From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755358AbbINOMY (ORCPT ); Mon, 14 Sep 2015 10:12:24 -0400 Received: from mail-qk0-f171.google.com ([209.85.220.171]:36163 "EHLO mail-qk0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753683AbbINOMX (ORCPT ); Mon, 14 Sep 2015 10:12:23 -0400 MIME-Version: 1.0 In-Reply-To: <55F6D356.5000106@suse.cz> References: <20150914154901.92c5b7b24e15f04d8204de18@gmail.com> <55F6D356.5000106@suse.cz> Date: Mon, 14 Sep 2015 16:12:22 +0200 Message-ID: Subject: Re: [PATCH 0/3] allow zram to use zbud as underlying allocator From: Vitaly Wool To: Vlastimil Babka Cc: minchan@kernel.org, sergey.senozhatsky@gmail.com, ddstreet@ieee.org, LKML , linux-mm@kvack.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 14, 2015 at 4:01 PM, Vlastimil Babka wrote: > > On 09/14/2015 03:49 PM, Vitaly Wool wrote: >> >> While using ZRAM on a small RAM footprint devices, together with >> KSM, >> I ran into several occasions when moving pages from compressed swap back >> into the "normal" part of RAM caused significant latencies in system > > > I'm sure Minchan will want to hear the details of that :) > >> operation. By using zbud I lose in compression ratio but gain in >> determinism, lower latencies and lower fragmentation, so in the coming > > > I doubt the "lower fragmentation" part given what I've read about the design of zbud and zsmalloc? As it turns out, I see more cases of compaction kicking in and significantly more compact_stalls with zsmalloc. ~vitaly From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f51.google.com (mail-qg0-f51.google.com [209.85.192.51]) by kanga.kvack.org (Postfix) with ESMTP id 7326F6B0266 for ; Mon, 14 Sep 2015 10:12:23 -0400 (EDT) Received: by qgx61 with SMTP id 61so115691253qgx.3 for ; Mon, 14 Sep 2015 07:12:23 -0700 (PDT) Received: from mail-qk0-x234.google.com (mail-qk0-x234.google.com. [2607:f8b0:400d:c09::234]) by mx.google.com with ESMTPS id c61si12149733qga.112.2015.09.14.07.12.22 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 14 Sep 2015 07:12:22 -0700 (PDT) Received: by qkcf65 with SMTP id f65so58458547qkc.3 for ; Mon, 14 Sep 2015 07:12:22 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <55F6D356.5000106@suse.cz> References: <20150914154901.92c5b7b24e15f04d8204de18@gmail.com> <55F6D356.5000106@suse.cz> Date: Mon, 14 Sep 2015 16:12:22 +0200 Message-ID: Subject: Re: [PATCH 0/3] allow zram to use zbud as underlying allocator From: Vitaly Wool Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: minchan@kernel.org, sergey.senozhatsky@gmail.com, ddstreet@ieee.org, LKML , linux-mm@kvack.org On Mon, Sep 14, 2015 at 4:01 PM, Vlastimil Babka wrote: > > On 09/14/2015 03:49 PM, Vitaly Wool wrote: >> >> While using ZRAM on a small RAM footprint devices, together with >> KSM, >> I ran into several occasions when moving pages from compressed swap back >> into the "normal" part of RAM caused significant latencies in system > > > I'm sure Minchan will want to hear the details of that :) > >> operation. By using zbud I lose in compression ratio but gain in >> determinism, lower latencies and lower fragmentation, so in the coming > > > I doubt the "lower fragmentation" part given what I've read about the design of zbud and zsmalloc? As it turns out, I see more cases of compaction kicking in and significantly more compact_stalls with zsmalloc. ~vitaly -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org