From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net 0/2] net: revert lib/percpu_counter API for fragmentation mem accounting Date: Sun, 03 Sep 2017 11:01:20 -0700 (PDT) Message-ID: <20170903.110120.230269539906979454.davem@davemloft.net> References: <150425790711.22227.12264977619066874632.stgit@firesoul> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, mkubecek@suse.cz, fw@strlen.de, liujian56@huawei.com To: brouer@redhat.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:56454 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753099AbdICSBV (ORCPT ); Sun, 3 Sep 2017 14:01:21 -0400 In-Reply-To: <150425790711.22227.12264977619066874632.stgit@firesoul> Sender: netdev-owner@vger.kernel.org List-ID: From: Jesper Dangaard Brouer Date: Fri, 01 Sep 2017 11:26:03 +0200 > There is a bug in fragmentation codes use of the percpu_counter API, > that can cause issues on systems with many CPUs, above 24 CPUs. > > After much consideration and different attempts at solving the API > usage. The conclusion is to revert to the simple atomic_t API instead. > > The ratio between batch size and threshold size make it a bad use-case > for the lib/percpu_counter API. As using the correct API calls will > unfortunately cause systems with many CPUs to always execute an > expensive sum across all CPUs. Plus the added complexity is not worth it. Series applied, thanks Jesper.