Re: x86: 4kstacks default

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From: Arjan van de Ven
Date: Saturday, April 19, 2008 - 11:00 am

On Sat, 19 Apr 2008 09:59:48 -0500
Shawn Bohrer <shawn.bohrer@gmail.com> wrote:


centos, oracle and redflag tend to follow the RHEL/fedora settings.

To be honest, at this point we're at a situation where
* Several very popular distributions have this enabled for 5+ years,
  apparently without any real issues (otherwise the enterprise releases
  would have turned this off)
* The early "hot known issues" have been resolved afaik, things like
  block device stacking, and symlink recursion lookups are either no longer
  recursive, or a lot less recursive than they used to be.

There are clear benefits to 4K stacks (no need to reiterate the flamewar,
but worth mentioning)
* Less memory consumption in the lowmem zone (critical for enterprise use,
  also good for general performance)
* Kernel stacks at 8K are one of the most prominent order-1 allocations in the
  kernel; again with big-memory systems the fragmentation of the lowmem zone
  is a problem (and the distros that ship 4K stacks went there because of customer
  complaints)

On the flipside the arguments tend to be
1) certain stackings of components still runs the risk of overflowing
2) I want to run ndiswrapper
3) general, unspecified uneasyness.

For 1), we need to know which they are, and then solve them, because even on x86-64 with 8k stacks
they can be a problem (just because the stack frames are bigger, although not quite double, there).
I've not seen any recent reports, I'll try to extend the kerneloops.org client to collect the
"stack is getting low" warning to be able to see how much this really happens.

for 2), the real answer there is "ndiswrapper needs 12kb not 8kb"

for 3), this is hard to deal with but also generally unfounded... you can use this argument against any change in the kernel.

