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 6E474C001DB for ; Tue, 8 Aug 2023 17:59:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235199AbjHHR74 (ORCPT ); Tue, 8 Aug 2023 13:59:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233328AbjHHR7Y (ORCPT ); Tue, 8 Aug 2023 13:59:24 -0400 Received: from mail-yb1-xb34.google.com (mail-yb1-xb34.google.com [IPv6:2607:f8b0:4864:20::b34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02DE22CC4C for ; Tue, 8 Aug 2023 09:26:53 -0700 (PDT) Received: by mail-yb1-xb34.google.com with SMTP id 3f1490d57ef6-d2b8437d825so5808664276.3 for ; Tue, 08 Aug 2023 09:26:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1691511979; x=1692116779; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=rzvjGxgEq+LtZZdyPTPHKgoOYqzBn/ItwHuccLXsw3U=; b=fBE3x/l+C3VKo8FO3fVS/iF/fhcHbbEsdOdaGoNacCkajhWuI4HnRWX3Ogne/9fXwS a7i7rTxroNcwMYX+3cngO8f1nOM7zbBEJeDAfzEPc649RLSEsaXWDaRX2dkpNGrkKhBO G5Kdxj/omgychPGrm17b11KB3pzbChkm/9ZBEtB1mBGASfURxAzkLfWpJI4hnbIZ4ISR kH+kikx1KlgERen42bkEPu371Isj82R/4UOZUCz/z6vFfjcATK2KE1/+RgzLXsgVDfjx MoKgNmGcsshlTR7OQgubYKJyQ5hQLGEu54e69okkfdHSmMDZ4H8SKOG75snAXknO1Chl Ma2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691511979; x=1692116779; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=rzvjGxgEq+LtZZdyPTPHKgoOYqzBn/ItwHuccLXsw3U=; b=cemtXYuLaAOlzsy4gzwbDwVVPwKFKz/uh6O0zCaEi1qucUB04G33nRgeVRH4sDiThy hfk/4ggR6mTpU/QkyWpls4YMY2bRN7TNtGtOfBO5zAzuLar2Qn/Odu3teSuBGlbvb8eV 3EuT+EQI7JZ93dAiA95PJIa3YgLMutWixJJK8Bg1gL8TbhP8MGaX7ZfXJu+ts2/f8sOM YcwuJ1t8DVF0DisPu34ODDTDKDDjnIYDOjRSUzDpp6hDV0fi2ATIT+ag7ZNUlPvfp3FZ OJyLIAQ8VMME1u5iY5NpdVeJHlOOenU9VjA/qkEiuJ9E45uoqChQsCPsUe5ZGu17FUhi qO3A== X-Gm-Message-State: AOJu0Yx/kRvyKXJlR32T8hRIVh6lySr+JjsDfn4a0DuFJOrcv8VOlOo7 gRLl5jT4y6W79WU1MPeYixF8cx3zMz4GR5q4SrY= X-Google-Smtp-Source: AGHT+IF/38k+mHYDsiCV9q5ja1BmiVsvVPQRkz7QNU8NMvABvumJfQv6Cb+Dkh3TgtDABWaEDoiMaQ== X-Received: by 2002:a05:6808:f8d:b0:3a7:3ea1:b5a0 with SMTP id o13-20020a0568080f8d00b003a73ea1b5a0mr14696027oiw.47.1691493459612; Tue, 08 Aug 2023 04:17:39 -0700 (PDT) Received: from [10.90.34.137] ([203.208.167.146]) by smtp.gmail.com with ESMTPSA id 30-20020a17090a005e00b0025023726fc4sm11179299pjb.26.2023.08.08.04.17.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Aug 2023 04:17:39 -0700 (PDT) Message-ID: <853af8fa-0cef-b00b-3fd6-9780a2008050@bytedance.com> Date: Tue, 8 Aug 2023 19:17:31 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: [RFC v1 4/5] maple_tree: avoid bulk alloc/free to use percpu array more To: Vlastimil Babka Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Joonsoo Kim , Pekka Enberg , David Rientjes , Christoph Lameter , "Liam R. Howlett" , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Matthew Wilcox References: <20230808095342.12637-7-vbabka@suse.cz> <20230808095342.12637-11-vbabka@suse.cz> From: Peng Zhang In-Reply-To: <20230808095342.12637-11-vbabka@suse.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2023/8/8 17:53, Vlastimil Babka 写道: > Using bulk alloc/free on a cache with percpu array should not be > necessary and the bulk alloc actually bypasses the array (the prefill > functionality currently relies on this). > > The simplest change is just to convert the respective maple tree > wrappers to do a loop of normal alloc/free. > --- > lib/maple_tree.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/lib/maple_tree.c b/lib/maple_tree.c > index 1196d0a17f03..7a8e7c467d7c 100644 > --- a/lib/maple_tree.c > +++ b/lib/maple_tree.c > @@ -161,12 +161,19 @@ static inline struct maple_node *mt_alloc_one(gfp_t gfp) > > static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes) > { > - return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes); > + int allocated = 0; > + for (size_t i = 0; i < size; i++) { > + nodes[i] = kmem_cache_alloc(maple_node_cache, gfp); > + if (nodes[i]) If the i-th allocation fails, node[i] will be NULL. This is wrong. We'd better guarantee that mt_alloc_bulk() allocates completely successfully, or returns 0. The following cases are not allowed: nodes: [addr1][addr2][NULL][addr3]. > + allocated++; > + } > + return allocated; > } > > static inline void mt_free_bulk(size_t size, void __rcu **nodes) > { > - kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes); > + for (size_t i = 0; i < size; i++) > + kmem_cache_free(maple_node_cache, nodes[i]); > } > > static void mt_free_rcu(struct rcu_head *head)