From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ravikiran G Thirumalai Subject: Re: [patch 9/11] net: dst_entry.refcount, use, lastuse to use alloc_percpu Date: Tue, 13 Sep 2005 16:17:17 -0700 Message-ID: <20050913231717.GC6249@localhost.localdomain> References: <20050913161708.GK3570@localhost.localdomain> <20050913.132442.53540386.davem@davemloft.net> <20050913220737.GA6249@localhost.localdomain> <20050913.151216.48124942.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, dipankar@in.ibm.com, bharata@in.ibm.com, shai@scalex86.org, rusty@rustcorp.com.au, netdev@vger.kernel.org Return-path: To: "David S. Miller" Content-Disposition: inline In-Reply-To: <20050913.151216.48124942.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Sep 13, 2005 at 03:12:16PM -0700, David S. Miller wrote: > From: Ravikiran G Thirumalai > Date: Tue, 13 Sep 2005 15:07:37 -0700 > ... > But using bigrefs, no way. We have enough trouble making the data > structures small without adding bloat like that. A busy server can > have hundreds of thousands of dst cache entries active on it, and they > chew up enough memory as is. > But even 1 Million dst cache entries would be 16+4 MB additional for a 4 cpu box....is that too much? The alloc_percpu reimplementation interleaves objects on cache lines, unlike the existing implementation which pads per-cpu objects to cache lines... If you are referring to embedded routing devices, would they use CONFIG_NUMA or CONFIG_SMP?? (bigrefs nicely fold back to regular atomic_t s on UPs) Thanks, Kiran