Re: Break 2.4 VM in five easy steps

2001-06-07 Thread Derek Glidden
Miles Lane wrote: > > So please, if you have new facts that you want to offer that > will help us characterize and understand these VM issues better > or discover new problems, feel free to share them. But if you > just want to rant, I, for one, would rather you didn't. *sigh* Not to prolong

Re: Break 2.4 VM in five easy steps

2001-06-07 Thread Derek Glidden
Miles Lane wrote: So please, if you have new facts that you want to offer that will help us characterize and understand these VM issues better or discover new problems, feel free to share them. But if you just want to rant, I, for one, would rather you didn't. *sigh* Not to prolong an

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Mike Galbraith wrote: > > Can you try the patch below to see if it helps? If you watch > with vmstat, you should see swap shrinking after your test. > Let is shrink a while and then see how long swapoff takes. > Under a normal load, it'll munch a handfull of them at least > once a second and

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
"Eric W. Biederman" wrote: > > Derek Glidden <[EMAIL PROTECTED]> writes: > > > The problem I reported is not that 2.4 uses huge amounts of swap but > > that trying to recover that swap off of disk under 2.4 can leave the > > machine in an entirely unre

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
"Eric W. Biederman" wrote: > > > Or are you saying that if someone is unhappy with a particular > > situation, they should just keep their mouth shut and accept it? > > It's worth complaining about. It is also worth digging into and find > out what the real problem is. I have a hunch that

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
John Alvord wrote: > > On Wed, 06 Jun 2001 11:31:28 -0400, Derek Glidden > <[EMAIL PROTECTED]> wrote: > > > > >I'm beginning to be amazed at the Linux VM hackers' attitudes regarding > >this problem. I expect this sort of behaviour from academics - ig

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
> Funny. I can count many ways in which 4.3BSD, SunOS{3,4} and post-4.4 BSD > systems I've used were broken, but I've never thought that swap==2*RAM rule > was one of them. Yes, but Linux isn't 4.3BSD, SunOS or post-4.4 BSD. Not to mention, all other OS's I've had experience using *don't*

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Helge Hafting wrote: > > The drive is inactive because it isn't needed, the machine is > running loops on data in memory. And it is unresponsive because > nothing else is scheduled, maybe "swapoff" is easier to implement I don't quite get what you're saying. If the system becomes unresponsive

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Xavier Bestel wrote: > > Did you try to put twice as much swap as you have RAM ? (e.g. add a 512M > swapfile to your box) > This is what Linus recommended for 2.4 (swap = 2 * RAM), saying that > anything less won't do any good: 2.4 overallocates swap even if it > doesn't use it all. So in your

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Bill Pringlemeir wrote: > > [snip] > Derek> overwhelmed. On the system I'm using to write this, with > Derek> 512MB of RAM and 512MB of swap, I run two copies of this > > Please see the following message on the kernel mailing list, > > 3086:Linus 2.4.0 notes are quite clear that you need at

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Bill Pringlemeir wrote: [snip] Derek overwhelmed. On the system I'm using to write this, with Derek 512MB of RAM and 512MB of swap, I run two copies of this Please see the following message on the kernel mailing list, 3086:Linus 2.4.0 notes are quite clear that you need at least

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Xavier Bestel wrote: Did you try to put twice as much swap as you have RAM ? (e.g. add a 512M swapfile to your box) This is what Linus recommended for 2.4 (swap = 2 * RAM), saying that anything less won't do any good: 2.4 overallocates swap even if it doesn't use it all. So in your case

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Helge Hafting wrote: The drive is inactive because it isn't needed, the machine is running loops on data in memory. And it is unresponsive because nothing else is scheduled, maybe swapoff is easier to implement I don't quite get what you're saying. If the system becomes unresponsive

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Funny. I can count many ways in which 4.3BSD, SunOS{3,4} and post-4.4 BSD systems I've used were broken, but I've never thought that swap==2*RAM rule was one of them. Yes, but Linux isn't 4.3BSD, SunOS or post-4.4 BSD. Not to mention, all other OS's I've had experience using *don't* break

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
John Alvord wrote: On Wed, 06 Jun 2001 11:31:28 -0400, Derek Glidden [EMAIL PROTECTED] wrote: I'm beginning to be amazed at the Linux VM hackers' attitudes regarding this problem. I expect this sort of behaviour from academics - ignoring real actual problems being reported by real

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Eric W. Biederman wrote: Or are you saying that if someone is unhappy with a particular situation, they should just keep their mouth shut and accept it? It's worth complaining about. It is also worth digging into and find out what the real problem is. I have a hunch that this hole

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Eric W. Biederman wrote: Derek Glidden [EMAIL PROTECTED] writes: The problem I reported is not that 2.4 uses huge amounts of swap but that trying to recover that swap off of disk under 2.4 can leave the machine in an entirely unresponsive state, while 2.2 handles identical situations

Re: Break 2.4 VM in five easy steps

2001-06-06 Thread Derek Glidden
Mike Galbraith wrote: Can you try the patch below to see if it helps? If you watch with vmstat, you should see swap shrinking after your test. Let is shrink a while and then see how long swapoff takes. Under a normal load, it'll munch a handfull of them at least once a second and keep

Re: Break 2.4 VM in five easy steps

2001-06-05 Thread Derek Glidden
On Wed, Jun 06, 2001 at 12:16:30PM +1000, Andrew Morton wrote: > "Jeffrey W. Baker" wrote: > > > > Because the 2.4 VM is so broken, and > > because my machines are frequently deeply swapped, > > The swapoff algorithms in 2.2 and 2.4 are basically identical. > The problem *appears* worse in 2.4

Break 2.4 VM in five easy steps

2001-06-05 Thread Derek Glidden
After reading the messages to this list for the last couple of weeks and playing around on my machine, I'm convinced that the VM system in 2.4 is still severely broken. This isn't trying to test extreme low-memory pressure, just how the system handles recovering from going somewhat into swap,

Break 2.4 VM in five easy steps

2001-06-05 Thread Derek Glidden
After reading the messages to this list for the last couple of weeks and playing around on my machine, I'm convinced that the VM system in 2.4 is still severely broken. This isn't trying to test extreme low-memory pressure, just how the system handles recovering from going somewhat into swap,

Re: Break 2.4 VM in five easy steps

2001-06-05 Thread Derek Glidden
On Wed, Jun 06, 2001 at 12:16:30PM +1000, Andrew Morton wrote: Jeffrey W. Baker wrote: Because the 2.4 VM is so broken, and because my machines are frequently deeply swapped, The swapoff algorithms in 2.2 and 2.4 are basically identical. The problem *appears* worse in 2.4 because it