From: Rusty Russell <rusty@rustcorp.com.au>
To: Ravikiran G Thirumalai <kiran@in.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] per-cpu areas
Date: Wed, 13 Feb 2002 20:48:53 +1100 [thread overview]
Message-ID: <E16aw22-0005wa-00@wagner.rustcorp.com.au> (raw)
In-Reply-To: Your message of "Tue, 12 Feb 2002 10:28:52 +0530." <20020212102852.I32236@in.ibm.com>
In message <20020212102852.I32236@in.ibm.com> you write:
> > +static void __init setup_per_cpu_areas(void)
> > +{
> > + unsigned long size, i;
> > + char *ptr;
> > + /* Created by linker magic */
> > + extern char __per_cpu_start[], __per_cpu_end[];
> > +
> > + /* Copy section for each CPU (we discard the original) */
> > + size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
> > + ptr = alloc_bootmem(size * NR_CPUS);
>
> Would it be possible to free up NR_CPUS - smp_num_cpus worth of memory
> after smp_init? ....
Yes, but memory is cheap, and writing a special "partial free"
function for this is icky. Maybe in 2 years when the per-cpu area is
100MB. 8)
We're better off reducing NR_CPUs to the maxmimum possible value of
smp_num_cpus() on that machine, IMHO.
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
next prev parent reply other threads:[~2002-02-13 9:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <E17wsrr-0007bD-00@wagner.rustcorp.com.au>
2002-02-12 4:58 ` Ravikiran G Thirumalai
2002-02-13 9:48 ` Rusty Russell [this message]
2002-02-19 2:05 ` Something Wrong with LKML ???? Zoran Davidovac
2002-02-19 8:19 ` Matti Aarnio
2002-03-05 7:54 [PATCH] per-cpu areas Rusty Russell
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