Messages in this thread | | | From | Daniel Hazelton <> | Subject | Re: x86: 4kstacks default | Date | Sun, 20 Apr 2008 16:59:51 -0400 |
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On Sunday 20 April 2008 16:23:45 Bodo Eggert wrote: > Daniel Hazelton <dhazelton@enter.net> wrote: > > On Sunday 20 April 2008 08:27:14 Andi Kleen wrote: > >> Adrian Bunk <bunk@kernel.org> writes: > >> > 6k is known to work, and there aren't many problems known with 4k. > >> > > >> > And from a QA point of view the only way of getting 4k thoroughly > >> > tested > >> > >> But you have to first ask why do you want 4k tested? Does it serve > >> any useful purpose in itself? I don't think so. Or you're saying > >> it's important to support 50k kernel threads on 32bit kernels? > > > > Andi, you're the only one I've seen seriously pounding the "50k threads" > > thing - I don't think anyone is really fooled by the straw-man, so I'd > > suggest you drop it. > > > > The real issue is that you think (and are correct in thinking) that > > people are idiots. Yes, there will be breakages if the default is changed > > to 4k stacks - but if people are running new kernels on boxes that'll hit > > stack use problems (that *AREN'T* related to ndiswrapper) and haven't > > made sure that they've configured the kernel properly, then they deserve > > the outcome. It isn't the job of the Linux Kernel to protect the > > incompetent - nor is it the job of linux kernel developers to do such. > > It's the job of the kernel developers to mark experimental and broken > options, and to put a warning: > > "This will break stacking of drivers, especially if disk manager, xfs, RAID > and nfs are used. Yes, linux is broken by default, but only if you intend > to set up a reliable system, so this will be OK!" > > into the help text, instead of expecting each admin to read lkml.
Note that I've yet to meet a competent admin that creates brand new configurations each time they build a new kernel for a machine. Usually they have a "default configuration" for each machine that gets updated each time a new kernel is built. Usually they don't change working options. And since changing things to 4K stacks default would cause a new option - the "8K stacks" option to show up in a "make oldconfig" run - the admin would see it and, hopefully, check the help text and see that it his system, with a deeply stacked driver system (nfs+xfs+raid, for example) and set the 8K stacks option to "Y".
As I said, it isn't the job of the kernel or kernel developers to protect the incompetent (or the lazy).
DRH
-- Dialup is like pissing through a pipette. Slow and excruciatingly painful.
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