From owner-svn-src-all@freebsd.org Wed Aug 3 07:11:20 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E4026BABD6A; Wed, 3 Aug 2016 07:11:20 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id B55FD1E57; Wed, 3 Aug 2016 07:11:20 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u737BJqI047715; Wed, 3 Aug 2016 07:11:19 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u737BJMS047714; Wed, 3 Aug 2016 07:11:19 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201608030711.u737BJMS047714@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Wed, 3 Aug 2016 07:11:19 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r303703 - head/sys/vm X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Aug 2016 07:11:21 -0000 Author: kib Date: Wed Aug 3 07:11:19 2016 New Revision: 303703 URL: https://svnweb.freebsd.org/changeset/base/303703 Log: Explain why swapgeom_close_ev() is delegated. Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/vm/swap_pager.c Modified: head/sys/vm/swap_pager.c ============================================================================== --- head/sys/vm/swap_pager.c Wed Aug 3 07:10:09 2016 (r303702) +++ head/sys/vm/swap_pager.c Wed Aug 3 07:11:19 2016 (r303703) @@ -2431,8 +2431,9 @@ swapgeom_acquire(struct g_consumer *cp) } /* - * Remove a reference from the g_consumer. Post a close event if - * all references go away. + * Remove a reference from the g_consumer. Post a close event if all + * references go away, since the function might be called from the + * biodone context. */ static void swapgeom_release(struct g_consumer *cp, struct swdevt *sp) @@ -2555,7 +2556,12 @@ swapgeom_close(struct thread *td, struct cp = sw->sw_id; sw->sw_id = NULL; mtx_unlock(&sw_dev_mtx); - /* XXX: direct call when Giant untangled */ + + /* + * swapgeom_close() may be called from the biodone context, + * where we cannot perform topology changes. Delegate the + * work to the events thread. + */ if (cp != NULL) g_waitfor_event(swapgeom_close_ev, cp, M_WAITOK, NULL); }