--
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Messages in current thread:
Re: x86: 4kstacks default, Andrew Morton, (Fri Apr 18, 2:29 pm)
Re: x86: 4kstacks default, Ingo Molnar, (Sat Apr 19, 7:23 am)
Re: x86: 4kstacks default, Oliver Pinter, (Sat Apr 19, 7:35 am)
Re: x86: 4kstacks default, Shawn Bohrer, (Sat Apr 19, 7:59 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sat Apr 19, 8:19 am)
Re: x86: 4kstacks default, Oliver Pinter, (Sat Apr 19, 8:42 am)
Re: x86: 4kstacks default, Andrew Morton, (Sat Apr 19, 10:49 am)
Re: x86: 4kstacks default, Arjan van de Ven, (Sat Apr 19, 11:00 am)
Re: x86: 4kstacks default, Ingo Molnar, (Sat Apr 19, 11:33 am)
Re: x86: 4kstacks default, Stefan Richter, (Sat Apr 19, 12:10 pm)
Re: x86: 4kstacks default, Eric Sandeen, (Sat Apr 19, 6:56 pm)
Re: x86: 4kstacks default, Eric Sandeen, (Sat Apr 19, 7:36 pm)
Re: x86: 4kstacks default, Eric Sandeen, (Sat Apr 19, 8:29 pm)
Re: x86: 4kstacks default, Arjan van de Ven, (Sat Apr 19, 11:11 pm)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 12:42 am)
Re: x86: 4kstacks default, Alan Cox, (Sun Apr 20, 1:06 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 1:09 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 1:51 am)
Re: x86: 4kstacks default, Alan Cox, (Sun Apr 20, 2:36 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 3:44 am)
Re: x86: 4kstacks default, Alan Cox, (Sun Apr 20, 4:02 am)
Re: x86: 4kstacks default, Alan Cox, (Sun Apr 20, 4:37 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 4:54 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 5:18 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 5:27 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 5:32 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 5:36 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 5:37 am)
Re: x86: 4kstacks default, Willy Tarreau, (Sun Apr 20, 5:47 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 6:06 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 6:21 am)
Re: x86: 4kstacks default, Mark Lord, (Sun Apr 20, 6:22 am)
Re: x86: 4kstacks default, Mark Lord, (Sun Apr 20, 6:27 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 6:30 am)
Re: x86: 4kstacks default, Willy Tarreau, (Sun Apr 20, 6:34 am)
Re: x86: 4kstacks default, Willy Tarreau, (Sun Apr 20, 6:38 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 7:04 am)
Re: x86: 4kstacks default, Eric Sandeen, (Sun Apr 20, 7:05 am)
Re: x86: 4kstacks default, Eric Sandeen, (Sun Apr 20, 7:09 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 7:19 am)
Re: x86: 4kstacks default, Willy Tarreau, (Sun Apr 20, 7:20 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 7:21 am)
Re: x86: 4kstacks default, Eric Sandeen, (Sun Apr 20, 7:40 am)
Re: x86: 4kstacks default, Eric Sandeen, (Sun Apr 20, 7:56 am)
Re: x86: 4kstacks default, Arjan van de Ven, (Sun Apr 20, 8:41 am)
Re: x86: 4kstacks default, Daniel Hazelton, (Sun Apr 20, 8:44 am)
Re: x86: 4kstacks default, Adrian Bunk, (Sun Apr 20, 9:03 am)
Re: x86: 4kstacks default, Jörn, (Sun Apr 20, 9:41 am)
Re: x86: 4kstacks default, Chris Wedgwood, (Sun Apr 20, 9:59 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 10:19 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 10:26 am)
Re: x86: 4kstacks default, Jörn, (Sun Apr 20, 10:43 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 11:19 am)
Re: x86: 4kstacks default, Arjan van de Ven, (Sun Apr 20, 11:48 am)
Re: x86: 4kstacks default, Arjan van de Ven, (Sun Apr 20, 11:50 am)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 1:01 pm)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 1:09 pm)
Re: x86: 4kstacks default, Jörn, (Sun Apr 20, 1:32 pm)
Re: x86: 4kstacks default, Jörn, (Sun Apr 20, 1:35 pm)
Re: x86: 4kstacks default, Daniel Hazelton, (Sun Apr 20, 1:43 pm)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 2:40 pm)
Re: x86: 4kstacks default, Andrew Morton, (Sun Apr 20, 2:45 pm)
Re: x86: 4kstacks default, Andrew Morton, (Sun Apr 20, 2:50 pm)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 2:51 pm)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 2:55 pm)
