From: Christoph Lameter <cl@linux-foundation.org> To: Tejun Heo <tj@kernel.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: Tue, 22 Sep 2009 18:59:26 -0400 (EDT) [thread overview] Message-ID: <alpine.DEB.1.10.0909221856050.9410@V090114053VZO-1> (raw) In-Reply-To: <1253605214-23210-3-git-send-email-tj@kernel.org> On Tue, 22 Sep 2009, Tejun Heo wrote: > > +#ifdef CONFIG_SMP > + . = ALIGN(PERCPU_PAGE_SIZE); > + __cpu0_per_cpu = .; __per_cpu_start? > + . = . + PERCPU_PAGE_SIZE; /* cpu0 per-cpu space */ > +#endif This is a statically sized per cpu area that is used by __get_cpu_var() Data is access via a cpu specific memory mapping. How does this work when the area grows beyond PERCPU_PAGE_SIZE? As far as I can see: It seems that __get_cpu_var would then cause a memory fault?
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Lameter <cl@linux-foundation.org> To: Tejun Heo <tj@kernel.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 Date: Tue, 22 Sep 2009 22:59:26 +0000 [thread overview] Message-ID: <alpine.DEB.1.10.0909221856050.9410@V090114053VZO-1> (raw) In-Reply-To: <1253605214-23210-3-git-send-email-tj@kernel.org> On Tue, 22 Sep 2009, Tejun Heo wrote: > > +#ifdef CONFIG_SMP > + . = ALIGN(PERCPU_PAGE_SIZE); > + __cpu0_per_cpu = .; __per_cpu_start? > + . = . + PERCPU_PAGE_SIZE; /* cpu0 per-cpu space */ > +#endif This is a statically sized per cpu area that is used by __get_cpu_var() Data is access via a cpu specific memory mapping. How does this work when the area grows beyond PERCPU_PAGE_SIZE? As far as I can see: It seems that __get_cpu_var would then cause a memory fault?
next prev parent reply other threads:[~2009-09-22 23:18 UTC|newest] Thread overview: 72+ 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 ` Tejun Heo 2009-09-22 7:40 ` [PATCH 1/4] vmalloc: rename local variables vmalloc_start and vmalloc_end Tejun Heo 2009-09-22 7:40 ` Tejun Heo 2009-09-22 22:52 ` Christoph Lameter 2009-09-22 22:52 ` [PATCH 1/4] vmalloc: rename local variables vmalloc_start and Christoph Lameter 2009-09-23 2:08 ` [PATCH 1/4] vmalloc: rename local variables vmalloc_start and vmalloc_end Tejun Heo 2009-09-23 2:08 ` [PATCH 1/4] vmalloc: rename local variables vmalloc_start and 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 7:40 ` Tejun Heo 2009-09-22 22:59 ` Christoph Lameter [this message] 2009-09-22 22:59 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu Christoph Lameter 2009-09-23 2:11 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo 2009-09-23 2:11 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas Tejun Heo 2009-09-23 13:44 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Christoph Lameter 2009-09-23 13:44 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu Christoph Lameter 2009-09-23 14:01 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo 2009-09-23 14:01 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas Tejun Heo 2009-09-23 17:17 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Christoph Lameter 2009-09-23 17:17 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu Christoph Lameter 2009-09-23 22:03 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo 2009-09-23 22:03 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas Tejun Heo 2009-09-24 7:36 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Christoph Lameter 2009-09-24 7:36 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu Christoph Lameter 2009-09-24 8:37 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo 2009-09-24 8:37 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas Tejun Heo 2009-09-28 15:12 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Christoph Lameter 2009-09-28 15:12 ` [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpu Christoph Lameter 2009-09-22 7:40 ` [PATCH 3/4] ia64: convert to dynamic percpu allocator Tejun Heo 2009-09-22 7:40 ` Tejun Heo 2009-09-22 7:40 ` [PATCH 4/4] percpu: kill legacy " Tejun Heo 2009-09-22 7:40 ` 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 8:16 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic Ingo Molnar 2009-09-22 20:49 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one Luck, Tony 2009-09-22 20:49 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic Luck, Tony 2009-09-22 21:10 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one Luck, Tony 2009-09-22 21:10 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic Luck, Tony 2009-09-22 21:24 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one Luck, Tony 2009-09-22 21:24 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic Luck, Tony 2009-09-22 21:50 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one Tejun Heo 2009-09-22 21:50 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu Tejun Heo 2009-09-23 5:06 [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Tejun Heo 2009-09-23 5:06 ` Tejun Heo 2009-09-23 5:06 ` [PATCH 1/5] ia64: don't alias VMALLOC_END to vmalloc_end Tejun Heo 2009-09-23 5:06 ` Tejun Heo 2009-09-23 5:06 ` [PATCH 2/5] ia64: initialize cpu maps early Tejun Heo 2009-09-23 5:06 ` Tejun Heo 2009-09-23 5:06 ` [PATCH 3/5] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo 2009-09-23 5:06 ` Tejun Heo 2009-09-23 5:06 ` [PATCH 4/5] ia64: convert to dynamic percpu allocator Tejun Heo 2009-09-23 5:06 ` Tejun Heo 2009-09-23 5:06 ` [PATCH 5/5] percpu: kill legacy " Tejun Heo 2009-09-23 5:06 ` Tejun Heo 2009-09-23 11:10 ` Rusty Russell 2009-09-23 11:22 ` Rusty Russell 2009-09-29 0:25 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Tejun Heo 2009-09-29 0:25 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu Tejun Heo 2009-09-30 20:32 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Luck, Tony 2009-09-30 20:32 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic Luck, Tony 2009-09-30 20:47 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Christoph Lameter 2009-09-30 20:47 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu Christoph Lameter 2009-09-30 22:05 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Luck, Tony 2009-09-30 22:05 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic Luck, Tony 2009-09-30 23:06 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Peter Chubb 2009-09-30 23:06 ` Peter Chubb 2009-09-30 23:49 ` Christoph Lameter 2009-09-30 23:49 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu Christoph Lameter 2009-09-30 1:24 ` [PATCH REPOST 3/5] ia64: allocate percpu area for cpu0 like percpu areas for other cpus Tejun Heo 2009-09-30 1:24 ` [PATCH REPOST 3/5] ia64: allocate percpu area for cpu0 like percpu Tejun Heo 2009-10-02 5:11 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu and drop the old one, take#2 Tejun Heo 2009-10-02 5:11 ` [PATCHSET percpu#for-next] percpu: convert ia64 to dynamic percpu Tejun Heo
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