From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: About `purify-flag' Date: Wed, 27 Feb 2013 09:11:08 -0500 Message-ID: References: <20130227201817.9d47f2a123753a96ec30a79c@gmail.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1361974277 3610 80.91.229.3 (27 Feb 2013 14:11:17 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 27 Feb 2013 14:11:17 +0000 (UTC) Cc: emacs-devel@gnu.org To: Xue Fuqiao Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Feb 27 15:11:40 2013 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UAhjO-0002Ip-D9 for ged-emacs-devel@m.gmane.org; Wed, 27 Feb 2013 15:11:38 +0100 Original-Received: from localhost ([::1]:48790 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UAhj3-0003fH-Bm for ged-emacs-devel@m.gmane.org; Wed, 27 Feb 2013 09:11:17 -0500 Original-Received: from eggs.gnu.org ([208.118.235.92]:45493) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UAhix-0003f3-4b for emacs-devel@gnu.org; Wed, 27 Feb 2013 09:11:15 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UAhiv-000765-L1 for emacs-devel@gnu.org; Wed, 27 Feb 2013 09:11:10 -0500 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.182]:61080) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UAhiv-000760-Hz for emacs-devel@gnu.org; Wed, 27 Feb 2013 09:11:09 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av4EABK/CFFFxKJt/2dsb2JhbABEvw4Xc4IeAQEEAVYjBQsLDiYSFBgNJIgeBsEtjSWDZQOIYZwZgV6DFYFJ X-IPAS-Result: Av4EABK/CFFFxKJt/2dsb2JhbABEvw4Xc4IeAQEEAVYjBQsLDiYSFBgNJIgeBsEtjSWDZQOIYZwZgV6DFYFJ X-IronPort-AV: E=Sophos;i="4.84,565,1355115600"; d="scan'208";a="2595061" Original-Received: from 69-196-162-109.dsl.teksavvy.com (HELO pastel.home) ([69.196.162.109]) by ironport2-out.teksavvy.com with ESMTP/TLS/ADH-AES256-SHA; 27 Feb 2013 09:11:07 -0500 Original-Received: by pastel.home (Postfix, from userid 20848) id 34C456BCBF; Wed, 27 Feb 2013 09:11:08 -0500 (EST) In-Reply-To: <20130227201817.9d47f2a123753a96ec30a79c@gmail.com> (Xue Fuqiao's message of "Wed, 27 Feb 2013 20:18:17 +0800") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 206.248.154.182 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:157427 Archived-At: > In (info "(elisp) Pure Storage"): > -- Variable: purify-flag > [...] > This flag is `t' while loading all of the basic functions for > building Emacs initially (allowing those functions to be shareable > and non-collectible). > What does "shareable and non-collectible" mean here? Basically, the idea is that the "pure space" will never be written to, so the OS can use the same VM memory pages for the pure space of several Emacs processes. I.e. the "pure space" can be shared among Emacs processes. Non-collectible means that they will never be garbage collected (the GC never even looks at them). Stefan