From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751546Ab1FMJnD (ORCPT ); Mon, 13 Jun 2011 05:43:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36147 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716Ab1FMJm6 (ORCPT ); Mon, 13 Jun 2011 05:42:58 -0400 Message-ID: <4DF5DB79.3010004@redhat.com> Date: Mon, 13 Jun 2011 11:42:17 +0200 From: Jerome Marchand User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.4pre) Gecko/20091014 Fedora/3.0-2.8.b4.fc11 Thunderbird/3.0b4 MIME-Version: 1.0 To: Nitin Gupta CC: Greg Kroah-Hartman , Linux Kernel List , Robert Jennings , Jeff Moyer , "Martin K. Petersen" , Jens Axboe Subject: Re: [PATCH 3/4] Staging: zram: allow partial page operations References: <1307712529-9757-1-git-send-email-jmarchan@redhat.com> <1307712529-9757-2-git-send-email-jmarchan@redhat.com> <1307712529-9757-3-git-send-email-jmarchan@redhat.com> <4DF2493F.8040507@vflare.org> In-Reply-To: <4DF2493F.8040507@vflare.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/10/2011 06:41 PM, Nitin Gupta wrote: > On 06/10/2011 06:28 AM, Jerome Marchand wrote: >> Commit 7b19b8d45b216ff3186f066b31937bdbde066f08 (zram: Prevent overflow >> in logical block size) introduced ZRAM_LOGICAL_BLOCK_SIZE constant to >> prevent overflow of logical block size on 64k page kernel. >> However, the current implementation of zram only allow operation on block >> of the same size as a page. That makes theorically legit 4k requests fail >> on 64k page kernel. >> >> This patch makes zram allow operation on partial pages. Basically, it >> means we still do operations on full pages internally, but only copy the >> relevent segments from/to the user memory. >> > > Couldn't we just change struct queue_limits.logical_block_size type to > unsigned int or something so it could hold value of 64K? Then we could > avoid making all these changes to handle partial page requests. > > Thanks, > Nitin I believe logical_block_size is meant to be small. I don't know if it is reasonable to set it to such a big value as 64k. I CCed Jens and Martin to have a more valuable opinion on the matter. Regards, Jerome