From: Eric Sandeen Subject: Re: problem(?) in ext4 or mke2fs Date: Sun, 03 Apr 2011 12:21:26 -0700 Message-ID: <4D98C8B6.7050806@redhat.com> References: <4D98BF34.6040503@redhat.com> <4D98C2E0.3010808@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Zeev Tarantov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55663 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752748Ab1DCTVO (ORCPT ); Sun, 3 Apr 2011 15:21:14 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 4/3/11 12:01 PM, Zeev Tarantov wrote: > On Sun, Apr 3, 2011 at 21:56, Eric Sandeen wrote: >> On 4/3/11 11:52 AM, Zeev Tarantov wrote: >>> If the filesystem created with the default options is slow or has >>> higher cpu usage, it should be changed. >> >> I agree. For actual striped storage, this makes it faster, but this >> case is a problem; block-sized stripe width is never going to be good. >> What device is this, exactly? > > Look in linux-2.6/drivers/staging/zram/zram.txt OK, so it does: /* * To ensure that we always get PAGE_SIZE aligned * and n*PAGE_SIZED sized I/O requests. */ blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE); blk_queue_logical_block_size(zram->disk->queue, ZRAM_LOGICAL_BLOCK_SIZE); blk_queue_io_min(zram->disk->queue, PAGE_SIZE); blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); These are all documented in Documentation/ABI/testing/sysfs-block. I don't think that setting all those values in zram is necessary and/or sufficient to achieve what is desired in the comment. io_min/io_opt generally are set only for striped devices. Still, mke2fsprogs should probably sanity-check for this; I'll make sure this seems right, and send a patch. Thanks, -Eric >> -Eric (losing my free airport wifi in about 8 minutes, so I may have >> to continue this later...!) >> >>>> -Eric >>> >>> -Z.T. >>