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 24449C4332F for ; Tue, 11 Oct 2022 01:24:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230510AbiJKBYs (ORCPT ); Mon, 10 Oct 2022 21:24:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230512AbiJKBYX (ORCPT ); Mon, 10 Oct 2022 21:24:23 -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 6EF7184E77 for ; Mon, 10 Oct 2022 18:23:46 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 143E934BDDDC; Mon, 10 Oct 2022 18:01:06 -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 07/14] mm: add bdi_set_max_bytes() function. Date: Mon, 10 Oct 2022 18:00:37 -0700 Message-Id: <20221011010044.851537-8-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 This introduces the bdi_set_max_bytes() function. The max_bytes function does not store the max_bytes value. Instead it converts the max_bytes value into the corresponding ratio value. Signed-off-by: Stefan Roesch --- include/linux/backing-dev.h | 1 + mm/page-writeback.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 94fedf66c915..a10598f90d4d 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -108,6 +108,7 @@ static inline unsigned long wb_stat_error(void) unsigned long long bdi_get_max_bytes(struct backing_dev_info *bdi); int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_rat= io); int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_rat= io); +int bdi_set_max_bytes(struct backing_dev_info *bdi, unsigned long long m= ax_bytes); int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int stri= ct_limit); =20 /* diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 8b8936603783..a6594ebdcbd8 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -650,6 +650,28 @@ void wb_domain_exit(struct wb_domain *dom) */ static unsigned int bdi_min_ratio; =20 +static int bdi_check_pages_limit(unsigned long pages) +{ + unsigned long max_dirty_pages =3D global_dirtyable_memory(); + + if (pages > max_dirty_pages / 2) + return -EINVAL; + + return 0; +} + +static unsigned long bdi_ratio_from_pages(unsigned long long pages) +{ + unsigned long background_thresh; + unsigned long dirty_thresh; + unsigned long ratio; + + global_dirty_limits(&background_thresh, &dirty_thresh); + ratio =3D (pages * 100 * BDI_RATIO_SCALE) / dirty_thresh; + + return ratio; +} + static unsigned long long bdi_get_bytes(unsigned int ratio) { unsigned long background_thresh; @@ -723,6 +745,21 @@ unsigned long long bdi_get_max_bytes(struct backing_= dev_info *bdi) } EXPORT_SYMBOL_GPL(bdi_get_max_bytes); =20 +int bdi_set_max_bytes(struct backing_dev_info *bdi, unsigned long long m= ax_bytes) +{ + int ret; + unsigned long pages =3D max_bytes >> PAGE_SHIFT; + unsigned long max_ratio; + + ret =3D bdi_check_pages_limit(pages); + if (ret) + return ret; + + max_ratio =3D bdi_ratio_from_pages(pages); + return __bdi_set_max_ratio(bdi, max_ratio); +} +EXPORT_SYMBOL_GPL(bdi_set_max_bytes); + int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int stri= ct_limit) { if (strict_limit > 1) --=20 2.30.2