Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754143Ab3H3UgH (ORCPT ); Fri, 30 Aug 2013 16:36:07 -0400 Received: from g6t0184.atlanta.hp.com ([15.193.32.61]:6946 "EHLO g6t0184.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751791Ab3H3UgF (ORCPT ); Fri, 30 Aug 2013 16:36:05 -0400 Message-ID: <52210225.60805@hp.com> Date: Fri, 30 Aug 2013 16:35:49 -0400 From: Waiman Long User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: Al Viro CC: Linus Torvalds , Ingo Molnar , Benjamin Herrenschmidt , Jeff Layton , Miklos Szeredi , Ingo Molnar , Thomas Gleixner , linux-fsdevel , Linux Kernel Mailing List , Peter Zijlstra , Steven Rostedt , Andi Kleen , "Chandramouleeswaran, Aswin" , "Norton, Scott J" Subject: Re: [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount References: <52200DAE.2020303@hp.com> <5220E56A.80603@hp.com> <5220F090.5050908@hp.com> <20130830194059.GC13318@ZenIV.linux.org.uk> <5220F811.9060902@hp.com> <20130830202608.GD13318@ZenIV.linux.org.uk> In-Reply-To: <20130830202608.GD13318@ZenIV.linux.org.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1296 Lines: 30 On 08/30/2013 04:26 PM, Al Viro wrote: > On Fri, Aug 30, 2013 at 03:52:49PM -0400, Waiman Long wrote: > >> So it is the mnput_no_expire() function that is doing all the >> lg_global_lock() calls. > Interesting... So you are getting a lot of mntput() with ->mnt_ns being > NULL? I wonder which type it is... Note that anything mounted will > have non-NULL ->mnt_ns until umount and anything obtained via > kern_mount/kern_mount_data will also have a non-NULL ->mnt_ns - until > kern_unmount(). > > Could you try to gather stats of that sort? Normally that path should > be only hit by fput() when we have a lazy-unmounted fs and close an opened > file on it... > > I see one potential stupidity in that area (simple_pin_fs() ought to set > ->mnt_ns, with simple_release_fs() clearing it), but there's not a lot > of fs types that would use the damn thing... The AIM7 test was run on a set of 16 ramdisk formated with ext3 filesystem with the following mount options: barrier=0,async,noatime,nodiratime. Maybe that is a factor. Regards, Longman -- 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/