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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31A1DC433F5 for ; Wed, 19 Jan 2022 13:22:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 838E16B0071; Wed, 19 Jan 2022 08:22:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7E7966B0073; Wed, 19 Jan 2022 08:22:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6D7F66B0074; Wed, 19 Jan 2022 08:22:23 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0043.hostedemail.com [216.40.44.43]) by kanga.kvack.org (Postfix) with ESMTP id 5FD6F6B0071 for ; Wed, 19 Jan 2022 08:22:23 -0500 (EST) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 228398281DF5 for ; Wed, 19 Jan 2022 13:22:23 +0000 (UTC) X-FDA: 79047100566.31.AC3451E Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf26.hostedemail.com (Postfix) with ESMTP id 7DF30140008 for ; Wed, 19 Jan 2022 13:22:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=XdBwF/RjhbWIU5o6Jz7HpuQNLjSadEnmWI/i7GCW5y0=; b=Cc09zlkLM5/Ab6cb+M3cwSs7PG huGqk0aJjbCMfwx7cGINmtqiWpkOY2MZWDoKt5SA8m0jllV54qtTq+XMW167egJYN43cWA6wmB1kT NSiw6gsSlTYaYYCOytDuMJy4dFx/vs+lSzcFzo9SptNPM3xm07UEtjKPEEPZNEk8oivGNJkbVOLpd 5E4WhC0Wuj3mmjvZ3xxOdSBKLgCT1DGgCxproJPPwnGtPAjYjE7oVogDUTUmyoh8RSR3wa/r3oLCM BAkDt2EQRiO5AzaEt+RVfOvnIvPA1+sAN1KiGh40QWfqiVw95Gyi1Xn2ZGs2zJNxe5PnYpg//wkd6 sU6IJtWA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nAAua-00AsKQ-Da; Wed, 19 Jan 2022 13:22:04 +0000 Date: Wed, 19 Jan 2022 13:22:04 +0000 From: Matthew Wilcox To: Kefeng Wang Cc: Nicholas Piggin , Andrew Morton , Jonathan Corbet , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "H. Peter Anvin" , Ingo Molnar , Michael Ellerman , Paul Mackerras , Thomas Gleixner , Will Deacon Subject: Re: [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc default behavior Message-ID: References: <20211227145903.187152-1-wangkefeng.wang@huawei.com> <20211227145903.187152-2-wangkefeng.wang@huawei.com> <1642473992.qrnqczjfna.astroid@bobo.none> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 7DF30140008 X-Stat-Signature: z5qzcxnioi4kbuzxouyk9owj6cypnfft Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=Cc09zlkL; spf=none (imf26.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-HE-Tag: 1642598542-812456 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote: > Only parts of our products wants this feature,=C2=A0 we add some interf= aces which > only >=20 > alloc hugevmalloc for them, eg, > vmap_hugepage/vmalloc_hugepage/remap_vmalloc_hugepage_range.. >=20 > for our products, but it's not the choice of most products, also add > nohugevmalloc >=20 > for most products is expensive, so this is the reason for adding the pa= tch. >=20 > more config/cmdline are more flexible for test/products=EF=BC=8C But why do only some products want it? What goes wrong if all products enable it? Features should be auto-tuning, not relying on admins to understand them.