Re: temporarily system freeze with high I/O write to ext2 fs

[Andrew Morton]

James Stevenson wrote:
> 
> > > why is it that Linux 'hangs' while doing heavy I/O operations (such as
> dd)
> > > to (and perhaps from?) ext2 file systems? I can't see the same behaivour
> > > when using other file systems, such as ReiserFS
> > >
> >
> > A partial fix for this went into 2.4.17-pre2.  What kernel are you
> > using?
> 
> i have always had with problem normally during disk writes.
> currently on 2.4.x-14 + 2.4.16

Please try 2.4.17-pre2 or later.

> > For how long does it "hang"?   What exactly are you doing when it
> > occurs?
> 
> its not that it hangs but it gets extremely laggy eg 2/3 seconds pause
> for keyboard input to appear on a console.

Your app got paged out, and the enormous read latencies in 2.4.16
caused it to remain there.