From owner-freebsd-emulation@freebsd.org Fri Jan 11 18:17:29 2019 Return-Path: Delivered-To: freebsd-emulation@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 423111497A44 for ; Fri, 11 Jan 2019 18:17:29 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id D0C5176DFD for ; Fri, 11 Jan 2019 18:17:28 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 94AAE1497A42; Fri, 11 Jan 2019 18:17:28 +0000 (UTC) Delivered-To: emulation@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8355E1497A40 for ; Fri, 11 Jan 2019 18:17:28 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 222F776DF7 for ; Fri, 11 Jan 2019 18:17:28 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 6A374E10E for ; Fri, 11 Jan 2019 18:17:27 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id x0BIHRVg076005 for ; Fri, 11 Jan 2019 18:17:27 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x0BIHR2q075994 for emulation@FreeBSD.org; Fri, 11 Jan 2019 18:17:27 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: emulation@FreeBSD.org Subject: [Bug 230160] linuxulator doesn't implement madvise(MADV_DONTNEED) and any MADV_ flags with values >= 8 correctly Date: Fri, 11 Jan 2019 18:17:27 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: theraven@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: emulation@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Jan 2019 18:17:29 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D230160 --- Comment #8 from David Chisnall --- (In reply to Bill Sorenson from comment #7) As I said above, there is no mechanism for doing this with shared memory segments - we cannot zero pages in the middle of a shared-memory segment without using memset / bzero and this does not allow the kernel to decommit= the physical pages. I haven't tested whether MAV_FREE allows the kernel to laz= ily replace the pages with zeroed pages, but for our uses we need to guarantee zeroing. On Linux you can do this with some forms of shared memory using fallocate to punch a hole in the underlying object, though apparently it isn't very reliable. --=20 You are receiving this mail because: You are the assignee for the bug.=