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=1.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 0A1BDC43441 for ; Thu, 29 Nov 2018 01:45:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEFB220832 for ; Thu, 29 Nov 2018 01:45:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="khbhpzqv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BEFB220832 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727237AbeK2Msp (ORCPT ); Thu, 29 Nov 2018 07:48:45 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:46021 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726770AbeK2Msp (ORCPT ); Thu, 29 Nov 2018 07:48:45 -0500 Received: by mail-pl1-f195.google.com with SMTP id a14so155666plm.12 for ; Wed, 28 Nov 2018 17:45:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=nXQUdjr8mIMk9bhk9tG9P0f+M4XEdIih2ulCHESQpac=; b=khbhpzqvajd9ieD09Y15wYFJl/5FotZya/FVHwo3z6fH/trrTJtBKwjoly9DHjSXS3 7NpR9rXQYhFzHOXeDGzEbowsobPDGHOZRlnte1OtaWDkMDaZ/n7PW8iIm28SPpMB5+wT c3xTttljxBiv+9UpO8/SY69RUvoPeVM5gt6gswzAsP1rLyL/Rf4jxwLPjaFNVZjYgybw x/krHppOGCiBDnlOwj21iIBNN9zFixXrarWIrPPIrFGGbnh9BpuI988NvAQg0Y4m1UkT 7y5Jn184rlW5o2AIxdeJ/4NAwrAwGC09U3P1tyzU6V9AkmO9nZ7gRftWAp7RnUcqQ3eB c7Tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=nXQUdjr8mIMk9bhk9tG9P0f+M4XEdIih2ulCHESQpac=; b=Te/9NyHPowThr6SvOPZ3301I2/NqQeXR0aGeyy6JuIhMaYkTVh1PpTs4vZ5c3WBUHU tqBYQHCW5swevycB4A1FzzqvAwS77G9vOf7Izw5DhVg0uVyY6BGjGlboP3AV0awDzGdK eEip+d4sukbz98j7hQw3RqPREwXj/qyiDGMsnPNE8I6QsCYQKt7zVW9bRGfM3mjfKrAo mbKPMnpaUWO2Rrr2NzFDkDrbc44/NWRBlI383DI15QMXxFowZ7l/JayfzUXAcEeJ+jZ9 y1tUBwGaZla2nTDvRx4fJwC+ye3uyDVgPBh/c/u/LJmHkJQ/rzvH4KtAk3drEYbyLeLZ 5+oQ== X-Gm-Message-State: AA+aEWbWfMVng4NieKj+O5byqD2gnAW+1ek4IwNq2mMUrGIYYqqDJDif J31dhXQ7WdIyylNpiNwbJSg= X-Google-Smtp-Source: AFSGD/UJ9uX6D8xchdwRCbqiF9MO4/UIHlRjU5Jp3TVzGwhGeiFYaZrNenJvqkkelUmliB9IxNW7Gw== X-Received: by 2002:a17:902:4c08:: with SMTP id a8mr39764498ple.74.1543455907415; Wed, 28 Nov 2018 17:45:07 -0800 (PST) Received: from google.com ([2401:fa00:d:0:98f1:8b3d:1f37:3e8]) by smtp.gmail.com with ESMTPSA id m9sm231144pgd.32.2018.11.28.17.45.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 28 Nov 2018 17:45:06 -0800 (PST) Date: Thu, 29 Nov 2018 10:45:02 +0900 From: Minchan Kim To: Andrew Morton Cc: LKML , Sergey Senozhatsky Subject: Re: [PATCH v2 6/7] zram: add bd_stat statistics Message-ID: <20181129014502.GB77327@google.com> References: <20181126082813.81977-1-minchan@kernel.org> <20181126082813.81977-7-minchan@kernel.org> <20181126125833.e95a21088ae60ccc6fd55022@linux-foundation.org> <20181127020754.GB237537@google.com> <20181128153021.3f125ed82df68a29e25ce428@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181128153021.3f125ed82df68a29e25ce428@linux-foundation.org> User-Agent: Mutt/1.10.1+60 (6df12dc1) (2018-08-07) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 28, 2018 at 03:30:21PM -0800, Andrew Morton wrote: > On Tue, 27 Nov 2018 11:07:54 +0900 Minchan Kim wrote: > > > On Mon, Nov 26, 2018 at 12:58:33PM -0800, Andrew Morton wrote: > > > On Mon, 26 Nov 2018 17:28:12 +0900 Minchan Kim wrote: > > > > > > > +File /sys/block/zram/bd_stat > > > > + > > > > +The stat file represents device's backing device statistics. It consists of > > > > +a single line of text and contains the following stats separated by whitespace: > > > > + bd_count size of data written in backing device. > > > > + Unit: pages > > > > + bd_reads the number of reads from backing device > > > > + Unit: pages > > > > + bd_writes the number of writes to backing device > > > > + Unit: pages > > > > > > Using `pages' is a bad choice. And I assume this means that > > > writeback_limit is in pages as well, which is worse. > > > > > > Page sizes are not constant! We want userspace which was developed on > > > 4k pagesize to work the same on 64k pagesize. > > > > > > Arguably, we could require that well-written userspace remember to use > > > getpagesize(). However we have traditionally tried to avoid that by > > > performing the pagesize normalization within the kernel. > > > > zram works based on page so I used that term but I agree it's rather > > vague. If there is no objection, I will use (Unit: 4K) instead of > > (Unit: pages). > > Is that still true if PAGE_SIZE=64k? Oops, it will fix.