Re: x86: 4kstacks default, Bernd Eckenfels, (Sun Apr 20, 3:17 pm)
Re: x86: 4kstacks default, Arjan van de Ven, (Sun Apr 20, 3:33 pm)
Re: x86: 4kstacks default, Arjan van de Ven, (Sun Apr 20, 3:33 pm)
Re: x86: 4kstacks default, David Chinner, (Sun Apr 20, 3:53 pm)
Re: x86: 4kstacks default, Andi Kleen, (Sun Apr 20, 4:16 pm)
Re: x86: 4kstacks default, Avi Kivity, (Sun Apr 20, 4:48 pm)
Re: x86: 4kstacks default, Daniel Hazelton, (Sun Apr 20, 6:45 pm)
Re: x86: 4kstacks default, Eric Sandeen, (Sun Apr 20, 8:06 pm)
Re: x86: 4kstacks default, Alexander E. Patrakov, (Sun Apr 20, 8:30 pm)
Re: x86: 4kstacks default, Arjan van de Ven, (Sun Apr 20, 10:53 pm)
Re: x86: 4kstacks default, Denys Vlasenko, (Mon Apr 21, 12:45 am)
Re: x86: 4kstacks default, Andi Kleen, (Mon Apr 21, 12:51 am)
Re: x86: 4kstacks default, Andi Kleen, (Mon Apr 21, 2:55 am)
Re: x86: 4kstacks default, Eric Sandeen, (Mon Apr 21, 6:29 am)
Re: x86: 4kstacks default, Ingo Molnar, (Mon Apr 21, 7:29 am)
Re: x86: 4kstacks default, Ingo Molnar, (Mon Apr 21, 7:31 am)
Re: x86: 4kstacks default, Daniel Hazelton, (Mon Apr 21, 10:34 am)
Re: x86: 4kstacks default, Denys Vlasenko, (Mon Apr 21, 12:51 pm)
Re: x86: 4kstacks default, Denys Vlasenko, (Mon Apr 21, 1:28 pm)
Re: x86: 4kstacks default, David Chinner, (Mon Apr 21, 6:28 pm)
[PATCH] xfs: do not pass size into kmem_free, it's unused, Denys Vlasenko, (Mon Apr 21, 7:33 pm)
[PATCH] xfs: do not pass unused params to xfs_flush_pages, Denys Vlasenko, (Mon Apr 21, 8:03 pm)
[PATCH] xfs: remove unused parameter of xfs_qm_dqpurge, Denys Vlasenko, (Tue Apr 22, 2:42 am)
Re: x86: 4kstacks default, Denys Vlasenko, (Tue Apr 22, 5:48 am)
Re: x86: 4kstacks default, Adrian Bunk, (Tue Apr 22, 6:01 am)
[PATCH] xfs: expose no-op xfs_put_perag(), Denys Vlasenko, (Tue Apr 22, 6:46 am)
Re: x86: 4kstacks default, Denys Vlasenko, (Tue Apr 22, 6:51 am)
Re: [PATCH] xfs: expose no-op xfs_put_perag(), Eric Sandeen, (Tue Apr 22, 7:08 am)
Re: [PATCH] xfs: #define out unused parameters , Denys Vlasenko, (Tue Apr 22, 10:50 am)
Re: x86: 4kstacks default, Romano Giannetti, (Tue Apr 22, 11:20 am)
Re: [PATCH] xfs: #define out unused parameters , Denys Vlasenko, (Tue Apr 22, 1:46 pm)
Re: [PATCH] xfs: expose no-op xfs_put_perag(), David Chinner, (Tue Apr 22, 4:16 pm)
Re: x86: 4kstacks default, Denys Vlasenko, (Tue Apr 22, 10:03 pm)
Re: x86: 4kstacks default, Daniel Hazelton, (Tue Apr 22, 10:21 pm)
Re: x86: 4kstacks default, david, (Tue Apr 22, 10:25 pm)
Re: x86: 4kstacks default, Benjamin Herrenschmidt, (Tue Apr 22, 10:27 pm)
Re: x86: 4kstacks default, Daniel Hazelton, (Tue Apr 22, 10:41 pm)
Re: x86: 4kstacks default, Romano Giannetti, (Wed Apr 23, 12:46 am)
Re: [PATCH] xfs: remove unused parameter of xfs_qm_dqpurge, Christoph Hellwig, (Wed Apr 23, 1:18 am)
Re: x86: 4kstacks default, Helge Hafting, (Wed Apr 23, 1:57 am)
Re: x86: 4kstacks default, Helge Hafting, (Wed Apr 23, 2:13 am)
Re: x86: 4kstacks default, Stefan Richter, (Wed Apr 23, 4:24 am)
Re: x86: 4kstacks default, Romano Giannetti, (Wed Apr 23, 5:15 am)
Re: x86: 4kstacks default, Lennart Sorensen, (Wed Apr 23, 8:59 am)
Re: x86: 4kstacks default, David Chinner, (Wed Apr 23, 4:29 pm)
Re: x86: 4kstacks default, David Chinner, (Wed Apr 23, 4:36 pm)
Re: x86: 4kstacks default, Arjan van de Ven, (Wed Apr 23, 5:45 pm)
Re: x86: 4kstacks default, Benjamin Herrenschmidt, (Wed Apr 23, 5:56 pm)
Re: x86: 4kstacks default, Christoph Hellwig, (Thu Apr 24, 2:52 am)
Re: x86: 4kstacks default, Peter Zijlstra, (Thu Apr 24, 5:25 am)
Re: x86: 4kstacks default, Chris Mason, (Thu Apr 24, 8:41 am)
Re: x86: 4kstacks default, Eric Sandeen, (Thu Apr 24, 8:46 am)
Re: x86: 4kstacks default, Alexander van Heukelum, (Thu Apr 24, 11:30 am)
Re: x86: 4kstacks default, Jörn, (Sun Apr 27, 12:27 pm)
Re: x86: 4kstacks default, Denys Vlasenko, (Sun Apr 27, 4:02 pm)
Re: x86: 4kstacks default, Eric Sandeen, (Sun Apr 27, 4:08 pm)
Re: x86: 4kstacks default, Denys Vlasenko, (Sun Apr 27, 5:00 pm)
Re: x86: 4kstacks default, Bill Davidsen, (Mon Apr 28, 10:56 am)
Re: x86: 4kstacks default, Bill Davidsen, (Mon Apr 28, 11:38 am)