Date: Mon, 3 Jan 2005 10:25:18 -0200
From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, linux-kernel@vger.kernel.org,
       Thomas Gleixner <tglx@linutronix.de>, Andrew Morton <akpm@osdl.org>
Subject: Re: VM fixes [2/4]
Message-ID: <20050103122518.GF29158@logos.cnet>
References: <20041224173558.GC13747@dualathlon.random> <41D46F4A.5080505@yahoo.com.au> <20050102163236.GI5164@dualathlon.random>
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On Sun, Jan 02, 2005 at 05:32:36PM +0100, Andrea Arcangeli wrote:
> On Fri, Dec 31, 2004 at 08:12:42AM +1100, Nick Piggin wrote:
> > Andrea Arcangeli wrote:
> > >This is the forward port to 2.6 of the lowmem_reserved algorithm I
> > >invented in 2.4.1*, merged in 2.4.2x already and needed to fix workloads
> > >like google (especially without swap) on x86 with >1G of ram, but it's
> > >needed in all sort of workloads with lots of ram on x86, it's also
> > >needed on x86-64 for dma allocations. This brings 2.6 in sync with
> > >latest 2.4.2x.
> > >
> > 
> > This looks OK to me. It really simplifies the code there a lot too.
> > 
> > The only questions I have are: should it be on by default? I don't think
> > we ever reached an agreement. I'd say yes, after a run in -mm because it
> > does potentially fix corner cases where lower zones get filled with un-
> > freeable memory which could have been satisfied with higher zones.
> 
> Great, thanks for the review! I definitely agree it should be on by
> default, I already had an hang report that was solved by more recent
> kernels and that probably can only be explained by lowmem_reserve since
> there aren't other mm changes in 2.6.5 based trees. 
> 
> > And second, any chance you could you port it to the mm patches already in
> > -mm? Won't be a big job, just some clashes in __alloc_pages...
> 
> I already had to port to 2.6.5 too, and that's enough for now unless I
> first get a positive ack that it will be merged (if I hadn't more
> interesting things to develop, I would be happily porting it).

I believe it can be accepted easily if you change the variable names
from protection to lowmem_reserve.

Is there a need for that or its just your taste? :)
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