From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugzilla-daemon@bugzilla.kernel.org Subject: [Bug 107301] system hang during ext4 xattr operation Date: Wed, 11 Nov 2015 10:28:17 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: linux-ext4@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.136]:47446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752188AbbKKK2U (ORCPT ); Wed, 11 Nov 2015 05:28:20 -0500 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5576B205BA for ; Wed, 11 Nov 2015 10:28:19 +0000 (UTC) Received: from bugzilla2.web.kernel.org (bugzilla2.web.kernel.org [172.20.200.52]) by mail.kernel.org (Postfix) with ESMTP id A74F0204AF for ; Wed, 11 Nov 2015 10:28:17 +0000 (UTC) In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: https://bugzilla.kernel.org/show_bug.cgi?id=107301 --- Comment #15 from Jan Kara --- So I guess there are two separate issues: 1) mbcache scales poorly - that is worth addressing regardless of whether ceph / lustre really need it or not since as you mention there are cases where mbcache helps and scalability is an issue. 2) some usecases do not benefit from mbache much (or at all) and so we could possibly have a heuristic to disable mbcache altogether. My current feeling is that if mbcache is implemented properly, then the overhead of it is a hash-table insertion / deletion when creating / removing xattr and that should be pretty cheap compared to all the other work we do to create external xattr (although cache line contention could be an issue here to some degree). -- You are receiving this mail because: You are watching the assignee of the bug.