From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B20EECE58E for ; Mon, 14 Oct 2019 16:50:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 06F7D20854 for ; Mon, 14 Oct 2019 16:50:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FQuybKoj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 06F7D20854 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A12318E0006; Mon, 14 Oct 2019 12:50:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9C0AA8E0001; Mon, 14 Oct 2019 12:50:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8AE9E8E0006; Mon, 14 Oct 2019 12:50:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0100.hostedemail.com [216.40.44.100]) by kanga.kvack.org (Postfix) with ESMTP id 69E1C8E0001 for ; Mon, 14 Oct 2019 12:50:36 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 1CFD16139 for ; Mon, 14 Oct 2019 16:50:36 +0000 (UTC) X-FDA: 76042978872.22.duck25_799609de30a1a X-HE-Tag: duck25_799609de30a1a X-Filterd-Recvd-Size: 7795 Received: from mail-lf1-f66.google.com (mail-lf1-f66.google.com [209.85.167.66]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Mon, 14 Oct 2019 16:50:35 +0000 (UTC) Received: by mail-lf1-f66.google.com with SMTP id y127so12312942lfc.0 for ; Mon, 14 Oct 2019 09:50:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3Ont6zfWVfu9Yqr30VtYctqxSg8UK9ZCwlPYdgg/uAQ=; b=FQuybKojPZocom20uVo0Uanc+MSmyhB62EI2pVqTQkAudsaPZ9U2CxY3X2TZB+Lpem a0KR4W8JYvXzyCf8xMevoEGzeLSup3vSUy9BSCSG+rN22PXma1L0s0J9kOZ/Ctr8p8Z7 e9Q9AKohBrhcMqzNq+yXzK6dzkLJ4/nMNvfDktalWoCfP8jrGmv8f9fosA32tg8nvXTl Vr8l4s3tjerFYLW61FTz+P7pNVnYRPpaCqlLEqpqm03Ou6mhL3BpoSAG3ODwRPijuofv mw8hKAYhnYPqsnX2gpatFO4zyuT/PgNT2m2ZqxysvAi1AQcUzhixa6juSLvOKtQmZDgz FIYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3Ont6zfWVfu9Yqr30VtYctqxSg8UK9ZCwlPYdgg/uAQ=; b=Q+Le2GrbezUTIqobP+r4tjMAbEsBiKB6ZVTKtOOD5k7ykvOInb3hlev712f7u8Wbv3 ZCaIPhhu0oK0ilPUqrAd3i9WIuWkX0uLJe6Q0XQ/ukJKOq+zDY2Y03AXiP6r0qsqteaw Ylh0NHYj1oTuqkRIc1v8oYdTsQDY9lYvqlUDgJcghYukvb73OWjBjMzP/746qNjWOnsV kdjIUlewRTX6zRJOhVsR1jEECXOcq1Q25P/+tHk8KQz7otZmTzwI7cSO0lye+espTDMq RH2j7fBJbFkl7GTSsdnshIHW4J45KEQcx26XNDw6zMo5qQ8kBFIZBn+x7d55QCC5jK6N vZVA== X-Gm-Message-State: APjAAAVjLKhRW/ZAF3yxmz6FWh2MNnQ8ZLZRwemRZkpLlDouiwKM5p2r d2l0kzc5wB+natBXEU5xukc15innEHTt6HisK98= X-Google-Smtp-Source: APXvYqwBiOwg+Padu6rYv5ncypdoq55qu/9AXamvOKKW45w3P2vHQM3n2GzDqMk/Ru9DdqqJlF15N/fc+Mv7b2RHq9Q= X-Received: by 2002:ac2:4142:: with SMTP id c2mr10663361lfi.47.1571071833850; Mon, 14 Oct 2019 09:50:33 -0700 (PDT) MIME-Version: 1.0 References: <20191010230414.647c29f34665ca26103879c4@gmail.com> <20191014164110.GA58307@google.com> In-Reply-To: <20191014164110.GA58307@google.com> From: Vitaly Wool Date: Mon, 14 Oct 2019 18:50:22 +0200 Message-ID: Subject: Re: [PATCH 0/3] Allow ZRAM to use any zpool-compatible backend To: Minchan Kim Cc: Linux-MM , Andrew Morton , Dan Streetman , Sergey Senozhatsky , LKML , Vlastimil Babka , Shakeel Butt , Henry Burns , "Theodore Ts'o" Content-Type: multipart/alternative; boundary="00000000000092c8ce0594e1aa74" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000010, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --00000000000092c8ce0594e1aa74 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Den m=C3=A5n 14 okt. 2019 18:41Minchan Kim skrev: > On Thu, Oct 10, 2019 at 11:04:14PM +0300, Vitaly Wool wrote: > > The coming patchset is a new take on the old issue: ZRAM can currently > be used only with zsmalloc even though this may not be the optimal > combination for some configurations. The previous (unsuccessful) attempt > dates back to 2015 [1] and is notable for the heated discussions it has > caused. > > > > The patchset in [1] had basically the only goal of enabling ZRAM/zbud > combo which had a very narrow use case. Things have changed substantially > since then, and now, with z3fold used widely as a zswap backend, I, as th= e > z3fold maintainer, am getting requests to re-interate on making it possib= le > to use ZRAM with any zpool-compatible backend, first of all z3fold. > > > > The preliminary results for this work have been delivered at Linux > Plumbers this year [2]. The talk at LPC, though having attracted limited > interest, ended in a consensus to continue the work and pursue the goal o= f > decoupling ZRAM from zsmalloc. > > > > The current patchset has been stress tested on arm64 and x86_64 devices= , > including the Dell laptop I'm writing this message on now, not to mention > several QEmu confugirations. > > > > [1] https://lkml.org/lkml/2015/9/14/356 > > [2] https://linuxplumbersconf.org/event/4/contributions/551/ > > Please describe what's the usecase in real world, what's the benefit > zsmalloc > cannot fulfill by desgin and how it's significant. > I really don't want to make fragmentaion of allocator so we should really > see > how zsmalloc cannot achieve things if you are claiming. > Please tell us how to test it so that we could investigate what's the roo= t > cause. > Fragmentation? What do you mean by that? ~Vitaly > --00000000000092c8ce0594e1aa74 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


