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Date: Tue, 18 Apr 2006 16:42:40 +1000
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: Steven Rostedt <rostedt@goodmis.org>
CC: Ravikiran G Thirumalai <kiran@scalex86.org>,
       Christoph Lameter <clameter@sgi.com>,
       LKML <linux-kernel@vger.kernel.org>, Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>, Andi Kleen <ak@suse.de>,
       Martin Mares <mj@atrey.karlin.mff.cuni.cz>, bjornw@axis.com,
       schwidefsky@de.ibm.com, benedict.gaster@superh.com, lethal@linux-sh.org,
       Chris Zankel <chris@zankel.net>, Marc Gauthier <marc@tensilica.com>,
       Joe Taylor <joe@tensilica.com>,
       David Mosberger-Tang <davidm@hpl.hp.com>, rth@twiddle.net,
       spyro@f2s.com, starvik@axis.com, tony.luck@intel.com,
       linux-ia64@vger.kernel.org, ralf@linux-mips.org,
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       parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org,
       paulus@samba.org, linux390@de.ibm.com, davem@davemloft.net
Subject: Re: [PATCH 00/05] robust per_cpu allocation for modules
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Steven Rostedt wrote:

> Understood, but I'm going to start looking in the way Rusty and Arnd
> suggested with the vmalloc approach. This would allow for saving of
> memory and dynamic allocation of module memory making it more robust. And
> all this without that evil extra indirection!

Remember that this approach could effectively just move the indirection to
the TLB / page tables (well, I say "moves" because large kernel mappings
are effectively free compared with 4K mappings).

So be careful about coding up a large amount of work before unleashing it:
I doubt you'll be able to find a solution that doesn't involve tradeoffs
somewhere (but wohoo if you can).

-- 
SUSE Labs, Novell Inc.
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