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 92E63C433F5 for ; Tue, 11 Oct 2022 01:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230481AbiJKB0U (ORCPT ); Mon, 10 Oct 2022 21:26:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231200AbiJKB0C (ORCPT ); Mon, 10 Oct 2022 21:26:02 -0400 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 E18718285A for ; Mon, 10 Oct 2022 18:25:40 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id EC6BD34BDDD2; Mon, 10 Oct 2022 18:01:05 -0700 (PDT) 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 Subject: [RFC PATCH v1 02/14] mm: Add new knob /sys/class/bdi//strict_limit Date: Mon, 10 Oct 2022 18:00:32 -0700 Message-Id: <20221011010044.851537-3-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221011010044.851537-1-shr@devkernel.io> References: <20221011010044.851537-1-shr@devkernel.io> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Add a new knob to /sys/class/bdi//strict_limit. This new knob allows to set/unset the flag BDI_CAP_STRICTLIMIT in the bdi capabilities. 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 de65cb1e5f76..f9aaa14ad98f 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -209,11 +209,40 @@ static ssize_t stable_pages_required_show(struct de= vice *dev, } static DEVICE_ATTR_RO(stable_pages_required); =20 +static ssize_t strict_limit_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct backing_dev_info *bdi =3D dev_get_drvdata(dev); + unsigned int strict_limit; + ssize_t ret; + + ret =3D kstrtouint(buf, 10, &strict_limit); + if (ret < 0) + return ret; + + ret =3D bdi_set_strict_limit(bdi, strict_limit); + if (!ret) + ret =3D count; + + return ret; +} + +static ssize_t strict_limit_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct backing_dev_info *bdi =3D dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", + !!(bdi->capabilities & BDI_CAP_STRICTLIMIT)); +} +static DEVICE_ATTR_RW(strict_limit); + 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_stable_pages_required.attr, + &dev_attr_strict_limit.attr, NULL, }; ATTRIBUTE_GROUPS(bdi_dev); --=20 2.30.2