Den m=C3=A5n 14 okt. 2019 18:41Minchan Kim <minchan@kernel.org> skrev:
<= blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px= #ccc solid;padding-left:1ex">On Thu, Oct 10, 2019 at 11:04:14PM +0300, Vit= aly Wool wrote:
> The coming patchset is a new take on the old issue: ZRAM can currently= be used only with zsmalloc even though this may not be the optimal combina= tion for some configurations. The previous (unsuccessful) attempt dates bac= k to 2015 [1] and is notable for the heated discussions it has caused.
>
> The patchset in [1] had basically the only goal of enabling ZRAM/zbud = combo which had a very narrow use case. Things have changed substantially s= ince then, and now, with z3fold used widely as a zswap backend, I, as the z= 3fold maintainer, am getting requests to re-interate on making it possible = to use ZRAM with any zpool-compatible backend, first of all z3fold.
>
> The preliminary results for this work have been delivered at Linux Plu= mbers this year [2]. The talk at LPC, though having attracted limited inter= est, ended in a consensus to continue the work and pursue the goal of decou= pling ZRAM from zsmalloc.
>
> The current patchset has been stress tested on arm64 and x86_64 device= s, including the Dell laptop I'm writing this message on now, not to me= ntion several QEmu confugirations.
>
> [1] https://lkml.org/lkml/2015/9/14/356
> [2] https://linuxplumberscon= f.org/event/4/contributions/551/

Please describe what's the usecase in real world, what's the benefi= t zsmalloc
cannot fulfill by desgin and how it's significant.
I really don't want to make fragmentaion of allocator so we should real= ly see
how zsmalloc cannot achieve things if you are claiming.
Please tell us how to test it so that we could investigate what's the r= oot
cause.

Fragmentation? What do you mean by that?

<= /div>
~Vitaly
--00000000000092c8ce0594e1aa74--