From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v3 4/9] mm: Scrub memory from idle loop Date: Thu, 4 May 2017 13:09:08 -0400 Message-ID: <08bc0925-a8b5-cd45-76e6-19ce0d3678a3@oracle.com> References: <1492184258-3277-1-git-send-email-boris.ostrovsky@oracle.com> <1492184258-3277-5-git-send-email-boris.ostrovsky@oracle.com> <590B657D0200007800156E0C@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <590B657D0200007800156E0C@prv-mh.provo.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Jan Beulich Cc: tim@xen.org, sstabellini@kernel.org, wei.liu2@citrix.com, George.Dunlap@eu.citrix.com, andrew.cooper3@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org 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