From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>, Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-ia64 <linux-ia64@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus
Date: Thu, 24 Sep 2009 07:03:00 +0900 [thread overview]
Message-ID: <4ABA9B14.20904@kernel.org> (raw)
In-Reply-To: <alpine.DEB.1.10.0909231315310.4025@V090114053VZO-1>
Christoph Lameter wrote:
> On Wed, 23 Sep 2009, Tejun Heo wrote:
>
>> any special handling. What problems are you seeing?
>
> per cpu variable access on IA64 does not use the percpu_offset for the
> calculation of the current per cpu data area. Its using a virtual mapping.
>
> How does the new percpu allocator support this? Does it use different
> methods of access for static and dynamic percpu access?
That's only when __ia64_per_cpu_var() macro is used in arch code which
always references static perpcu variable in the kernel image which
falls inside PERCPU_PAGE_SIZE. For everything else, __my_cpu_offset
is defined as __ia64_per_cpu_var(local_per_cpu_offset) and regular
pointer offsetting is used.
Thanks.
--
tejun
next prev parent reply other threads:[~2009-09-23 22:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-22 7:40 [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one Tejun Heo
2009-09-22 7:40 ` [PATCH 1/4] vmalloc: rename local variables vmalloc_start and vmalloc_end Tejun Heo
2009-09-22 22:52 ` Christoph Lameter
2009-09-23 2:08 ` Tejun Heo
2009-09-22 7:40 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo
2009-09-22 22:59 ` Christoph Lameter
2009-09-23 2:11 ` Tejun Heo
2009-09-23 13:44 ` Christoph Lameter
2009-09-23 14:01 ` Tejun Heo
2009-09-23 17:17 ` Christoph Lameter
2009-09-23 22:03 ` Tejun Heo [this message]
2009-09-24 7:36 ` Christoph Lameter
2009-09-24 8:37 ` Tejun Heo
2009-09-28 15:12 ` Christoph Lameter
2009-09-22 7:40 ` [PATCH 3/4] ia64: convert to dynamic percpu allocator Tejun Heo
2009-09-22 7:40 ` [PATCH 4/4] percpu: kill legacy " Tejun Heo
2009-09-22 8:16 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one Ingo Molnar
2009-09-22 20:49 ` Luck, Tony
2009-09-22 21:10 ` Luck, Tony
2009-09-22 21:24 ` Luck, Tony
2009-09-22 21:50 ` Tejun Heo
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