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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 D6EADC433EF for ; Fri, 17 Sep 2021 21:07:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C155F61074 for ; Fri, 17 Sep 2021 21:07:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344305AbhIQVI2 (ORCPT ); Fri, 17 Sep 2021 17:08:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42514 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344127AbhIQVI1 (ORCPT ); Fri, 17 Sep 2021 17:08:27 -0400 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3F67C061757 for ; Fri, 17 Sep 2021 14:07:04 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id 21-20020a370815000000b003d5a81a4d12so75449753qki.3 for ; Fri, 17 Sep 2021 14:07:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=1RUt2IvhDUKLquM1kcv9z34EUuW3smlZ2afUa2bIZHg=; b=mBDQt0NeEIlmClEh53VD2jNMytDjF+f478ehVEuynsRp1GhLR4kW4nc8kdusDfUHvf W4LW2+jw6NnX+0xT/t0YI0FgaWlNSz4k+wYfcAOdpt3e8VjWs6aXixTxpA/LLckXq0Rn cNs/9yqN8XOG8iYQ/ZFT2Wtx+OVQYQfp8ScKjBhgH2WCurSVX9YukLnO4aaSLmIFfGCD qFFt5bXowqWDsbY0aywODmPFyYUVu0t33qYV+cWHIwbGZttKzyp5NWs64VZuTs0f1HdS p9xLiBUEDdLpoFo3tjY55HpoHDx/1LPaLvO/KOVUeBWpme1B+KZ5ep2WNmqKNd6aSSWU mf2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=1RUt2IvhDUKLquM1kcv9z34EUuW3smlZ2afUa2bIZHg=; b=VcEx3fLd+/c2rcXtncRx8R66lRqJbENwkT0aSNfUU540uMId0fYCgsR2FS35IT4AB1 GY48ghn2VO0xar5DmiFnUkhbhkKhT9xgIsu2EZgApno+Gc6XClkxcbo/4CXoqa/EqHYf BoTRmHJk3gWAhHZUkDVoUCYsA/X5ALhF7KeNPQmfdENTLdjWCkaFo7p6Il2BzuiyzQjQ Md36wESqWJNZ1X1XrrbV1sWftToAJp5xvW+HYMqGA0GlKgZzwhjrGKkmGyDYI84mgeqg XVSz3ZRmLfOXHFWLrhqnrsw3z/5KZkf/Yle5Pk9oCWMsqNBtIgJH7Lxr1b9dMWq17m93 rCMA== X-Gm-Message-State: AOAM533axOFGQJdUCQr3ElUgd3gsFolMS22T4kEwVB8NynGr3+j/wwjc S9WVlWUHA+L7L+jOVNskgattc13cCcPS X-Google-Smtp-Source: ABdhPJwuhT21pwC4HbZIBKQBRcwBDZARIC5/y4SimyqpdTFIflIFMCV85KKaekuSd1m8ES8YnF7vy4AzjNZD X-Received: from bg.sfo.corp.google.com ([2620:15c:11a:202:4316:322d:79c2:7a14]) (user=bgeffon job=sendgmr) by 2002:a0c:d6cd:: with SMTP id l13mr13168135qvi.24.1631912824132; Fri, 17 Sep 2021 14:07:04 -0700 (PDT) Date: Fri, 17 Sep 2021 14:06:40 -0700 Message-Id: <20210917210640.214211-1-bgeffon@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.33.0.464.g1972c5931b-goog Subject: [PATCH] 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org This change introduces a new sysfs file for the zram idle interface. The current idle interface has only a single mode "all." This is severely limiting in that it requires that you have the foresight to know that you'll want to have pages idle at some point in the future and forces the user to mark everything as idle. This new proposed file idle_aged takes a single integer argument which represents the age of the pages (in seconds since access) to mark as idle. Because it requires accessed tracking it is only enabled when CONFIG_ZRAM_MEMORY_TRACKING is enabled. There are a few reasons why this is being proposed as a new file rather than extending the existing file. The first reason is that it wouldn't allow more code sharing as this change already refactors the existing code to do so. Secondly, having a standalone file allows a caller to quickly check if this idle_aged interface is supported. Finally, it simplifies the parsing logic because now you only need to parse an int rather than more complex logic which would need to parse things like "aged 50." Signed-off-by: Brian Geffon --- Documentation/admin-guide/blockdev/zram.rst | 11 ++- drivers/block/zram/zram_drv.c | 75 +++++++++++++++++---- 2 files changed, 70 insertions(+), 16 deletions(-) diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index 700329d25f57..ecd1c4916a1c 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -209,6 +209,8 @@ compact WO trigger memory compaction debug_stat RO this file is used for zram debugging purposes backing_dev RW set up backend storage for zram to write out idle WO mark allocated slot as idle +idle_aged WO mark allocated slot older than 'age' seconds + as idle (see later) ====================== ====== =============================================== @@ -325,8 +327,13 @@ as idle:: echo all > /sys/block/zramX/idle -From now on, any pages on zram are idle pages. The idle mark -will be removed until someone requests access of the block. +Alternatively if the config option CONFIG_ZRAM_MEMORY_TRACKING is enabled +the idle_aged interface can be used to mark only pages older than 'age' +seconds as idle:: + + echo 86400 > /sys/block/zramX/idle_aged + +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. 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..a371dc0edf9d 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. @@ -314,16 +308,63 @@ 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 || cutoff >= zram->table[index].ac_time); +#endif + if (is_idle) + zram_set_flag(zram, index, ZRAM_IDLE); + } zram_slot_unlock(zram, index); } +} + +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); + + if (!sysfs_streq(buf, "all")) + return -EINVAL; + + down_read(&zram->init_lock); + if (!init_done(zram)) { + up_read(&zram->init_lock); + return -EINVAL; + } + /* Mark everything as idle */ + mark_idle(zram, 0); up_read(&zram->init_lock); return len; } +#ifdef CONFIG_ZRAM_MEMORY_TRACKING +static ssize_t idle_aged_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; + u64 age_sec; + ssize_t rv = -EINVAL; + + down_read(&zram->init_lock); + if (!init_done(zram)) + goto out; + + if (kstrtoull(buf, 10, &age_sec)) + goto out; + + rv = len; + cutoff_time = ktime_sub(ktime_get_boottime(), ns_to_ktime(age_sec * NSEC_PER_SEC)); + mark_idle(zram, cutoff_time); +out: + up_read(&zram->init_lock); + return rv; +} +#endif + #ifdef CONFIG_ZRAM_WRITEBACK static ssize_t writeback_limit_enable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) @@ -1840,6 +1881,9 @@ static DEVICE_ATTR_WO(reset); static DEVICE_ATTR_WO(mem_limit); static DEVICE_ATTR_WO(mem_used_max); static DEVICE_ATTR_WO(idle); +#ifdef CONFIG_ZRAM_MEMORY_TRACKING +static DEVICE_ATTR_WO(idle_aged); +#endif static DEVICE_ATTR_RW(max_comp_streams); static DEVICE_ATTR_RW(comp_algorithm); #ifdef CONFIG_ZRAM_WRITEBACK @@ -1857,6 +1901,9 @@ static struct attribute *zram_disk_attrs[] = { &dev_attr_mem_limit.attr, &dev_attr_mem_used_max.attr, &dev_attr_idle.attr, +#ifdef CONFIG_ZRAM_MEMORY_TRACKING + &dev_attr_idle_aged.attr, +#endif &dev_attr_max_comp_streams.attr, &dev_attr_comp_algorithm.attr, #ifdef CONFIG_ZRAM_WRITEBACK -- 2.33.0.464.g1972c5931b-goog