From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:47230 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752718Ab3FDOyP (ORCPT ); Tue, 4 Jun 2013 10:54:15 -0400 Date: Tue, 4 Jun 2013 10:53:22 -0400 From: "J. Bruce Fields" To: Christoph Hellwig Cc: "Stefan (metze) Metzmacher" , Jeff Layton , viro@zeniv.linux.org.uk, matthew@wil.cx, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, cluster-devel@redhat.com, sage@inktank.com, samba-technical@lists.samba.org, Trond.Myklebust@netapp.com, linux-kernel@vger.kernel.org, linux-afs@lists.infradead.org, dhowells@redhat.com, smfrench@gmail.com, linux-fsdevel@vger.kernel.org, ceph-devel@vger.kernel.org, akpm@linux-foundation.org, swhiteho@redhat.com Subject: Re: [PATCH v1 11/11] locks: give the blocked_hash its own spinlock Message-ID: <20130604145322.GH2109@fieldses.org> References: <1370056054-25449-1-git-send-email-jlayton@redhat.com> <1370056054-25449-12-git-send-email-jlayton@redhat.com> <51ADF789.70906@samba.org> <20130604144640.GA7730@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20130604144640.GA7730@infradead.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Jun 04, 2013 at 07:46:40AM -0700, Christoph Hellwig wrote: > Having RCU for modification mostly workloads never is a good idea, so > I don't think it makes sense to mention it here. > > If you care about the overhead it's worth trying to use per-cpu lists, > though. Yes. The lock and unlock could happen on different CPU's--but I think you can make the rule that the lock stays associated with the list it was first put on, and then it's correct in general and hopefully quick in the common case. --b.