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 X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39F38C433ED for ; Tue, 11 May 2021 02:59:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18C9C61409 for ; Tue, 11 May 2021 02:59:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230134AbhEKDBA (ORCPT ); Mon, 10 May 2021 23:01:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229586AbhEKDA7 (ORCPT ); Mon, 10 May 2021 23:00:59 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEB8DC061574 for ; Mon, 10 May 2021 19:59:52 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id s20so10100217plr.13 for ; Mon, 10 May 2021 19:59:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=FSJUUz/f4tLbua2BU6pbEJOw8M2Tk15/Iao3DwjhR3M=; b=NBm9MvSthgsH3p1QPhZiv8ZyGUJ2hJK1wOu7fHnwpCfIJ3213hxEWmYNe2DLxpac94 A8WPX/Ekoh6FiHJz/wWXoQ+UguDT0FPxYjBocobFrnaZKWO1IisrLbtU8l2Iams6idy8 xfJGGo24Il6Yv/SRmYZ/NRN7irli9FSvzTKxYtfFZFvAupovGXlMlqosjFWZKweHAWFU k3DhacQ6nTMpV8dDSw6hB2FP+9jjP0eRhiMVzIMFYw6DokLVoadybe+oeI0Fs6ntHJyh g9rr0RrWU9vPx3Ksn4EuBKBo5cgf8hRselzAZMHWuEuCwRtf5fM8NF4zmcEiP7psiw1+ aXjw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=FSJUUz/f4tLbua2BU6pbEJOw8M2Tk15/Iao3DwjhR3M=; b=glKI0d+J+ilOMy3wR7P0SFUgmBzuwSQZ6xUZNtx9zakgyUiUaj+1yl+v5MkfXvFIVn 8+OMNma+15PsgvVoX82RUWZ4c5yhQ81GSpAezl+F5ERULT0exf08gPZm/+QH0TGriAc3 HMxckM5OaCAXByTZC0+TXqsAzEr0Uy0Z8EnsFrWeD0IC8+Qhi1RSUnwl9UVozUFcikVw zbNeMQbXkPlVjs+zOmQ2SIvMuwwbrumpJv41sYe/ndscabJ2BY4BJ3PfHNXfAiBfxm3g EFztmrcJEAn3hrswwVIpLAMpOzchoe+hRBJej8v16K6hH/jg6b/lUqupumlP0+WU4RQ+ yDGw== X-Gm-Message-State: AOAM533/E1pt6JUfRj9rPOIdp+hMCWv6oROrxZFsd2X1NPys0tICuKNK 6wimVrn2BtcBbD3Ar8ucZBM= X-Google-Smtp-Source: ABdhPJxqEe604ctRXMNgtR96MG4nb+LP029JD7OzOHFnTeNsp0Xl/1M1BX2JpsYEujKKuQxtu/WaDQ== X-Received: by 2002:a17:90a:7a85:: with SMTP id q5mr2513894pjf.49.1620701991901; Mon, 10 May 2021 19:59:51 -0700 (PDT) Received: from hyeyoo ([183.99.11.150]) by smtp.gmail.com with ESMTPSA id 132sm12441756pfw.38.2021.05.10.19.59.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 May 2021 19:59:51 -0700 (PDT) Date: Tue, 11 May 2021 11:59:46 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Vlastimil Babka Cc: Matthew Wilcox , cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] mm: change run-time assertion in kmalloc_index() to compile-time Message-ID: <20210511025946.GA98904@hyeyoo> References: <20210508221328.7338-1-42.hyeyoo@gmail.com> <20210510135857.GA3594@hyeyoo> <9d0ffe49-a2e2-6c81-377b-4c8d2147dff8@suse.cz> <20210510150230.GA74915@hyeyoo> <90591d7e-41e4-9ae5-54ae-ded467c498cf@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <90591d7e-41e4-9ae5-54ae-ded467c498cf@suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >From c2b8fc4144f2c44b0ac5957a06207c385cc94d15 Mon Sep 17 00:00:00 2001 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> Date: Tue, 11 May 2021 11:53:23 +0900 Subject: [PATCH] mm, slub: change run-time assertion in kmalloc_index() to compile-time currently when size is not supported by kmalloc_index, compiler will generate a run-time BUG() while compile-time error is also possible, and better. so changed BUG to BUILD_BUG_ON_MSG to make compile-time check possible. also removed code that allocates more than 32MB because current implementation supports only up to 32MB. Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> --- include/linux/slab.h | 7 +++++-- mm/slab_common.c | 7 +++---- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index 6d454886bcaf..df1937309df2 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -345,6 +345,9 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) * 1 = 65 .. 96 bytes * 2 = 129 .. 192 bytes * n = 2^(n-1)+1 .. 2^n + * + * Note: there's no need to optimize kmalloc_index because it's evaluated + * in compile-time. */ static __always_inline unsigned int kmalloc_index(size_t size) { @@ -381,8 +384,8 @@ static __always_inline unsigned int kmalloc_index(size_t size) if (size <= 8 * 1024 * 1024) return 23; if (size <= 16 * 1024 * 1024) return 24; if (size <= 32 * 1024 * 1024) return 25; - if (size <= 64 * 1024 * 1024) return 26; - BUG(); + + BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); /* Will never be reached. Needed because the compiler may complain */ return -1; diff --git a/mm/slab_common.c b/mm/slab_common.c index fe8b68482670..97664bbe8147 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1192,8 +1192,8 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) /* * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. - * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is - * kmalloc-67108864. + * kmalloc_index() supports up to 2^25=32MB, so the final entry of the table is + * kmalloc-32M. */ const struct kmalloc_info_struct kmalloc_info[] __initconst = { INIT_KMALLOC_INFO(0, 0), @@ -1221,8 +1221,7 @@ const struct kmalloc_info_struct kmalloc_info[] __initconst = { INIT_KMALLOC_INFO(4194304, 4M), INIT_KMALLOC_INFO(8388608, 8M), INIT_KMALLOC_INFO(16777216, 16M), - INIT_KMALLOC_INFO(33554432, 32M), - INIT_KMALLOC_INFO(67108864, 64M) + INIT_KMALLOC_INFO(33554432, 32M) }; /* -- 2.25.1