From: Michael Neuling <mikey@neuling.org>
To: michael@ellerman.id.au
Cc: paulus@samba.org, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] powerpc: Make the NR_CPUS max 8192
Date: Mon, 18 May 2009 14:14:04 +1000 [thread overview]
Message-ID: <9686.1242620044@neuling.org> (raw)
In-Reply-To: <1242609873.13757.4.camel@concordia>
> > We can compile and boot with NR_CPUS=3D8192, so make this the max. 1024
> > was an arbitrary decision anyway.
>
> Is 8192 still arbitrary? Or does something break above that?
Yeah, the compile breaks after that with 4K pages.
In drivers/base/node.c we have:
/* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));
which causes:
drivers/base/node.c: In function 'node_read_cpumap':
drivers/base/node.c:31: error: size of array 'type name' is negative
I can compile with 16384 CPUs with 64K pages, but it doesn't boot.
sfr asked for size info for different builds, so I may as well repost
them here:
text data bss dec hex filename
9237767 3225768 4409996 16873531 101783b vmlinux.1024
9247355 4769472 7373708 21390535 14664c7 vmlinux.2048
9267239 7857032 13301132 30425403 1d0413b vmlinux.4096
9302623 14035832 25155980 48494435 2e3f763 vmlinux.8192
9373283 26389360 48865676 84628319 50b535f vmlinux.16384
config was pseries_defconfig but with 64K pages.
Mikey
next prev parent reply other threads:[~2009-05-18 4:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-18 1:13 [PATCH] powerpc: Make the NR_CPUS max 8192 Michael Neuling
2009-05-18 1:24 ` Michael Ellerman
2009-05-18 4:14 ` Michael Neuling [this message]
2009-05-18 6:57 ` Geert Uytterhoeven
2009-05-18 7:01 ` Michael Neuling
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