From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cyril Hrubis Subject: Re: [PATCH v2] mmap.2: MAP_FIXED updated documentation Date: Mon, 4 Dec 2017 11:55:49 +0100 Message-ID: <20171204105549.GA31332@rei> References: <20171204021411.4786-1-jhubbard@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20171204021411.4786-1-jhubbard-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: john.hubbard-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: Michael Kerrisk , linux-man , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michael Ellerman , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, LKML , linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jann Horn , Matthew Wilcox , Michal Hocko , John Hubbard List-Id: linux-api@vger.kernel.org Hi! I know that we are not touching the rest of the existing description for MAP_FIXED however the second sentence in the manual page says that "addr must be a multiple of the page size." Which however is misleading as this is not enough on some architectures. Code in the wild seems to (mis)use SHMLBA for aligment purposes but I'm not sure that we should advise something like that in the manpages. So what about something as: "addr must be suitably aligned, for most architectures multiple of page size is sufficient, however some may impose additional restrictions for page mapping addresses." Which should at least hint the reader that this is architecture specific. -- Cyril Hrubis chrubis-AlSwsSmVLrQ@public.gmane.org -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html