From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: [PATCH] xen: increase static dmesg buffer to 64K Date: Mon, 18 Jul 2011 10:16:28 +0200 Message-ID: <20110718081628.GA22448@aepfle.de> References: <4E23FD1B020000780004DD02@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <4E23FD1B020000780004DD02@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Mon, Jul 18, Jan Beulich wrote: > >>> On 17.07.11 at 17:43, Olaf Hering wrote: > > # HG changeset patch > > # User Olaf Hering > > # Date 1310917380 -7200 > > # Node ID c6cade90d47f32e19f529930ba9f9acfa69f065f > > # Parent 31dd84463eece20bd01c7aee22b52a0c06c67545 > > xen: increase static dmesg buffer to 64K > > > > On large systems the static dmesg buffer will overflow the 16K buffer, early > > messages are lost. Increase the size to 64K to capture all lines on systems > > without serial console. > > Please don't - on small systems it's a waste, and on even larger > systems it still won't help. If anything, the dynamic allocation may > need to happen earlier. As you probably saw, console_init_postirq() > already sizes the buffer dependent on the number of CPUs in the > system. I think conring_size= should be evaluated very early. Is there a way to allocate a range of mfns very early which can then be used for the dmesg buffer? Olaf