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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 8B96CC4361B for ; Tue, 15 Dec 2020 03:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BEB9223C8 for ; Tue, 15 Dec 2020 03:16:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727803AbgLODQE (ORCPT ); Mon, 14 Dec 2020 22:16:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:43126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727813AbgLODPK (ORCPT ); Mon, 14 Dec 2020 22:15:10 -0500 Date: Mon, 14 Dec 2020 19:14:28 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608002069; bh=KAw0uzsCp6yu6qdJ6LEUP7e+C6NLaXRa781LmsUFxvc=; h=From:To:Subject:In-Reply-To:From; b=QK7BNmh44Sn0KryD6ZGpNtFN17VTeMMeQN2mGf67yhygJYamBSil196muv2QNPPFN UXU2e2plMDr+xnG3n76CaDBJeqnv+MhLARhaEM0KKVNfohyui55P+97os6r/JuUecc Zd0CYLA5z9Ec8jDSf3g0WjAjUi1RrJ3L4hWYB0Qw= From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, minchan@kernel.org, mm-commits@vger.kernel.org, sergey.senozhatsky@gmail.com, torvalds@linux-foundation.org Subject: [patch 190/200] zram: support page writeback Message-ID: <20201215031428.UjWm-CT5V%akpm@linux-foundation.org> In-Reply-To: <20201214190237.a17b70ae14f129e2dca3d204@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Minchan Kim Subject: zram: support page writeback There is demand to writeback specific process pages to backing store instead of all idles pages in the system due to storage wear out concerns and to launching latency of apps which are most of the time idle but are critical for resume latency. This patch extends the writeback knob to support a specific page writeback. Link: https://lkml.kernel.org/r/20201020190506.3758660-1-minchan@kernel.org Signed-off-by: Minchan Kim Reviewed-by: Sergey Senozhatsky Signed-off-by: Andrew Morton --- Documentation/admin-guide/blockdev/zram.rst | 5 ++++ drivers/block/zram/zram_drv.c | 21 ++++++++++++++---- 2 files changed, 22 insertions(+), 4 deletions(-) --- a/Documentation/admin-guide/blockdev/zram.rst~zram-support-a-page-writeback +++ a/Documentation/admin-guide/blockdev/zram.rst @@ -334,6 +334,11 @@ Admin can request writeback of those idl With the command, zram writeback idle pages from memory to the storage. +If admin want to write a specific page in zram device to backing device, +they could write a page index into the interface. + + echo "page_index=1251" > /sys/block/zramX/writeback + If there are lots of write IO with flash device, potentially, it has flash wearout problem so that admin needs to design write limitation to guarantee storage health for entire product life. --- a/drivers/block/zram/zram_drv.c~zram-support-a-page-writeback +++ a/drivers/block/zram/zram_drv.c @@ -620,15 +620,19 @@ static int read_from_bdev_async(struct z return 1; } +#define PAGE_WB_SIG "page_index=" + +#define PAGE_WRITEBACK 0 #define HUGE_WRITEBACK 1 #define IDLE_WRITEBACK 2 + static ssize_t writeback_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { struct zram *zram = dev_to_zram(dev); unsigned long nr_pages = zram->disksize >> PAGE_SHIFT; - unsigned long index; + unsigned long index = 0; struct bio bio; struct bio_vec bio_vec; struct page *page; @@ -640,8 +644,17 @@ static ssize_t writeback_store(struct de mode = IDLE_WRITEBACK; else if (sysfs_streq(buf, "huge")) mode = HUGE_WRITEBACK; - else - return -EINVAL; + else { + if (strncmp(buf, PAGE_WB_SIG, sizeof(PAGE_WB_SIG) - 1)) + return -EINVAL; + + ret = kstrtol(buf + sizeof(PAGE_WB_SIG) - 1, 10, &index); + if (ret || index >= nr_pages) + return -EINVAL; + + nr_pages = 1; + mode = PAGE_WRITEBACK; + } down_read(&zram->init_lock); if (!init_done(zram)) { @@ -660,7 +673,7 @@ static ssize_t writeback_store(struct de goto release_init_lock; } - for (index = 0; index < nr_pages; index++) { + while (nr_pages--) { struct bio_vec bvec; bvec.bv_page = page; _