From patchwork Wed Sep 29 14:30:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brian Geffon X-Patchwork-Id: 12525659 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10CEDC433FE for ; Wed, 29 Sep 2021 14:31:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA0D8613D3 for ; Wed, 29 Sep 2021 14:31:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344479AbhI2Oc5 (ORCPT ); Wed, 29 Sep 2021 10:32:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344490AbhI2Oc5 (ORCPT ); Wed, 29 Sep 2021 10:32:57 -0400 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A6F0C06161C for ; Wed, 29 Sep 2021 07:31:16 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id 62-20020aed2044000000b002a6aa209efaso8568422qta.18 for ; Wed, 29 Sep 2021 07:31:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=rWICg8z18y6VVMgB2+FBawlhY9BT8cZzUVXfBU/5MDc=; b=lDmFatJxse2Wln+jGfebmXhp7ycDVxpvCtDN5lXIJGK6Cqt2tWheN/OsgOdlMKRBn3 nUxGAmetg2Xz+ITdJ9SZKNJfMh3K1TV+RTJD7NtJAT3S0kEXXjbnWbZVRDi7I26Gw+pA if5ye7gfxc4hg/zbooMFmMgNyOvTDMfrx3DIO3HEzzx/lkeO+wqXumwFJHc4fl+9R3oa ILTW5xhoS3B4B4qYePulahGaD7oxojtUVWeolSwhNCj9jEffJ15zn8MOJO6TDQiG5Z8C JbAshmkT9/7neyVISnTlS9aGiexK4t1ibOVGuNmYhDEBaWxngYutYMXW7lquprr+bUDS xITg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=rWICg8z18y6VVMgB2+FBawlhY9BT8cZzUVXfBU/5MDc=; b=cBVxknyk8HbHYoj/MKr8THx1WatGa727F7g/MJGH/5OLovsOfHLRNSA0IhgDiDDnxL J7qOqhOR2WWbUDYl7kDeYkR+UA+DJTiua51k7HsJzkbvxaE5lyOTsj+Fo75esnTyJlYm A3+lss+AtL6XTOirQ821fzZ/Ml4SwqSBcCOQWxBdzDBlZlyIN47Tj8h+cLSTG8LUImCE //tNmZKCv0RRRUS82jd+iXbOHM0n8bLRvgK3mfyBjLTWzkjFZdLudzQwHYSu+cZnqlN2 38wrR+mDDA1xDa0nklL5TEM0NVgJdKp67luE+aiXm7f/FAWp3B8aj6ylRFPK9acqcUl5 c3Sg== X-Gm-Message-State: AOAM533EZ422P+6amP1VmHTKu30MyqM38dNnuMk6OaHNry2W3oAhvbMz xq3155NNdDvqbi4Dx6dNJ4GU0PWGQDEZ X-Google-Smtp-Source: ABdhPJwDV7ClEvzTaenTx9rrvJz3xctvGcdzsJSql0k1qJNvj4+7OO3EWhHwlFTBoaVZ+/f8jCZSYTGTNTbo X-Received: from bg.sfo.corp.google.com ([2620:15c:11a:202:d5dd:2dee:3cc9:114]) (user=bgeffon job=sendgmr) by 2002:a05:6214:1046:: with SMTP id l6mr11763064qvr.6.1632925875212; Wed, 29 Sep 2021 07:31:15 -0700 (PDT) Date: Wed, 29 Sep 2021 07:30:56 -0700 In-Reply-To: <20210917210640.214211-1-bgeffon@google.com> Message-Id: <20210929143056.13067-1-bgeffon@google.com> Mime-Version: 1.0 References: <20210917210640.214211-1-bgeffon@google.com> X-Mailer: git-send-email 2.33.0.685.g46640cef36-goog Subject: [PATCH v6] zram: Introduce an aged idle interface From: Brian Geffon To: Andrew Morton Cc: Minchan Kim , Nitin Gupta , Sergey Senozhatsky , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-block@vger.kernel.org, Suleiman Souhlal , Jesse Barnes , Brian Geffon Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This change introduces an aged idle interface to the existing idle sysfs file for zram. When CONFIG_ZRAM_MEMORY_TRACKING is enabled the idle file now also accepts an integer argument. This integer is the age (in seconds) of pages to mark as idle. The idle file still supports 'all' as it always has. This new approach allows for much more control over which pages get marked as idle. v5 -> v6: - Sergey's cleanup suggestions. v4 -> v5: - Andrew's suggestions to use IS_ENABLED and cleanup comment. v3 -> v4: - Remove base10 restriction. v2 -> v3: - Correct unused variable warning when CONFIG_ZRAM_MEMORY_TRACKING is not