X-Spam-Check-By: sourceware.org Date: Fri, 5 Jan 2007 11:34:36 -0500 From: Christopher Faylor To: cygwin@cygwin.com Subject: Re: 1.7.0 CVS mmap failure Message-ID: <20070105163436.GA28426@trixie.casa.cgf.cx> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <20070105095752.GB28768@calimero.vinschen.de> <20070105160215.GA5674@ns1.anodized.com> <20070105160650.GJ3521@implementation.labri.fr> <20070105161751.GB5674@ns1.anodized.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070105161751.GB5674@ns1.anodized.com> User-Agent: Mutt/1.5.11 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com On Fri, Jan 05, 2007 at 08:17:51AM -0800, Christopher Layne wrote: >mmap() is supposed to zero-fill, not refuse to map when len >is less than the system page size. I have never ever seen >mmap() fail to map less than page size on any typical Posix >system. > >" > The system shall always zero-fill any partial page at the end > of an object. Further, the system shall never write out any > modified portions of the last page of an object which are > beyond its end. References within the address range starting > at pa and continuing for len bytes to whole pages following the > end of an object shall result in delivery of a SIGBUS signal. >" > >Back to the original issue, consider this: > >MEM_TOP_DOWN >0x100000 Allocates memory at the highest possible address. > >If there were any kind of simple arithmetic bug behind mmap()'s >scenes (such as computing space to zero-fill, etc. etc.) I would >think ENOMEM would be a very common scenario if we're allocating >near the end of addressible space. % grep "simple arithmetic bug" mmap.cc % Seems fine to me. It's probably a hyperthreaded, dual-core problem. cgf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/