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 57769C7EE23 for ; Tue, 6 Jun 2023 02:41:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233954AbjFFClm (ORCPT ); Mon, 5 Jun 2023 22:41:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234246AbjFFClj (ORCPT ); Mon, 5 Jun 2023 22:41:39 -0400 Received: from mail-yw1-x1131.google.com (mail-yw1-x1131.google.com [IPv6:2607:f8b0:4864:20::1131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA984122 for ; Mon, 5 Jun 2023 19:41:34 -0700 (PDT) Received: by mail-yw1-x1131.google.com with SMTP id 00721157ae682-565f1145dc8so60533197b3.1 for ; Mon, 05 Jun 2023 19:41:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686019294; x=1688611294; h=mime-version:references:message-id:in-reply-to:subject:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=/OY+878V1FQUEQIL1kvZEgzbdoaux9eczVlkSaD+I/Q=; b=TJRJ5MwMTAsRDF6xptr1GnPQQGOWkOSr9nqwm+2T4bFB2fnQYtY0MAFfIXuzj/facS Bq/AblFVzb2VZBFBMj8m3Aun+sKDDxRnlWdi1tqEbP4V9Msk9UEhvNN8fBw01hPkZcqh aCefalnixHirL+Sbfzojc2ubXX/dqN6pry0icsNDpadK1LL0wBIg+wQhdtsURMQSVYB+ TelDBkzPL0Afw+kOv2kW7OuzpJz9ocapwkhr955CRcQVRBE5V10YpVkKlu/GtSMgtxwY 9FBEKhQ3iuBivA6Md2gtnn8rrCeaXIdHnTJ7irl+szonbwlw673TUrUDgluT9NC8wPbt WpRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686019294; x=1688611294; h=mime-version:references:message-id:in-reply-to:subject:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=/OY+878V1FQUEQIL1kvZEgzbdoaux9eczVlkSaD+I/Q=; b=MK1gkgPnOn+uxsi28oGYqNtd4OFszk9UbrpHVBueCXydpyf/QfATFD1luboouc2RYy v7y0CdmtcyK6r+wCYMGXBCFHpoHoO7q6Tgi/EBQ6eqkMXbNRUuKg/X/m0HPgJ0crZarH LSH/vAwtuzu73FgJ8y/AbLPWIT3MvMHysDNfZZiB9Yn2d6+VROHjQrn1x7uCTPcZDqlC HCB9nhG/SlfKEvPuKXrg90vCKNKfCoEgnQP+28ladd7ej/GUqRWrL9/txxYG65qdxHwy JdbSzOPP09v7TNkFv/pE/I61lkh7Gyhm+hznzjIdj5o6L3OPPAonCbYuIJyjbWUrJo5O 00Sw== X-Gm-Message-State: AC+VfDxuaOf4B39/Muls2AKGLN7erEZxkZbiAvsbV3CSqjsv6hWuF7J9 Ms7hb/UKtqakxkjTl5LixAO7RQ== X-Google-Smtp-Source: ACHHUZ4+H1RDAiuTWrigMwLJw3JR7kzzMdIFJ9hsdOOC0dyodzvNJbwlgT4q0yPmIIHx50HRHgPAOQ== X-Received: by 2002:a0d:f943:0:b0:552:96e0:ccd0 with SMTP id j64-20020a0df943000000b0055296e0ccd0mr620675ywf.16.1686019293978; Mon, 05 Jun 2023 19:41:33 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id g67-20020a816b46000000b00559ec10f245sm3706391ywc.103.2023.06.05.19.41.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jun 2023 19:41:33 -0700 (PDT) Date: Mon, 5 Jun 2023 19:41:22 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: "Liam R. Howlett" , Peng Zhang , "Yin, Fengwei" , maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Liu, Yujie" , Andrew Morton Subject: Re: [PATCH 00/14] Reduce preallocations for maple tree In-Reply-To: <20230605140344.66pwpdg5zgb6rfa7@revolver> Message-ID: <9f4c10bb-ee7c-cd41-f1b9-c1a7a1a562fd@google.com> References: <20230601021605.2823123-1-Liam.Howlett@oracle.com> <7a5dc9ce-b58f-e1b3-db1a-d00a8a556ae5@intel.com> <4fb5f66d-c8c2-f857-7461-b974154dbc2b@bytedance.com> <20230605140344.66pwpdg5zgb6rfa7@revolver> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 5 Jun 2023, Liam R. Howlett wrote: > > You mean "mm: update validate_mm() to use vma iterator" here I guess. I > have it as a different commit id in my branch. > > I 'restored' some of the checking because I was able to work around not > having the mt_dump() definition with the vma iterator. I'm now > wondering how wide spread CONFIG_DEBUG_VM is used and if I should not > have added these extra checks. Most CONFIG_DEBUG_VM checks are quite cheap, mostly VM_BUG_ONs for easily checked conditions. If validate_mm() is still the kind of thing it used to be, checking through every vma on every mmap operation, please don't bring that into CONFIG_DEBUG_VM - it distorts performance too much, so always used to be under a separate CONFIG_DEBUG_VM_RB instead. Hugh