enabled. v1 -> v2: - Switch to using existing idle file. - Dont compare ktime directly. Signed-off-by: Brian Geffon Acked-by: Minchan Kim --- Documentation/admin-guide/blockdev/zram.rst | 8 +++ drivers/block/zram/zram_drv.c | 62 +++++++++++++++------ 2 files changed, 54 insertions(+), 16 deletions(-) diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index 700329d25f57..3e11926a4df9 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -328,6 +328,14 @@ as idle:: From now on, any pages on zram are idle pages. The idle mark will be removed until someone requests access of the block. IOW, unless there is access request, those pages are still idle pages. +Additionally, when CONFIG_ZRAM_MEMORY_TRACKING is enabled pages can be +marked as idle based on how long (in seconds) it's been since they were +last accessed:: + + echo 86400 > /sys/block/zramX/idle + +In this example all pages which haven't been accessed in more than 86400 +seconds (one day) will be marked idle. Admin can request writeback of those idle pages at right timing via:: diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index fcaf2750f68f..4e76a75a7840 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -291,22 +291,16 @@ static ssize_t mem_used_max_store(struct device *dev, return len; } -static ssize_t idle_store(struct device *dev, - struct device_attribute *attr, const char *buf, size_t len) +/* + * Mark all pages which are older than or equal to cutoff as IDLE. + * Callers should hold the zram init lock in read mode + */ +static void mark_idle(struct zram *zram, ktime_t cutoff) { - struct zram *zram = dev_to_zram(dev); + int is_idle = 1; unsigned long nr_pages = zram->disksize >> PAGE_SHIFT; int index; - if (!sysfs_streq(buf, "all")) - return -EINVAL; - - down_read(&zram->init_lock); - if (!init_done(zram)) { - up_read(&zram->init_lock); - return -EINVAL; - } - for (index = 0; index < nr_pages; index++) { /* * Do not mark ZRAM_UNDER_WB slot as ZRAM_IDLE to close race. @@ -314,14 +308,50 @@ static ssize_t idle_store(struct device *dev, */ zram_slot_lock(zram, index); if (zram_allocated(zram, index) && - !zram_test_flag(zram, index, ZRAM_UNDER_WB)) - zram_set_flag(zram, index, ZRAM_IDLE); + !zram_test_flag(zram, index, ZRAM_UNDER_WB)) { +#ifdef CONFIG_ZRAM_MEMORY_TRACKING + is_idle = !cutoff || ktime_after(cutoff, zram->table[index].ac_time); +#endif + if (is_idle) + zram_set_flag(zram, index, ZRAM_IDLE); + } zram_slot_unlock(zram, index); } +} - up_read(&zram->init_lock); +static ssize_t idle_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + struct zram *zram = dev_to_zram(dev); + ktime_t cutoff_time = 0; + ssize_t rv = -EINVAL; - return len; + if (!sysfs_streq(buf, "all")) { + /* + * If it did not parse as 'all' try to treat it as an integer when + * we have memory tracking enabled. + */ + u64 age_sec; + + if (IS_ENABLED(CONFIG_ZRAM_MEMORY_TRACKING) && !kstrtoull(buf, 0, &age_sec)) + cutoff_time = ktime_sub(ktime_get_boottime(), + ns_to_ktime(age_sec * NSEC_PER_SEC)); + else + goto out; + } + + down_read(&zram->init_lock); + if (!init_done(zram)) + goto out_unlock; + + /* A cutoff_time of 0 marks everything as idle, this is the "all" behavior */ + mark_idle(zram, cutoff_time); + rv = len; + +out_unlock: + up_read(&zram->init_lock); +out: + return rv; } #ifdef CONFIG_ZRAM_WRITEBACK