Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail.linuxfoundation.org ([140.211.169.12]:58998 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932647Ab2J2Q2O (ORCPT ); Mon, 29 Oct 2012 12:28:14 -0400 Date: Mon, 29 Oct 2012 09:27:58 -0700 From: Andrew Morton To: Linus Torvalds Cc: Mathieu Desnoyers , Sasha Levin , tj@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, davem@davemloft.net, rostedt@goodmis.org, mingo@elte.hu, ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com, netdev@vger.kernel.org, josh@joshtriplett.org, eric.dumazet@gmail.com, axboe@kernel.dk, agk@redhat.com, dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com, teigland@redhat.com, Trond.Myklebust@netapp.com, bfields@fieldses.org, fweisbec@gmail.com, jesse@nicira.com, venkat.x.venkatsubra@oracle.com, ejt@redhat.com, snitzer@redhat.com, edumazet@google.com, linux-nfs@vger.kernel.org, dev@openvswitch.org, rds-devel@oss.oracle.com, lw@cn.fujitsu.com Subject: Re: [PATCH v7 09/16] SUNRPC/cache: use new hashtable implementation Message-Id: <20121029092758.1ab87d79.akpm@linux-foundation.org> In-Reply-To: References: <1351450948-15618-1-git-send-email-levinsasha928@gmail.com> <1351450948-15618-9-git-send-email-levinsasha928@gmail.com> <20121029124229.GC11733@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 29 Oct 2012 07:49:42 -0700 Linus Torvalds wrote: > Because there's no reason to believe that '9' is in any way a worse > random number than something page-shift-related, is there? 9 is much better than PAGE_SHIFT. PAGE_SIZE can vary by a factor of 16, depending on config. Everyone thinks 4k, and tests only for that. There's potential for very large performance and behavior changes when their code gets run on a 64k PAGE_SIZE machine.