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 AEC6FC433EF for ; Fri, 3 Jun 2022 09:55:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243255AbiFCJzV (ORCPT ); Fri, 3 Jun 2022 05:55:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236071AbiFCJzQ (ORCPT ); Fri, 3 Jun 2022 05:55:16 -0400 Received: from mail-lj1-x22e.google.com (mail-lj1-x22e.google.com [IPv6:2a00:1450:4864:20::22e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B289F3AA4D; Fri, 3 Jun 2022 02:55:14 -0700 (PDT) Received: by mail-lj1-x22e.google.com with SMTP id q1so7894763ljb.5; Fri, 03 Jun 2022 02:55:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=OWftr5rdooB1seu2CxMvWy4qJk9OeiT3kgBXgjqZdPg=; b=ShCcYVwxNf9xqvzDmLZrM4BHJ0z+7tlnyFxgGORXdxDR5cDAhS+v6fvTqXwWkb+Af4 2y/+GlCQYSH6qUSbjlzcLF2MfW8w8SWXOjphqQAcnQHOijj7+AoCUhl4SNr3D/QcpWsV sRG5Cx5WxwkSGi757m/HUMwYmNwqI/HvAC04cpM9PQEPSFR3lvynH9MY+CCDYbELf0KT nKUqa7q1EHmizxWjDXr6y0Nf5zi0dZa6vqv+/VesFrhuXlwkHe2vzGwCmMy8yoOKuWFx Kw2tTmGVUP5XcWENKifidR/KTRb874f9Mw+Xe8gS1UKRdX2TioLTXbY+3rE5n13HyRRV VfUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=OWftr5rdooB1seu2CxMvWy4qJk9OeiT3kgBXgjqZdPg=; b=A2pm+7wQib6FI/a7aTLQR8Jwv85Gi0L/SLVPZjvMgucVRN9ppYMcYfI0nycK5JOJOd RB3+f2WOAngfAvrzfN5dJixxUhIPOfc9cv7h/W/dSheLJh/J6UbqmCPsYxBSU97jwhIW xhEylWuzAoOZ/A3qKlm3Ay7Ly+ibb5xbOMvUyNVwsAnIjDnyVKp2vkHUv8AeIo2KUfbZ NPtgtDxAtrg9iOqJJZEWyI1NwWpDvxTGP9txMAzUQOEllX6PSDfRJ81CMz3+rXhmKs3P NWlwKteGZ460U47PlOX9zHF3ea4ZquRFRhyK7IJtpQqngfBm+v4Pan3nnwhNNH2y8fcI dTxw== X-Gm-Message-State: AOAM533D/bwLcID3vjb+C03gBPpGkG6AeQt8d/d2jbmUt/VaVFJqozlm j274ZCM5QCp2L+qgwU0FShckLXlFU7VNjg== X-Google-Smtp-Source: ABdhPJwFPYGwdKJjJYBBZKPQnuxSXZum+xOwCTGSjAvuv3dWejOJbQB/6YmuhueXE+AvjG6HmoVoeQ== X-Received: by 2002:a2e:9584:0:b0:255:829e:590a with SMTP id w4-20020a2e9584000000b00255829e590amr473270ljh.170.1654250113061; Fri, 03 Jun 2022 02:55:13 -0700 (PDT) Received: from pc638.lan ([155.137.26.201]) by smtp.gmail.com with ESMTPSA id l26-20020a19495a000000b004790230b032sm1504717lfj.40.2022.06.03.02.55.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Jun 2022 02:55:12 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Fri, 3 Jun 2022 11:55:10 +0200 To: Joel Fernandes Cc: "Uladzislau Rezki (Sony)" , LKML , RCU , "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Oleksiy Avramchenko Subject: Re: [PATCH 2/2] rcu/kvfree: Introduce KFREE_DRAIN_JIFFIES_[MAX/MIN] interval Message-ID: References: <20220602080644.432156-1-urezki@gmail.com> <20220602080644.432156-2-urezki@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 02, 2022 at 11:32:23PM +0000, Joel Fernandes wrote: > On Thu, Jun 02, 2022 at 10:06:44AM +0200, Uladzislau Rezki (Sony) wrote: > > Currently the monitor work is scheduled with a fixed interval that > > is HZ/20 or each 50 milliseconds. The drawback of such approach is > > a low utilization of page slot in some scenarios. The page can store > > up to 512 records. For example on Android system it can look like: > > > > > > kworker/3:0-13872 [003] .... 11286.007048: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000026522604 nr_records=1 > > kworker/3:0-13872 [003] .... 11286.015638: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000095ed6fca nr_records=2 > > kworker/1:2-20434 [001] .... 11286.051230: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000044872ffd nr_records=1 > > kworker/1:2-20434 [001] .... 11286.059322: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000026522604 nr_records=2 > > kworker/0:1-20052 [000] .... 11286.095295: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000044872ffd nr_records=2 > > kworker/0:1-20052 [000] .... 11286.103418: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000cbcf05db nr_records=1 > > kworker/2:3-14372 [002] .... 11286.135155: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000095ed6fca nr_records=2 > > kworker/2:3-14372 [002] .... 11286.135198: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000044872ffd nr_records=1 > > kworker/1:2-20434 [001] .... 11286.155377: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000cbcf05db nr_records=5 > > kworker/2:3-14372 [002] .... 11286.167181: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000026522604 nr_records=5 > > kworker/1:2-20434 [001] .... 11286.179202: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x000000008ef95e14 nr_records=1 > > kworker/2:3-14372 [002] .... 11286.187398: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000c597d297 nr_records=6 > > kworker/3:0-13872 [003] .... 11286.187445: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000050bf92e2 nr_records=3 > > kworker/1:2-20434 [001] .... 11286.198975: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x00000000cbcf05db nr_records=4 > > kworker/1:2-20434 [001] .... 11286.207203: rcu_invoke_kfree_bulk_callback: rcu_preempt bulk=0x0000000095ed6fca nr_records=4 > > > > > > where a page only carries few records to reclaim a memory. In order to > > improve batching and make utilization more efficient the patch introduces > > a drain interval that can be set either to KFREE_DRAIN_JIFFIES_MAX or > > KFREE_DRAIN_JIFFIES_MIN. It is adjusted if a flood is detected, in this > > case a memory reclaim occurs more often whereas in mostly idle cases the > > interval is set to its maximum timeout that improves the utilization of > > page slots. > > > > Signed-off-by: Uladzislau Rezki (Sony) > > Reviewed-by: Joel Fernandes (Google) > Thanks! This patch makes the interval hard-coded in some sense so you can not change it in runtime, only recompilation. If there is a need or request we can make both as module_param(). If we are to do that we can just add one extra patch on top of it. -- Uladzislau Rezki