2004-01-29 19:28:20

by Tim Hockin

[permalink] [raw]
Subject: PATCH - NGROUPS 2.6.2rc2 + fixups

Linus, Andrew,

Attached is a patch to remove the NGROUPS limit (again). I've fixed up the
issues that people have pointed out this week. It incorporates a fixed
limit which can be easily changed in a user wanted even more groups.

This patch is against linux-2.6.2rc2. If it is OK, I can make it bitkeeper
accessible.

What think?

--
Tim Hockin
Sun Microsystems, Linux Software Engineering
[email protected]
All opinions are my own, not Sun's


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2004-01-29 19:42:37

by Linus Torvalds

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Subject: Re: PATCH - NGROUPS 2.6.2rc2 + fixups



On Thu, 29 Jan 2004, Tim Hockin wrote:
>
> What think?

I still don't understand the complexity.

Why the list of pages? Is there really any valid use for this that could
overflow a simple "kmalloc()"? How many groups do people really really
need?

I just find it wrong to go from 32 to millions. And a few thousand can
trivially be handled by a normal "kmalloc()".

Basically, I find overdesign physically nauseating. This is less so than
the original stuff, but I'm still finding myself asking "Why?".

Linus

2004-01-30 02:17:49

by Rusty Russell

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Subject: Re: PATCH - NGROUPS 2.6.2rc2 + fixups

In message <[email protected]> you write:
>
>
> On Thu, 29 Jan 2004, Tim Hockin wrote:
> >
> > What think?
>
> I still don't understand the complexity.
>
> Why the list of pages? Is there really any valid use for this that could
> overflow a simple "kmalloc()"? How many groups do people really really
> need?

I was happy with kmalloc, and no sorting. Simple patch. Tim
complained that he had some wierd-ass users who hit kmalloc limits w/
fragmentation. I added about 10 lines of code to fall back to vmalloc
for that very rare case, and you scotched that.

ie. Don't blame Tim: you led us here 8(

Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.