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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 C2209C04EB9 for ; Mon, 3 Dec 2018 06:02:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 760F620851 for ; Mon, 3 Dec 2018 06:02:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TIszrXm4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 760F620851 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1725843AbeLCGCS (ORCPT ); Mon, 3 Dec 2018 01:02:18 -0500 Received: from mail-pl1-f196.google.com ([209.85.214.196]:38274 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725819AbeLCGCS (ORCPT ); Mon, 3 Dec 2018 01:02:18 -0500 Received: by mail-pl1-f196.google.com with SMTP id e5so5895876plb.5 for ; Sun, 02 Dec 2018 22:02:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=KvOLLYtosfl9evOE75aR4QwQpjj3V6YvB33Oi+VUiiE=; b=TIszrXm4p0cDEemFF1HIeB39YpvhTy+qNr7Q0H29c/zChAaPH+MhSXYqpoLsA76NRt Cm0nsqrwFfC/F/zTUbCKmN1r+658s8/nYO6SHeJo+0Y8FpZaiMirSP/bMWZ3izn8YhYX HymASgWQqZ2vb7k05tJSqT4cQQM/8TN+efmjAchGPHro7F4xE5DMeW9NUAy/uY/WUyFC aShqMjXBGTJo1FEjNpfBkkmeev+uMwkAc+B2GpIs2dmdaAcnw0bDSx8rS57wR9QC2IoB I0MkHpsmVWoxlAX5KGoZcDwVoKygj1i0ZG3qyNu+B9jnKxIUSWh+7A5H+bEd2QrGrnAu 8mZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=KvOLLYtosfl9evOE75aR4QwQpjj3V6YvB33Oi+VUiiE=; b=S1poKxBTwdFxPrp+SRkoCtzY+so2o78fq6W4xwR8ntJqNV9SJRg4068gNFgUrUl9NJ CYsKSApi8+7WpeA1ryyGd05zm2eMy86C4G5CaBYOsh6G8LOep5K992lzKCVoriPNwXFi tx7qP2Ri1CEAypt2aNB24bx/bkgMH90kWzABbnyZPFjiCtQ7MKJ18dHO3+hasmnhEVVV ueEqzxTLGGNPvg4Jt8/z6DYe1Vrbili08JzwePFf/s1qcWnJDV7O9eJBkeDjo8NryVGK 48a+dePGBLesa0CvgO2iPu0OSmT0eSyADMuJsvS1wN8fevF4eXqrewCsGux1bNqbBcJ5 Y0Jw== X-Gm-Message-State: AA+aEWbOlKPTJEl3LtDW6k5ouYBICNTEZhr7pijX97p2oKFhgwdwnLsS qvgIpaVQFXRgUXIputnjpBM= X-Google-Smtp-Source: AFSGD/WQnHTJolfZQYzOazcHovGKPzinhhsC+U3F7w5qudLEfald0BVMQawx39KVuVdfHKxqg1JQ4Q== X-Received: by 2002:a17:902:b118:: with SMTP id q24mr14881114plr.209.1543816932333; Sun, 02 Dec 2018 22:02:12 -0800 (PST) Received: from localhost ([175.223.22.143]) by smtp.gmail.com with ESMTPSA id j14sm16502452pfn.175.2018.12.02.22.02.10 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 02 Dec 2018 22:02:11 -0800 (PST) Date: Mon, 3 Dec 2018 15:02:08 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Andrew Morton , LKML , Joey Pabalinas , Sergey Senozhatsky Subject: Re: [PATCH v4 7/7] zram: writeback throttle Message-ID: <20181203060208.GE427@jagdpanzerIV> References: <20181203024045.153534-1-minchan@kernel.org> <20181203024045.153534-8-minchan@kernel.org> <20181203055026.GD427@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181203055026.GD427@jagdpanzerIV> User-Agent: Mutt/1.11.0 (2018-11-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (12/03/18 14:50), Sergey Senozhatsky wrote: > On (12/03/18 11:40), Minchan Kim wrote: > [..] > > + down_read(&zram->init_lock); > > + atomic64_set(&zram->stats.bd_wb_limit, val); > > + if (val == 0) > > + zram->stop_writeback = false; > > + up_read(&zram->init_lock); > > [..] > > > + if (zram->stop_writeback) { > > + ret = -EIO; > > + break; > > + } > > + > > if (!blk_idx) { > > blk_idx = alloc_block_bdev(zram); > > if (!blk_idx) { > > @@ -694,6 +732,11 @@ static ssize_t writeback_store(struct device *dev, > > zram_set_element(zram, index, blk_idx); > > blk_idx = 0; > > atomic64_inc(&zram->stats.pages_stored); > > + if (atomic64_add_unless(&zram->stats.bd_wb_limit, > > + -1 << (PAGE_SHIFT - 12), 0)) { > > + if (atomic64_read(&zram->stats.bd_wb_limit) == 0) > > + zram->stop_writeback = true; > > + } > > Do we need ->stop_writeback? It should be identical to > > atomic64_read(&zram->stats.bd_wb_limit) == 0 Seems like I misread writeback_limit_store() a bit. So, if I want to, say, let only 10M of writteback pages, I need to do echo 0 > writeback_limit echo 10M > writeback_limit_store // memparse format is for // simplicity only; I know // it should be in 4K units. every day. How about dropping the "echo 0" and ->stop_writeback? So then we can just do echo 10M > writeback_limit_store every day: if we have ->bd_wb_limit budget then we writeback, otherwise we don't. -ss