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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8C36C433EF for ; Wed, 27 Apr 2022 22:31:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232128AbiD0WeV (ORCPT ); Wed, 27 Apr 2022 18:34:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229774AbiD0WeR (ORCPT ); Wed, 27 Apr 2022 18:34:17 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B36846B641 for ; Wed, 27 Apr 2022 15:31:04 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id d15so2772531plh.2 for ; Wed, 27 Apr 2022 15:31:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Jf9KoOg1H3jqjBGppZ/xxewMSo8dDOurdWUb3cYmU3c=; b=J86DG36ucbx0DlDChH/QyA2qGW9ZzuTV7lPr4Yhhk3+pV9+Qw+iYZfs23hrlx4+rfD giclbY4+1PxmOyj+mAHsv9VmlcODeRZorL+++DJBAt9RJIWnhq1wlvZL0JvKpHuHICLm dxEKItjNOKe2JxdIPAzsQ5baFAnBGf2Vh3niiGtwf9zwcMz93g13wjD3YEk9QkeLE+YK eFBdwJmwsg7s6P8IKgVpVGlIcKASf75RQGMzBKCQ7cQziovaXYvVEqGxP7AJ5aMa2M26 RzZiEP14nT+f6jEpI0c9BCalzL328U8Fwv1zPeSnLj5NaVl3egPq1TcLnDuB8YzNCPxq C43g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Jf9KoOg1H3jqjBGppZ/xxewMSo8dDOurdWUb3cYmU3c=; b=MkfbtjqZyE+gJRijcvPf3O1aQS5vLNI8BNDJB3KabMqtIkv6Xokdio+2KsJoCu9Z7p S6p4bjWUnF3AzRrGdszXzi0oJBFxjAR/1HYtd/0nFd7iCexXXhGIc03kiOq3GPnYdqjI aJYT3Woil5M0zS9Y2EbcmTzgUQwRi0CqYG8UHBPxNGFMX8SxLIxi8EbjgO9dRsrWnUYr Yp4Bqbf3oNqgI1XSaKOiQ/oJW/eZ7I+uk0gZTXDXHsQrrPE9ZDd7TGYdl2sfHKsijSD7 98CrQRUtl3kwRWwW0h9dZROjEeS6KEAaXmiXjusmgizaPhAEZDmXRzszCKKb4T4YhO48 huaw== X-Gm-Message-State: AOAM531y6xtnaBKqOleF1Cf9mQ6wxeCVN9ouovBWhXQmkGEVeKISvEIj FKz6t9tyaRGnN81KP97VHVvKzIpdKBP2XQ== X-Google-Smtp-Source: ABdhPJyq+J76gHLpln3JZEsplM+ovXJH6AdQaG55HLv9cJpdF5NGETNJmQVeoVqtoV2YZmZe7GOcPQ== X-Received: by 2002:a0c:f3d2:0:b0:456:34aa:5978 with SMTP id f18-20020a0cf3d2000000b0045634aa5978mr13519939qvm.59.1651095423111; Wed, 27 Apr 2022 14:37:03 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:d588]) by smtp.gmail.com with ESMTPSA id b9-20020a05620a0f8900b0069e84c5352asm8370423qkn.47.2022.04.27.14.37.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Apr 2022 14:37:02 -0700 (PDT) Date: Wed, 27 Apr 2022 17:36:26 -0400 From: Johannes Weiner To: Minchan Kim Cc: Andrew Morton , Michal Hocko , Roman Gushchin , Shakeel Butt , Seth Jennings , Dan Streetman , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 4/5] mm: zswap: add basic meminfo and vmstat coverage Message-ID: References: <20220427160016.144237-1-hannes@cmpxchg.org> <20220427160016.144237-5-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 27, 2022 at 05:20:31PM -0400, Johannes Weiner wrote: > On Wed, Apr 27, 2022 at 01:29:34PM -0700, Minchan Kim wrote: > > Hi Johannes, > > > > On Wed, Apr 27, 2022 at 12:00:15PM -0400, Johannes Weiner wrote: > > > Currently it requires poking at debugfs to figure out the size and > > > population of the zswap cache on a host. There are no counters for > > > reads and writes against the cache. As a result, it's difficult to > > > understand zswap behavior on production systems. > > > > > > Print zswap memory consumption and how many pages are zswapped out in > > > /proc/meminfo. Count zswapouts and zswapins in /proc/vmstat. > > > > > > Signed-off-by: Johannes Weiner > > > --- > > > fs/proc/meminfo.c | 7 +++++++ > > > include/linux/swap.h | 5 +++++ > > > include/linux/vm_event_item.h | 4 ++++ > > > mm/vmstat.c | 4 ++++ > > > mm/zswap.c | 13 ++++++------- > > > 5 files changed, 26 insertions(+), 7 deletions(-) > > > > > > diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c > > > index 6fa761c9cc78..6e89f0e2fd20 100644 > > > --- a/fs/proc/meminfo.c > > > +++ b/fs/proc/meminfo.c > > > @@ -86,6 +86,13 @@ static int meminfo_proc_show(struct seq_file *m, void *v) > > > > > > show_val_kb(m, "SwapTotal: ", i.totalswap); > > > show_val_kb(m, "SwapFree: ", i.freeswap); > > > +#ifdef CONFIG_ZSWAP > > > + seq_printf(m, "Zswap: %8lu kB\n", > > > + (unsigned long)(zswap_pool_total_size >> 10)); > > > + seq_printf(m, "Zswapped: %8lu kB\n", > > > + (unsigned long)atomic_read(&zswap_stored_pages) << > > > + (PAGE_SHIFT - 10)); > > > +#endif > > > > I agree it would be very handy to have the memory consumption in meminfo > > > > https://lore.kernel.org/all/YYwZXrL3Fu8%2FvLZw@google.com/ > > > > If we really go this Zswap only metric instead of general term > > "Compressed", I'd like to post maybe "Zram:" with same reason > > in this patchset. Do you think that's better idea instead of > > introducing general term like "Compressed:" or something else? > > I'm fine with changing it to Compressed. If somebody cares about a > more detailed breakdown, we can add Zswap, Zram subsets as needed. It does raise the question what to do about cgroup, though. Should the control files (memory.zswap.current & memory.zswap.max) apply to zram in the future? If so, we should rename them, too. I'm not too familiar with zram, maybe you can provide some background. AFAIU, Google uses zram quite widely; all the more confusing why there is no container support for it yet. Could you shed some light? Thanks