From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v5 08/10] xen/arm: Add relinquish_p2m_mapping to remove reference on every mapped page Date: Tue, 17 Dec 2013 14:08:41 +0000 Message-ID: <52B05AE9.8070806@linaro.org> References: <1387215452-10951-1-git-send-email-julien.grall@linaro.org> <1387215452-10951-9-git-send-email-julien.grall@linaro.org> <1387272410.21086.60.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VsvKI-00007q-Cu for xen-devel@lists.xenproject.org; Tue, 17 Dec 2013 14:08:46 +0000 Received: by mail-ea0-f180.google.com with SMTP id f15so2942593eak.39 for ; Tue, 17 Dec 2013 06:08:44 -0800 (PST) In-Reply-To: <1387272410.21086.60.camel@kazak.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, tim@xen.org, Jan Beulich , stefano.stabellini@citrix.com, patches@linaro.org List-Id: xen-devel@lists.xenproject.org On 12/17/2013 09:26 AM, Ian Campbell wrote: > On Mon, 2013-12-16 at 17:37 +0000, Julien Grall wrote: >> + if ( op == RELINQUISH && count == LPAE_ENTRIES && >> + hypercall_preempt_check() ) >> + { > > If hypercall_preempt_check returns false the first time it is called > then you won't ever try again. I think you want > (count+1 % LPAE_ENTRIES) == 0 > (the +1 avoids preempting without having done any work yet) > > (credit to Jan for pointing this out in his review of Mukesh's x86 > variant) The code was copied from relinquish_shared_pages (arch/x86/mem_sharing.c), so if I'm not mistaken this code is also buggy. -- Julien Grall