From nobody Tue Apr 2 12:40:27 2024 X-Original-To: fs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4V86tF0x58z5GWGP for ; Tue, 2 Apr 2024 12:40:37 +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 "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4V86tD6yM4z4tjH for ; Tue, 2 Apr 2024 12:40:36 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1712061637; a=rsa-sha256; cv=none; b=kMncV1avFV6Xl8XoLPFeofzmW7xOrjAD/M3+oLiMs8Zu2lTQHHSRgWkTremxWca2FDMM4O f9Mx9VKCSbZd+MDuR5DVuMgz3fLDZbcrirUarmndYcr7wLn6SFBQnxvptcLD21wb8/oPTf DhM17hZtBRGFr3w9T7ouECnQBZ+WZd6AaxT4bmjsE56VCaCJ1StjBy9JsHsjaW/UyaLIKG x7+FZat4vpphoJRW/a1vqDLQbwlGuT2hpVg9MslF7IDDYyh2N+/C+OKU6zNGRBdXruvuEG X0US0qB90KOe77uduIXfIvUtZLMbEwr7plk42/qWBHp+JrSNPVLSaa8gGyGUjw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1712061637; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1pchJl1qbEXXZv8+z/gcapLvI1y5D5XoyQFOmPTgfbY=; b=yKYNco/iSbgnm87Njwuia3dcoUlrKxT53CaHr3vnIWZ3uBMhcvRlwoc/YUfNxO+1OtCES5 r62crZhTUsISJ1ixMmiHe0lB+Xs1HUpjDkhQr+E/LTG9YoRJfIRcS0+yQY4UEGmcNxTTaI 5VfKm4zY6DpzmCZ0joqZwVOHzpj802ecTTog9BUloUFi4LaMO/1aX+MT1p38MX4j6idi49 vHCP3C6m0KeRJMfWXf0U0cUCie//AG3+C3gG8WWCroA7CD6xJrsvt3bMhzzLBeKpeSXXbp 97VYlMe4p0Ow14A2hoPXaP6bi+2xPUyynB+wxbPoBQK4oQG5zJCT5EzwHGEp1g== 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 4V86tD6ZGJzqBY for ; Tue, 2 Apr 2024 12:40:36 +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 432CeaZI050348 for ; Tue, 2 Apr 2024 12:40:36 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 432CeaK1050342 for fs@FreeBSD.org; Tue, 2 Apr 2024 12:40:36 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: fs@FreeBSD.org Subject: [Bug 275594] High CPU usage by arc_prune; analysis and fix Date: Tue, 02 Apr 2024 12:40:27 +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: 14.0-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: olce@FreeBSD.org X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: fs@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 List-Id: Filesystems List-Archive: https://lists.freebsd.org/archives/freebsd-fs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-fs@freebsd.org MIME-Version: 1.0 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D275594 --- Comment #101 from Olivier Certner --- Hi Seigo, Sorry, I had other things to look for in the meantime, so did not make much progress up to now. That said, from now on I should be able to work on it = near to full-time. (In reply to Seigo Tanimura from comment #99) That is my first target indeed. Seems fairly simple. (In reply to Seigo Tanimura from comment #100) Great. First of all, let me say I've never personally experienced the bug reported here. I'm using poudriere for big builds from time to time, and with ZFS, = but on machines with plenty of RAM, so that may explain why. Bottom-line is th= at I don't have any reproducer on my own at the moment. Will try to spin up som= e VM with a limited amount of RAM, limit the number of vnodes in the system and = the ARC, and see how that goes. Second, it seems that this problem materializes enough and with enough seve= rity that it is quite urgent to find/commit fixes for it. It might be that some= of the changes proposed here cannot be imported as is because of subtle impact= s or design issues (I'm just saying this generally, this may not apply in the en= d).=20 If it happens to be the case, we'll work on proposing alternatives easier to review/get accepted, and defer the other changes. Longer term, the vnode recycling mechanism will probably be completely re-thinked, but hopefully t= he whole of it shouldn't be a requirement to solve the case at hand. So, please bear a little with me until I get up to speed with all your patc= hes and results, and the reports of testers in this bug and some connected ones. --=20 You are receiving this mail because: You are the assignee for the bug.=