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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F4F8C433FE for ; Sat, 19 Nov 2022 01:56:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232050AbiKSB4s (ORCPT ); Fri, 18 Nov 2022 20:56:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233900AbiKSB4b (ORCPT ); Fri, 18 Nov 2022 20:56:31 -0500 Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AAFDC4C2F for ; Fri, 18 Nov 2022 17:45:41 -0800 (PST) Received: by dev0134.prn3.facebook.com (Postfix, from userid 425415) id 6B4AF19380D6; Fri, 18 Nov 2022 16:52:18 -0800 (PST) From: Stefan Roesch To: kernel-team@fb.com, linux-block@vger.kernel.org, linux-mm@kvack.org Cc: shr@devkernel.io, axboe@kernel.dk, clm@meta.com, akpm@linux-foundation.org Subject: [RFC PATCH v4 08/20] mm: add knob /sys/class/bdi//max_bytes Date: Fri, 18 Nov 2022 16:52:03 -0800 Message-Id: <20221119005215.3052436-9-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221119005215.3052436-1-shr@devkernel.io> References: <20221119005215.3052436-1-shr@devkernel.io> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This adds the new knob max_bytes to specify a dirty memory limit for the corresponding bdi. The specified bytes value is converted to a ratio. Signed-off-by: Stefan Roesch --- mm/backing-dev.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 90fa517123dc..95d3229fc81f 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -199,6 +199,34 @@ static ssize_t max_ratio_store(struct device *dev, } BDI_SHOW(max_ratio, bdi->max_ratio / BDI_RATIO_SCALE) =20 +static ssize_t max_bytes_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct backing_dev_info *bdi =3D dev_get_drvdata(dev); + + return sysfs_emit(buf, "%llu\n", bdi_get_max_bytes(bdi)); +} + +static ssize_t max_bytes_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct backing_dev_info *bdi =3D dev_get_drvdata(dev); + u64 bytes; + ssize_t ret; + + ret =3D kstrtoull(buf, 10, &bytes); + if (ret < 0) + return ret; + + ret =3D bdi_set_max_bytes(bdi, bytes); + if (!ret) + ret =3D count; + + return ret; +} +DEVICE_ATTR_RW(max_bytes); + static ssize_t stable_pages_required_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -241,6 +269,7 @@ static struct attribute *bdi_dev_attrs[] =3D { &dev_attr_read_ahead_kb.attr, &dev_attr_min_ratio.attr, &dev_attr_max_ratio.attr, + &dev_attr_max_bytes.attr, &dev_attr_stable_pages_required.attr, &dev_attr_strict_limit.attr, NULL, --=20 2.30.2