From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753340AbeBIXYp (ORCPT ); Fri, 9 Feb 2018 18:24:45 -0500 Received: from mail-lf0-f41.google.com ([209.85.215.41]:41269 "EHLO mail-lf0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753269AbeBIXYn (ORCPT ); Fri, 9 Feb 2018 18:24:43 -0500 X-Google-Smtp-Source: AH8x226V3J/Cw9p7bWTUAxTBwbiOn+7TMreTL88lNZ/YNEyb6GLqPWrosbieYMIbCQwdjkEiVPlXyA== From: Andrew Randrianasulu To: linux-kernel@vger.kernel.org Subject: Zstd and zram - not finished? Date: Sat, 10 Feb 2018 02:13:51 +0300 User-Agent: KMail/1.9.10 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201802100213.52152.randrianasulu@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I was trying to test zstd compression for zram devices with kernel 4.15 But to my surprize I found zstd comressor missing from list of compression algos. I found out this patch or equivalent was still missing in 4.15 and missing in 4.16 as it nearing -rc1: https://lkml.org/lkml/2017/8/4/582 [PATCH v4 5/5] crypto: Add zstd support After manually applying this patch I can see cat /sys/class/block/zram0/comp_algorithm [lzo] lz4 lz4hc 842 zstd and can change algo to zstd If I try and mkfs.ext2 this device (with size, say, ~1Gb) - I can uncompress nearly full kernel tree into it (I first run out of inodes, tons of small files for such small "disk", re-run mkfs with specified number of inodes, around 100 000, worked). But 1Gb device probably was visible size of device, not amount of memory it consumes..So, I run mkfs.btrfs over /dev/zram0 with zstd compression. This give me ~1Gb sized device able to keep full kernel tree, and compile it , too. So, I assume it worked ....