Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752644AbbBXP6f (ORCPT ); Tue, 24 Feb 2015 10:58:35 -0500 Received: from mail.bmw-carit.de ([62.245.222.98]:36390 "EHLO mail.bmw-carit.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752426AbbBXP6c (ORCPT ); Tue, 24 Feb 2015 10:58:32 -0500 Message-ID: <54EC9FA2.1030000@bmw-carit.de> Date: Tue, 24 Feb 2015 16:58:26 +0100 From: Daniel Wagner User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Andi Kleen CC: Jeff Layton , , , John Kacur , Alexander Viro , "J. Bruce Fields" Subject: Re: [RFC v1 0/5] fs/locks: Use plain percpu spinlocks instead of lglock to protect file_lock References: <1424443195-18676-1-git-send-email-daniel.wagner@bmw-carit.de> <87vbiwwotb.fsf@tassilo.jf.intel.com> In-Reply-To: <87vbiwwotb.fsf@tassilo.jf.intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 914 Lines: 21 On 02/20/2015 05:05 PM, Andi Kleen wrote: > Daniel Wagner writes: >> >> I am looking at how to get rid of lglock. Reason being -rt is not too >> happy with that lock, especially that it uses arch_spinlock_t and > > AFAIK it could just use normal spinlock. Have you tried that? I have tried it. At least fs/locks.c didn't blow up. The benchmark results (lockperf) indicated that using normal spinlocks is even slightly faster. Simply converting felt like cheating. It might be necessary for the other user (kernel/stop_machine.c). Currently it looks like there is some additional benefit getting lglock away in fs/locks.c. cheers, daniel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/