Re: 2.5.34-mm4

[Andrew Morton]

Axel Siebenwirth wrote:
> 
> Hi Andrew!
> 
> On Fri, 13 Sep 2002, Andrew Morton wrote:
> 
> > url: http://www.zip.com.au/~akpm/linux/patches/2.5/2.5.34/2.5.34-mm4/
> 
> With changing from 2.5.34-mm2 to -mm4 I have experienced some moments of
> quite unresponsive behaviour. For example I am building X which at that
> special moment causes pretty heavy disk load and the system doesn't respond
> at all. I was using X and was not able to switch consoles or move mouse only
> extremely sluggish.

There are large IDE updates in -mm4, and this is consistent with
a disk which isn't doing DMA any more.  Could you (and Con) please
double-check with `hdparm -i' and `hdparm -t' that the disk subsystem
is behaving properly?

Yes, it could well be a VM bug, but I wouldn't want to run round in
confused circles all day ;)  Thanks.

> I have seen that it used more swap that usual.

2.5 is much more swaphappy than 2.4.  I believe that this is actually
correct behaviour for optimum throughput.  But it just happens that
people (me included) hate it.  We don't notice the improved runtimes
for the pagecache-intensive operations but we do notice the time it
takes to get the xterms working again.

We have not yet sat down and worked out what to do about this.
 
>              total       used       free     shared    buffers     cached
> Mem:        191096     159340      31756          0      10568      94100
> -/+ buffers/cache:      54672     136424
> Swap:       289160          0     289160
> 
> This is how it looks like under normal circumstances and when building X I
> had 20M in swap usage which seemed quite a lot to me. Maybe I'm just wrong.
> Unfortunately I was not able to start vmstat, first because I can't start
> vmstat when system is not responding and second it doesn't work anyway
> because of your changes.
> 

Yeah, sorry.  The burden of back-compatibility weighed too heavy and
Rik decided that we just have to fix userspace to follow kernel
changes.  There will be breakage for a while;  updates are at
http://surriel.com/procps/.

Unfortunately, those updates cause odd-but-not-serious things to
happen to Red Hat initscripts.  This happens when you install standard
util-linux as well.  It is due to the initscripts passing in arguments
which the standard tools do not understand.