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Date: Wed, 2 Aug 2017 08:54:40 -0500 (CDT)
From: Christopher Lameter <cl@linux.com>
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To: "Huang, Ying" <ying.huang@intel.com>
cc: Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org,
        Tejun Heo <tj@kernel.org>, Joerg Roedel <joro@8bytes.org>,
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        Borislav Petkov <bp@suse.de>, Thomas Gleixner <tglx@linutronix.de>,
        Juergen Gross <jgross@suse.com>, Aaron Lu <aaron.lu@intel.com>
Subject: Re: [PATCH 0/3] IPI: Avoid to use 2 cache lines for one
 call_single_data
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On Wed, 2 Aug 2017, Huang, Ying wrote:

> To allocate cache line size aligned percpu memory dynamically,
> alloc_percpu_aligned() is introduced and used in iova drivers too.

alloc_percpu() already aligns objects as specified when they are declared.

Moreover the function is improperly named since it aligns
to a cacheline(). If you want this then you would use

alloc_percpu_cacheline_aligned()

But then the alignment can already be requested by adding
__cacheline_aligned to the per cpu definition.