From patchwork Tue Oct 11 01:00:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13003480 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B05C1C433FE for ; Tue, 11 Oct 2022 01:01:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3EC508E0002; Mon, 10 Oct 2022 21:01:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3756E6B0080; Mon, 10 Oct 2022 21:01:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 177CB8E0002; Mon, 10 Oct 2022 21:01:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 036BB8E0001 for ; Mon, 10 Oct 2022 21:01:23 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id BFCD980FE6 for ; Tue, 11 Oct 2022 01:01:22 +0000 (UTC) X-FDA: 80006865204.07.23A3EEB Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) by imf05.hostedemail.com (Postfix) with ESMTP id 5AA34100025 for ; Tue, 11 Oct 2022 01:01:22 +0000 (UTC) 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 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1665450082; a=rsa-sha256; cv=none; b=snz2Cxfzmq2l0Gp9iydFJe1DQbG/qQtGHqGYoTK/cKHYTRtZUUOQIzlqt3Br/r5vptAE2W 0lwoIToQmzv0BXCjarIt/o2Ix0CO9rJXGcGmZovIGkIsqCZtMl+zeJTHkSPQ9AkKp6n5kY i36JjUGLvl/t61LesQJtS85xB1ncYmI= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=none; dmarc=none; spf=neutral (imf05.hostedemail.com: 66.220.144.178 is neither permitted nor denied by domain of shr@devkernel.io) smtp.mailfrom=shr@devkernel.io ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1665450082; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yA3Fy5aq+RPK3mUVVAXlmIRHSh44Hb3uSGxFbumPhLE=; b=uZyRiWukEMWZsQhfXrjHZyFRz2s1otk+55TKHw5rdTILDqilr42RHnX+HLV5TK5MrDD1S3 bRvnA7F7BgP/JIT/tEKqgQVdpuhkr7XRV6jt6PIus36NW9Txmbyb4GaoSLyaniROYRVMKz FckgeUAUXrW6axqePbbZhSJnrZi6aos= Authentication-Results: imf05.hostedemail.com; dkim=none; dmarc=none; spf=neutral (imf05.hostedemail.com: 66.220.144.178 is neither permitted nor denied by domain of shr@devkernel.io) smtp.mailfrom=shr@devkernel.io X-Stat-Signature: ycjofrwibcekgu6795uudkweazso31pp X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 5AA34100025 X-Rspam-User: X-HE-Tag: 1665450082-200014 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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_ratio); int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); +int bdi_set_max_bytes(struct backing_dev_info *bdi, unsigned long long max_bytes); int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit); /* 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; +static int bdi_check_pages_limit(unsigned long pages) +{ + unsigned long max_dirty_pages = 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 = (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); +int bdi_set_max_bytes(struct backing_dev_info *bdi, unsigned long long max_bytes) +{ + int ret; + unsigned long pages = max_bytes >> PAGE_SHIFT; + unsigned long max_ratio; + + ret = bdi_check_pages_limit(pages); + if (ret) + return ret; + + max_ratio = 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 strict_limit) { if (strict_limit > 1)