From patchwork Mon Oct 17 18:13:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009243 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 4C847C4332F for ; Mon, 17 Oct 2022 18:16:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229592AbiJQSQf (ORCPT ); Mon, 17 Oct 2022 14:16:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230040AbiJQSQe (ORCPT ); Mon, 17 Oct 2022 14:16:34 -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 1BB8B74BBC for ; Mon, 17 Oct 2022 11:16:33 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 1177939C99B4; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 01/14] mm: add bdi_set_strict_limit() function Date: Mon, 17 Oct 2022 11:13:24 -0700 Message-Id: <20221017181337.3884657-2-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This adds the bdi_set_strict_limit function to be able to set/unset the BDI_CAP_STRICTLIMIT flag. Signed-off-by: Stefan Roesch --- include/linux/backing-dev.h | 1 + mm/page-writeback.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 439815cc1ab9..9c984ffc8a0a 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -104,6 +104,7 @@ static inline unsigned long wb_stat_error(void) 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_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit); /* * Flags in backing_dev_info::capability diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 7e9d8d857ecc..e22aae0ecacd 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -698,6 +698,22 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) } EXPORT_SYMBOL(bdi_set_max_ratio); +int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit) +{ + if (strict_limit > 1) + return -EINVAL; + + spin_lock_bh(&bdi_lock); + if (strict_limit) + bdi->capabilities |= BDI_CAP_STRICTLIMIT; + else + bdi->capabilities &= ~BDI_CAP_STRICTLIMIT; + spin_unlock_bh(&bdi_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(bdi_set_strict_limit); + static unsigned long dirty_freerun_ceiling(unsigned long thresh, unsigned long bg_thresh) { From patchwork Mon Oct 17 18:13:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009245 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 1CBBAC43217 for ; Mon, 17 Oct 2022 18:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230044AbiJQSQj (ORCPT ); Mon, 17 Oct 2022 14:16:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230040AbiJQSQi (ORCPT ); Mon, 17 Oct 2022 14:16:38 -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 DDB1074B95 for ; Mon, 17 Oct 2022 11:16:37 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 1802C39C99B6; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 02/14] mm: add knob /sys/class/bdi//strict_limit Date: Mon, 17 Oct 2022 11:13:25 -0700 Message-Id: <20221017181337.3884657-3-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 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 c30419a5e119..a0899cce72ef 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -209,11 +209,40 @@ static ssize_t stable_pages_required_show(struct device *dev, } static DEVICE_ATTR_RO(stable_pages_required); +static ssize_t strict_limit_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + unsigned int strict_limit; + ssize_t ret; + + ret = kstrtouint(buf, 10, &strict_limit); + if (ret < 0) + return ret; + + ret = bdi_set_strict_limit(bdi, strict_limit); + if (!ret) + ret = count; + + return ret; +} + +static ssize_t strict_limit_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct backing_dev_info *bdi = 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[] = { &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); From patchwork Mon Oct 17 18:13:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009244 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 D45B5C43219 for ; Mon, 17 Oct 2022 18:16:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229978AbiJQSQf (ORCPT ); Mon, 17 Oct 2022 14:16:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230043AbiJQSQe (ORCPT ); Mon, 17 Oct 2022 14:16:34 -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 333E774CC5 for ; Mon, 17 Oct 2022 11:16:33 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 1D71F39C99B8; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 03/14] mm: document /sys/class/bdi//strict_limit knob Date: Mon, 17 Oct 2022 11:13:26 -0700 Message-Id: <20221017181337.3884657-4-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This documents the new /sys/class/bdi//strict_limit knob. Signed-off-by: Stefan Roesch --- Documentation/ABI/testing/sysfs-class-bdi | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index 6d2a2fc189dd..68b5d4018c2f 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -55,6 +55,17 @@ Description: mount that is prone to get stuck, or a FUSE mount which cannot be trusted to play