From owner-freebsd-bugs@freebsd.org Mon Sep 21 17:25:26 2020 Return-Path: Delivered-To: freebsd-bugs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id EFB393F71EF for ; Mon, 21 Sep 2020 17:25:26 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (unknown [127.0.1.3]) by mx1.freebsd.org (Postfix) with ESMTP id 4BwBCp65hcz4XVh for ; Mon, 21 Sep 2020 17:25:26 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id D151D3F70A2; Mon, 21 Sep 2020 17:25:26 +0000 (UTC) Delivered-To: bugs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D11C53F704E for ; Mon, 21 Sep 2020 17:25:26 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4BwBCp5FfQz4Xjc for ; Mon, 21 Sep 2020 17:25:26 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 97B3C11D21 for ; Mon, 21 Sep 2020 17:25:26 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 08LHPQen087404 for ; Mon, 21 Sep 2020 17:25:26 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 08LHPQcV087403 for bugs@FreeBSD.org; Mon, 21 Sep 2020 17:25:26 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: bugs@FreeBSD.org Subject: [Bug 246886] [sendfile] Nginx + NFS or FUSE causes VM stall Date: Mon, 21 Sep 2020 17:25:26 +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: 12.1-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: asomers@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@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-bugs@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Sep 2020 17:25:27 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D246886 --- Comment #55 from Alan Somers --- (In reply to Gleb Smirnoff from comment #54) It's not likely that aio_read makes a difference, since he is seeing the warning about "use unsafe AIO requests". That warning means that aio_read would've returned EOPNOTSUPP without doing anything. UNLESS there's a bug = in aio(4) very high in the stack, before the safety check, that is leaking a resource. Background: "unsafe" AIO means operations where there is no guarantee that = the operation will ever complete, due to network unreliability (in your case), = or disk unreliability, if you're accessing a disk directly rather than a file system. I've never liked that seat belt, because it blocks so many of AIO's best use cases. You can disable it by setting vfs.aio.enable_unsafe=3D1 in /etc/sysctl.conf. I'm puzzled that disabling aio in NGinx makes a difference. Could you plea= se repeat that experiment? It shouldn't matter, if unsafe AIO is disabled and you're serving from NFS or FUSE. --=20 You are receiving this mail because: You are the assignee for the bug.=