
ent
patches in 2.5 have been designed to pave the way for these changes. If y=
ou
want to do 2.5 patches, then I suggest starting at the recvmsg() end sinc=
e
that needs to be changed in order to test a new sendmsg() routine! Breaki=
ng
down the changes into small bits is also a good idea where at all possibl=
e,

Steve.

>=20
> Ok, if i think well, it seems the same freeze problem appear on the 2.5=
. So it is not a good solution for me to increase the 2.4 version to 2.5 =
with all the patchs.
>=20
> At this time i'm in locked state.=20
> Could you tell me the Patrick patch which reduces the number of hangs a=
 lot ?=20
> Is it a patch to add to the last send by Patrick ?
>=20
> **************
> Last Patrick patch:
>=20
> --- net/decnet/af_decnet.c.old  2002-11-04 14:12:26.000000000 -0200
> +++ net/decnet/af_decnet.c      2002-11-04 12:45:24.000000000 -0200
> @@ -1771,7 +1771,7 @@
>                         goto out;
>=20
>                 if (signal_pending(current)) {
> -                       rv =3D -ERESTARTSYS;
> +                       rv =3D -EAGAIN;
>                         goto out;
>                 }
>=20
> @@ -1964,7 +1964,8 @@
>                         goto out;
>=20
>                 if (signal_pending(current)) {
> -                       err =3D -ERESTARTSYS;
> +                       /* VMH - testing X crash - printk("DECnet 6\n")=
; */
> +                       err =3D -EAGAIN;
>                         goto out;
>                 }
> ********************
>=20
> Could you explain to me the problem state and if i can help you to do s=
ome test or anything, i'm ready to do it.
>=20
> Thanks,
> M.Bassir
>=20
>=20
> > -----Message d'origine-----
> > De : Steven Whitehouse [mailto:st...@gw...]=20
> > Envoy=E9 : vendredi 5 septembre 2003 12:07
> > =C0 : BASSIR Mohcine
> > Cc : Patrick Caulfield; DECnet list
> > Objet : Re: RE : [Linux-decnet-user] X and Decnet Freeze
> >=20
> >=20
> > Hi,
> >=20
> > >=20
> > > Hi,
> > >=20
> > > I want to solve my XFree freeze problem. For this i think it was=20
> > > necessary to apply all the kernel patch that was write=20
> > since the the=20
> > > 2.4.18 kernel version. Could any one tell me where i can=20
> > found a list=20
> > > of all the patch since this version ? If it is possible i want to=20
> > > increase the decnet part of the kernel to the same state of=20
> > the 2.5.x=20
> > > version.
> > >=20
> > > Steven,
> > >=20
> > > According to your last answare you tell me to wait about=20
> > the porting=20
> > > kernel. Could you telle me the result ?
> >=20
> > Yes. Sorry its been so long - things have got very busy for=20
> > me recently at work and all the DECnet stuff is really just a=20
> > spare time activity for me at the moment.
> >=20
> > It appears that the 2.5 kernel also suffers from the same=20
> > problems as 2.4 when it comes to XFree freezing as Patrick=20
> > has recently been investigating it. He sent me one patch=20
> > which reduces the number of hangs a lot, but still (as I=20
> > understand) does not cure it entirely.
> >=20
> > There are two places to look for patches to DECnet in 2.5.=20
> > Firstly my patches page http://www.chygwyn.com/~steve/kpatch/=20
> > has most if not all of the ones I've written and=20
> http://linux.bkbits.net:8080/linux-2.5
> can be used to query all patches applied to DECnet, whoever wrote them =
and might be the easier reference for you.
>=20
> By all means feel free to produce patches for DECnet in 2.4 but I suspe=
ct it will be a long job since the two kernels are different enough that =
you won't just be able to copy & paste parts. Also beware that some behav=
iour has changed and that I'd rather not back port anything to 2.4 which =
will change DECnet from the users perspective unless it can be shown to b=
e 100% backwards compatible.
>=20
> When 2.6 proper comes out, I'll probably want to give up maintaining DE=
Cnet in 2.4. I think one stable version and one development version at a =
time are enough and there are times when I think that I'm not really givi=
ng them the attention that they deserve. I'm expecting things at work to =
calm down in a month or two and I hope to do some of the larger tasks I h=
ave on my todo list then,
>=20
> Steve.
>=20