fair. + (read-write) +What: /sys/class/bdi//strict_limit +Date: October 2022 +Contact: Stefan Roesch +Description: + Forces per-BDI checks for the share of given device in the write-back + cache even before the global background dirty limit is reached. This + is useful in situations where the global limit is much higher than + affordable for given relatively slow (or untrusted) device. Turning + strictlimit on has no visible effect if max_ratio is equal to 100%. + (read-write) What: /sys/class/bdi//stable_pages_required Date: January 2008 From patchwork Mon Oct 17 18:13:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009246 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 ACA1CC4321E for ; Mon, 17 Oct 2022 18:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230070AbiJQSQk (ORCPT ); Mon, 17 Oct 2022 14:16:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230021AbiJQSQi (ORCPT ); Mon, 17 Oct 2022 14:16:38 -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 E616E74CC5 for ; Mon, 17 Oct 2022 11:16:37 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 232EB39C99BA; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 04/14] mm: use part per 1000 for bdi ratios. Date: Mon, 17 Oct 2022 11:13:27 -0700 Message-Id: <20221017181337.3884657-5-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org To get finer granularity for ratio calculations use part per 1000 instead of percentiles. This is especially important if we want to automatically convert byte values to ratios. Otherwise the values that are actually used can be quite different. This is also important for machines with more main memory (1% of 256GB is already 2.5GB). Signed-off-by: Stefan Roesch --- include/linux/backing-dev.h | 3 +++ mm/backing-dev.c | 6 +++--- mm/page-writeback.c | 15 +++++++++------ 3 files changed, 15 insertions(+), 9 deletions(-) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 9c984ffc8a0a..19fe0e605ed8 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -102,6 +102,9 @@ static inline unsigned long wb_stat_error(void) #endif } +/* BDI ratio is expressed as part per 1000 for finer granularity. */ +#define BDI_RATIO_SCALE 10 + 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_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit); diff --git a/mm/backing-dev.c b/mm/backing-dev.c index a0899cce72ef..90fa517123dc 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -178,7 +178,7 @@ static ssize_t min_ratio_store(struct device *dev, return ret; } -BDI_SHOW(min_ratio, bdi->min_ratio) +BDI_SHOW(min_ratio, bdi->min_ratio / BDI_RATIO_SCALE) static ssize_t max_ratio_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) @@ -197,7 +197,7 @@ static ssize_t max_ratio_store(struct device *dev, return ret; } -BDI_SHOW(max_ratio, bdi->max_ratio) +BDI_SHOW(max_ratio, bdi->max_ratio / BDI_RATIO_SCALE) static ssize_t stable_pages_required_show(struct device *dev, struct device_attribute *attr, @@ -809,7 +809,7 @@ int bdi_init(struct backing_dev_info *bdi) kref_init(&bdi->refcnt); bdi->min_ratio = 0; - bdi->max_ratio = 100; + bdi->max_ratio = 100 * BDI_RATIO_SCALE; bdi->max_prop_frac = FPROP_FRAC_BASE; INIT_LIST_HEAD(&bdi->bdi_list); INIT_LIST_HEAD(&bdi->wb_list); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index e22aae0ecacd..4d5383d4da45 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -197,7 +197,7 @@ static void wb_min_max_ratio(struct bdi_writeback *wb, min *= this_bw; min = div64_ul(min, tot_bw); } - if (max < 100) { + if (max < 100 * BDI_RATIO_SCALE) { max *= this_bw; max = div64_ul(max, tot_bw); } @@ -655,6 +655,8 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) unsigned int delta; int ret = 0; + min_ratio *= BDI_RATIO_SCALE; + spin_lock_bh(&bdi_lock); if (min_ratio > bdi->max_ratio) { ret = -EINVAL; @@ -665,7 +667,7 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) bdi->min_ratio = min_ratio; } else { delta = min_ratio - bdi->min_ratio; - if (bdi_min_ratio + delta < 100) { + if (bdi_min_ratio + delta < 100 * BDI_RATIO_SCALE) { bdi_min_ratio += delta; bdi->min_ratio = min_ratio; } else { @@ -684,6 +686,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) if (max_ratio > 100) return -EINVAL; + max_ratio *= BDI_RATIO_SCALE; spin_lock_bh(&bdi_lock); if (bdi->min_ratio > max_ratio) { @@ -776,15 +779,15 @@ static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc) fprop_fraction_percpu(&dom->completions, dtc->wb_completions, &numerator, &denominator); - wb_thresh = (thresh * (100 - bdi_min_ratio)) / 100; + wb_thresh = (thresh * (100 * BDI_RATIO_SCALE - bdi_min_ratio)) / (100 * BDI_RATIO_SCALE); wb_thresh *= numerator; wb_thresh = div64_ul(wb_thresh, denominator); wb_min_max_ratio(dtc->wb, &wb_min_ratio, &wb_max_ratio); - wb_thresh += (thresh * wb_min_ratio) / 