From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH] input: allocate event circular buffer separately Date: Wed, 16 May 2012 12:40:19 -0700 Message-ID: <20120516194018.GB15920@core.coreip.homeip.net> References: <1337085984-5811-1-git-send-email-mika.kuoppala@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:59456 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756036Ab2EPTk2 (ORCPT ); Wed, 16 May 2012 15:40:28 -0400 Received: by dady13 with SMTP id y13so1409891dad.19 for ; Wed, 16 May 2012 12:40:27 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1337085984-5811-1-git-send-email-mika.kuoppala@nokia.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Mika Kuoppala Cc: linux-input@vger.kernel.org, rydberg@euromail.se Hi Mika, On Tue, May 15, 2012 at 03:46:24PM +0300, Mika Kuoppala wrote: > If struct evdev_client is added to the already power of two > buffer allocation and the buffer is large, for multitouch devices, > the allocation will spill over into the the next page. > Alloc buffer separately instead of binding it to evdev_client struct > to avoid multipage kmalloc. Not counting the event buffer, size of evdev_client is fairly small (under 100 bytes?) so I wonder how often this split actually helps (i.e. buffer and client each are less than page size but combined are more). Thanks. -- Dmitry