From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 62E556B0085 for ; Thu, 7 Oct 2010 13:23:30 -0400 (EDT) Date: Thu, 7 Oct 2010 19:23:18 +0200 From: Gleb Natapov Subject: Re: [PATCH v6 04/12] Add memory slot versioning and use it to provide fast guest write interface Message-ID: <20101007172318.GC2397@redhat.com> References: <1286207794-16120-1-git-send-email-gleb@redhat.com> <1286207794-16120-5-git-send-email-gleb@redhat.com> <20101005165738.GA32750@amt.cnet> <20101006111417.GX11145@redhat.com> <20101006143847.GB31423@amt.cnet> <20101006200836.GC4120@minantech.com> <4CAD9A2D.7020009@redhat.com> <20101007154248.GA30949@amt.cnet> <20101007160340.GD4120@minantech.com> <4CADF365.3080406@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CADF365.3080406@redhat.com> Sender: owner-linux-mm@kvack.org To: Avi Kivity Cc: Gleb Natapov , Marcelo Tosatti , kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de, hpa@zytor.com, riel@redhat.com, cl@linux-foundation.org List-ID: On Thu, Oct 07, 2010 at 06:20:53PM +0200, Avi Kivity wrote: > On 10/07/2010 06:03 PM, Gleb Natapov wrote: > >> > > >> > Isn't SET_USER_MEMORY_REGION so slow that calling it 2^32 times > >> > isn't really feasible? > >> > >> Assuming it takes 1ms, it would take 49 days. > >> > >We may fail ioctl when max value is reached. The question is how much slot > >changes can we expect from real guest during its lifetime. > > > > A normal guest has a 30 Hz timer for reading the vga framebuffer, > multiple slots. Let's assume 100 Hz frequency, that gives 490 days > until things stop working. > And reading vga framebuffer needs slots changes because of dirty map tracking? -- Gleb. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org