100; - if (wb_thresh > (thresh * wb_max_ratio) / 100) - wb_thresh = thresh * wb_max_ratio / 100; + wb_thresh += (thresh * wb_min_ratio) / (100 * BDI_RATIO_SCALE); + if (wb_thresh > (thresh * wb_max_ratio) / (100 * BDI_RATIO_SCALE)) + wb_thresh = thresh * wb_max_ratio / (100 * BDI_RATIO_SCALE); return wb_thresh; } From patchwork Mon Oct 17 18:13:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009248 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 6C258C4167D for ; Mon, 17 Oct 2022 18:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229998AbiJQSQl (ORCPT ); Mon, 17 Oct 2022 14:16:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230048AbiJQSQk (ORCPT ); Mon, 17 Oct 2022 14:16:40 -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 062EB74CC9 for ; Mon, 17 Oct 2022 11:16:38 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 28DA239C99BC; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 05/14] mm: add bdi_get_max_bytes() function Date: Mon, 17 Oct 2022 11:13:28 -0700 Message-Id: <20221017181337.3884657-6-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This adds a function to return the specified value for max_bytes. It converts the stored max_ratio of the bdi to the corresponding bytes value. It introduces the bdi_get_bytes helper function to do the conversion. This is an approximation as it is based on the value that is returned by global_dirty_limits(), which can change. The helper function will also be used by the min_bytes bdi knob. Signed-off-by: Stefan Roesch --- include/linux/backing-dev.h | 1 + mm/page-writeback.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 19fe0e605ed8..cb0e66564d4d 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -105,6 +105,7 @@ static inline unsigned long wb_stat_error(void) /* BDI ratio is expressed as part per 1000 for finer granularity. */ #define BDI_RATIO_SCALE 10 +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_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 4d5383d4da45..0b9dcf5afda2 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -650,6 +650,18 @@ void wb_domain_exit(struct wb_domain *dom) */ static unsigned int bdi_min_ratio; +static unsigned long long bdi_get_bytes(unsigned int ratio) +{ + unsigned long background_thresh; + unsigned long dirty_thresh; + unsigned long long bytes; + + global_dirty_limits(&background_thresh, &dirty_thresh); + bytes = (dirty_thresh * PAGE_SIZE * ratio) / BDI_RATIO_SCALE / 100; + + return bytes; +} + int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) { unsigned int delta; @@ -701,6 +713,12 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) } EXPORT_SYMBOL(bdi_set_max_ratio); +unsigned long long bdi_get_max_bytes(struct backing_dev_info *bdi) +{ + return bdi_get_bytes(bdi->max_ratio); +} +EXPORT_SYMBOL_GPL(bdi_get_max_bytes); + int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit) { if (strict_limit > 1) From patchwork Mon Oct 17 18:13:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009249 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 E1168C43217 for ; Mon, 17 Oct 2022 18:16:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230104AbiJQSQr (ORCPT ); Mon, 17 Oct 2022 14:16:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230043AbiJQSQr (ORCPT ); Mon, 17 Oct 2022 14:16:47 -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 D935B74CD8 for ; Mon, 17 Oct 2022 11:16:44 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 2E69439C99BE; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 06/14] mm: split off __bdi_set_max_ratio() function Date: Mon, 17 Oct 2022 11:13:29 -0700 Message-Id: <20221017181337.3884657-7-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This splits off the __bdi_set_max_ratio() function from the bdi_set_max_ratio() function. The __bdi_set_max_ratio() function will also be called from the bdi_set_max_bytes() function, which will be introduced in the next patch. Signed-off-by: Stefan Roesch --- mm/page-writeback.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 0b9dcf5afda2..8b8936603783 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -692,14 +692,10 @@ int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) return ret; } -int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) +static int __bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio) { int ret = 0; - if (max_ratio > 100) - return -EINVAL; - max_ratio *= BDI_RATIO_SCALE; - spin_lock_bh(&bdi_lock); if (bdi->min_ratio > max_ratio) { ret = -EINVAL; @@ -711,6 +707,14 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) return ret; } + +int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio) +{ + if (max_ratio > 100) + return -EINVAL; + + return __bdi_set_max_ratio(bdi, max_ratio * BDI_RATIO_SCALE); +} EXPORT_SYMBOL(bdi_set_max_ratio); unsigned long long bdi_get_max_bytes(struct backing_dev_info *bdi) From patchwork Mon Oct 17 18:13:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009250 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 5F912C433FE for ; Mon, 17 Oct 2022 18:16:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230168AbiJQSQx (ORCPT ); Mon, 17 Oct 2022 14:16:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42898 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230118AbiJQSQu (ORCPT ); Mon, 17 Oct 2022 14:16:50 -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 90EDD74CF3 for ; Mon, 17 Oct 2022 11:16:46 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 3407B39C99C0; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 07/14] mm: add bdi_set_max_bytes() function. Date: Mon, 17 Oct 2022 11:13:30 -0700 Message-Id: <20221017181337.3884657-8-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 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 cb0e66564d4d..5eb1ae3410b2 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) From patchwork Mon Oct 17 18:13:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009247 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 B2022C4167B for ; Mon, 17 Oct 2022 18:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229995AbiJQSQl (ORCPT ); Mon, 17 Oct 2022 14:16:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230043AbiJQSQk (ORCPT ); Mon, 17 Oct 2022 14:16:40 -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 0623074CC5 for ; Mon, 17 Oct 2022 11:16:38 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 39A9139C99C2; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 08/14] mm: add knob /sys/class/bdi//max_bytes Date: Mon, 17 Oct 2022 11:13:31 -0700 Message-Id: <20221017181337.3884657-9-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 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..d5f9a8a45550 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) +static ssize_t max_bytes_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct backing_dev_info *bdi = 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 = dev_get_drvdata(dev); + unsigned long long bytes; + ssize_t ret; + + ret = kstrtoull(buf, 10, &bytes); + if (ret < 0) + return ret; + + ret = bdi_set_max_bytes(bdi, bytes); + if (!ret) + ret = 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[] = { &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, From patchwork Mon Oct 17 18:13:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009254 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 B8D7BC43219 for ; Mon, 17 Oct 2022 18:16:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230206AbiJQSQz (ORCPT ); Mon, 17 Oct 2022 14:16:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230130AbiJQSQw (ORCPT ); Mon, 17 Oct 2022 14:16:52 -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 7201474CE9 for ; Mon, 17 Oct 2022 11:16:46 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 3F2D039C99C4; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 09/14] mm: document /sys/class/bdi//max_bytes knob Date: Mon, 17 Oct 2022 11:13:32 -0700 Message-Id: <20221017181337.3884657-10-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This documents the new /sys/class/bdi//max_bytes knob. Signed-off-by: Stefan Roesch --- Documentation/ABI/testing/sysfs-class-bdi | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index 68b5d4018c2f..580f723de049 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -56,6 +56,20 @@ Description: be trusted to play fair. (read-write) + +What: /sys/class/bdi//max_bytes +Date: October 2022 +Contact: Stefan Roesch +Description: + Allows limiting a particular device to use not more than the + given 'max_bytes' of the write-back cache. This is useful in + situations where we want to avoid one device taking all or + most of the write-back cache. For example in case of an NFS + mount that is prone to get stuck, a FUSE mount which cannot be + trusted to play fair, or a nbd device. + + (read-write) + What: /sys/class/bdi//strict_limit Date: October 2022 Contact: Stefan Roesch From patchwork Mon Oct 17 18:13:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009251 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 3A3BCC4332F for ; Mon, 17 Oct 2022 18:16:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230040AbiJQSQx (ORCPT ); Mon, 17 Oct 2022 14:16:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230021AbiJQSQv (ORCPT ); Mon, 17 Oct 2022 14:16:51 -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 8045474CCC for ; Mon, 17 Oct 2022 11:16:46 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 44E9F39C99C6; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 10/14] mm: add bdi_get_min_bytes() function. Date: Mon, 17 Oct 2022 11:13:33 -0700 Message-Id: <20221017181337.3884657-11-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This adds a function to return the specified value for min_bytes. It converts the stored min_ratio of the bdi to the corresponding bytes value. This is an approximation as it is based on the value that is returned by global_dirty_limits(), which can change. The returned value can be different than the value when the min_bytes value was set. Signed-off-by: Stefan Roesch --- include/linux/backing-dev.h | 1 + mm/page-writeback.