linux-kernel - Re: [PATCH v3 12/20] xen/balloon: Don't rely on the page granularity is the same for Xen and Linux

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Message-ID: <55C8A8CA.7070409@citrix.com>
Date:	Mon, 10 Aug 2015 14:36:10 +0100
From:	Julien Grall <julien.grall@...rix.com>
To:	Stefano Stabellini <stefano.stabellini@...citrix.com>
CC:	Wei Liu <wei.liu2@...rix.com>, <ian.campbell@...rix.com>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
	<linux-kernel@...r.kernel.org>,
	David Vrabel <david.vrabel@...rix.com>,
	<xen-devel@...ts.xenproject.org>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3 12/20] xen/balloon: Don't rely on the page granularity
 is the same for Xen and Linux

On 10/08/15 13:55, Stefano Stabellini wrote:
>> If your only concern is the size of the array, we could decrease the
>> number of frames by batch. Or allocation the variable once a boot time.
> 
> Yes, that is my only concern. Allocating only nr_pages new struct page*
> would be good enough I guess.

That would be even worst. We shouldn't allocate the array at every call,
but at boot time.

Note that frame_list is already a static variable use 64KB when 64KB
page is used. I guess this will be unlikely to remove that much frame in
a single batch. But I will keep this optimization for later.

Anyway, I'm wondering if we could re-use the lru field to link the page
when allocate them and retrieve in the second loop in order to avoid the
pages array.

Regards,

-- 
Julien Grall
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