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 5eb1ae3410b2..621329f25bbe 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -105,6 +105,7 @@ static inline unsigned long wb_stat_error(void) /* BDI ratio is expressed as part per 1000 for finer granularity. */ #define BDI_RATIO_SCALE 10 +unsigned long long bdi_get_min_bytes(struct backing_dev_info *bdi); 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); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index a6594ebdcbd8..a37a25994ad8 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -739,6 +739,12 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio) } EXPORT_SYMBOL(bdi_set_max_ratio); +unsigned long long bdi_get_min_bytes(struct backing_dev_info *bdi) +{ + return bdi_get_bytes(bdi->min_ratio); +} +EXPORT_SYMBOL_GPL(bdi_get_min_bytes); + unsigned long long bdi_get_max_bytes(struct backing_dev_info *bdi) { return bdi_get_bytes(bdi->max_ratio); From patchwork Mon Oct 17 18:13:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009252 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 7B6DAC433FE for ; Mon, 17 Oct 2022 18:16:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230160AbiJQSQ4 (ORCPT ); Mon, 17 Oct 2022 14:16:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230085AbiJQSQy (ORCPT ); Mon, 17 Oct 2022 14:16:54 -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 7214A74DC7 for ; Mon, 17 Oct 2022 11:16:51 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 4A81139C99C8; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 11/14] mm: split off __bdi_set_min_ratio() function Date: Mon, 17 Oct 2022 11:13:34 -0700 Message-Id: <20221017181337.3884657-12-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This splits off the __bdi_set_min_ratio() function from the bdi_set_min_ratio() function. The __bdi_set_min_ratio() function will also be called from the bdi_set_min_bytes() function, which will be introduced in the next patch. Signed-off-by: Stefan Roesch --- mm/page-writeback.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index a37a25994ad8..7733dcf96d7e 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -684,7 +684,7 @@ static unsigned long long bdi_get_bytes(unsigned int ratio) return bytes; } -int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) +static int __bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) { unsigned int delta; int ret = 0; @@ -730,6 +730,11 @@ static int __bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ra return ret; } +int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio) +{ + return __bdi_set_min_ratio(bdi, min_ratio * BDI_RATIO_SCALE); +} + int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio) { if (max_ratio > 100) From patchwork Mon Oct 17 18:13:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009253 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 F3CE9C43217 for ; Mon, 17 Oct 2022 18:16:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229934AbiJQSQz (ORCPT ); Mon, 17 Oct 2022 14:16:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230160AbiJQSQw (ORCPT ); Mon, 17 Oct 2022 14:16:52 -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 CCC5274CFB for ; Mon, 17 Oct 2022 11:16:47 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 5018B39C99CA; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 12/14] mm: add bdi_set_min_bytes() function Date: Mon, 17 Oct 2022 11:13:35 -0700 Message-Id: <20221017181337.3884657-13-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This introduces the bdi_set_min_bytes() function. The min_bytes function does not store the min_bytes value. Instead it converts the min_bytes value into the corresponding ratio value. Signed-off-by: Stefan Roesch --- include/linux/backing-dev.h | 1 + mm/page-writeback.c | 15 +++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 621329f25bbe..659e9cb8c643 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -109,6 +109,7 @@ unsigned long long bdi_get_min_bytes(struct backing_dev_info *bdi); 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_min_bytes(struct backing_dev_info *bdi, unsigned long long min_bytes); 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 7733dcf96d7e..04c4a142098b 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -750,6 +750,21 @@ unsigned long long bdi_get_min_bytes(struct backing_dev_info *bdi) } EXPORT_SYMBOL_GPL(bdi_get_min_bytes); +int bdi_set_min_bytes(struct backing_dev_info *bdi, unsigned long long min_bytes) +{ + int ret; + unsigned long pages = min_bytes >> PAGE_SHIFT; + unsigned long min_ratio; + + ret = bdi_check_pages_limit(pages); + if (ret) + return ret; + + min_ratio = bdi_ratio_from_pages(pages); + return __bdi_set_min_ratio(bdi, min_ratio); +} +EXPORT_SYMBOL_GPL(bdi_set_min_bytes); + unsigned long long bdi_get_max_bytes(struct backing_dev_info *bdi) { return bdi_get_bytes(bdi->max_ratio); From patchwork Mon Oct 17 18:13:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009255 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 DCB24C433FE for ; Mon, 17 Oct 2022 18:17:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230203AbiJQSRB (ORCPT ); Mon, 17 Oct 2022 14:17:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230021AbiJQSQ6 (ORCPT ); Mon, 17 Oct 2022 14:16:58 -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 539FC74B95 for ; Mon, 17 Oct 2022 11:16:51 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 55CBA39C99CC; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 13/14] mm: add /sys/class/bdi//min_bytes knob Date: Mon, 17 Oct 2022 11:13:36 -0700 Message-Id: <20221017181337.3884657-14-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org bdi has two existing knobs to limit the amount of dirty memory: min_ratio and max_ratio. However the granularity of the knobs is limited and often it is more convenient to specify limits in terms of bytes. This change adds the min_bytes knob. It does not store the min_bytes value, instead it converts the max_bytes value to a ratio. The value is therefore more an approximation than an absolute value. It also maintains the sum over all the bdi min_ratio values stored in the variable bdi_min_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 d5f9a8a45550..53dc46ffdb9b 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) +static ssize_t min_bytes_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%llu\n", bdi_get_min_bytes(bdi)); +} + +static ssize_t min_bytes_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + unsigned long long bytes; + ssize_t ret; + + ret = kstrtoull(buf, 10, &bytes); + if (ret < 0) + return ret; + + ret = bdi_set_min_bytes(bdi, bytes); + if (!ret) + ret = count; + + return ret; +} +DEVICE_ATTR_RW(min_bytes); + static ssize_t max_bytes_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -269,6 +297,7 @@ static struct attribute *bdi_dev_attrs[] = { &dev_attr_read_ahead_kb.attr, &dev_attr_min_ratio.attr, &dev_attr_max_ratio.attr, + &dev_attr_min_bytes.attr, &dev_attr_max_bytes.attr, &dev_attr_stable_pages_required.attr, &dev_attr_strict_limit.attr, From patchwork Mon Oct 17 18:13:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13009256 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 4CEE2C433FE for ; Mon, 17 Oct 2022 18:17:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230157AbiJQSRD (ORCPT ); Mon, 17 Oct 2022 14:17:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230284AbiJQSRB (ORCPT ); Mon, 17 Oct 2022 14:17:01 -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 3F73774CF2 for ; Mon, 17 Oct 2022 11:16:50 -0700 (PDT) Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 5B60139C99CE; Mon, 17 Oct 2022 11:13:56 -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, willy@infradead.org, hch@infradead.org Subject: [RFC PATCH v2 14/14] mm: document /sys/class/bdi//min_bytes knob Date: Mon, 17 Oct 2022 11:13:37 -0700 Message-Id: <20221017181337.3884657-15-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221017181337.3884657-1-shr@devkernel.io> References: <20221017181337.3884657-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This documents the new /sys/class/bdi//min_bytes knob. Signed-off-by: Stefan Roesch --- Documentation/ABI/testing/sysfs-class-bdi | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index 580f723de049..bec996e29565 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -57,6 +57,21 @@ Description: (read-write) +What: /sys/class/bdi//min_bytes +Date: October 2022 +Contact: Stefan Roesch +Description: + Under normal circumstances each device is given a part of the + total write-back cache that relates to its current average + writeout speed in relation to the other devices. + + The 'min_bytes' parameter allows assigning a minimum + percentage of the write-back cache to a particular device + expressed in bytes. + For example, this is useful for providing a minimum QoS. + + (read-write) + What: /sys/class/bdi//max_bytes Date: October 2022 Contact: Stefan Roesch