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 806EAC61D97 for ; Thu, 23 Nov 2023 15:48:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0FE618D004F; Thu, 23 Nov 2023 10:48:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 087448D0002; Thu, 23 Nov 2023 10:48:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E68F08D004F; Thu, 23 Nov 2023 10:48:01 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id D3CE08D0002 for ; Thu, 23 Nov 2023 10:48:01 -0500 (EST) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id A642D160B3C for ; Thu, 23 Nov 2023 15:48:01 +0000 (UTC) X-FDA: 81489649962.10.6528C74 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf24.hostedemail.com (Postfix) with ESMTP id 05BD218000E for ; Thu, 23 Nov 2023 15:47:59 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=vLpbgGiz; dmarc=none; spf=none (imf24.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1700754480; a=rsa-sha256; cv=none; b=X5wEgNEscnmfdra0jKbHEabrJe5cdhXzkzMcMsOna6KvfpWZsw4LvMngJza8JoOJ7tJU0H GhoHDRL0mkGhnWW6cdkbL13pk0L9yaJbmNw/INiX2FvlbOM3bbtrEcENQN63ubMAgKc/US T42Bv32OPKeKX2pRx+rXwQLgaAuuSDY= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=vLpbgGiz; dmarc=none; spf=none (imf24.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1700754480; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=vasH22+ZqE7NawyIR92P5uPhDSRcq1ysNxbjToJ1LBY=; b=qOBtYb3VgiIJWqKkR640i8fuZN8oHaouPYWaDBohkGu+8uYCKopGt8oF97LMRyaa3qXDDM c0UKr7rTvKLCVnnkCBFtYhs6N1a4TuCC422NqF3cq+6OdjfZaJSI8nc0lnQ2Sj1QEqWqf5 +Yz9qHgslROJZrwu7PnLMHpa7+9LFUQ= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=vasH22+ZqE7NawyIR92P5uPhDSRcq1ysNxbjToJ1LBY=; b=vLpbgGizfUkL6qUgpsivl4JAm/ l8J8tNyrQHt5ij+7+mH22jvJHwKDnm15G+Y8yMTDvxK5gRlnADcaWJ0gGwXnEL+X6/fGctU+gIkgH i7e0bTPjn5mArHPGmVnZ3Sd4irNBwcAJX3hcvaGLJPXbWqYn15n3uPyDZxtwkLGiuzrZBSL0W3h7g 0NnaVmbnZK083gVv5tpkKKqa2NiGaBEqg1aGsZitgcpovI9OR2AvH5HpmcbdwkXTFME1UrDr2MgzP GZEnBpDtPaOAgDKKUAZp8G4YTEUeZWMFnI74HVPypN/duW75NVuUCoPbRlM89yKGH7bN101Tg5qlt qowOlYxw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1r6Bvh-007gJ1-SR; Thu, 23 Nov 2023 15:47:49 +0000 Date: Thu, 23 Nov 2023 15:47:49 +0000 From: Matthew Wilcox To: Christoph Hellwig Cc: Peter Xu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrea Arcangeli , James Houghton , Lorenzo Stoakes , David Hildenbrand , Vlastimil Babka , John Hubbard , Yang Shi , Rik van Riel , Hugh Dickins , Jason Gunthorpe , Axel Rasmussen , "Kirill A . Shutemov" , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Mike Rapoport , Mike Kravetz Subject: Re: [PATCH RFC 06/12] mm/gup: Drop folio_fast_pin_allowed() in hugepd processing Message-ID: References: <20231116012908.392077-1-peterx@redhat.com> <20231116012908.392077-7-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 05BD218000E X-Stat-Signature: 8xr6zuo8kd7ef3j7n35umymudje3pgpy X-HE-Tag: 1700754479-95935 X-HE-Meta: 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 kF64NNu/ SLFZzelcASIuMhhFRR2g4TxRFhDwVRFvo+vinT+Fqfza5R1mGMz2Klzdfz8eAG9urMYcW9aPa2aP6Zt9zjlwDVcEPZ3xXsSUnq3Sf6/7lYh3ZohjiaNRXIYg+bQ8aVR6t0bBjnG9aHXmsrDWup8gWekmN9jBQZLgy09onbGOVzpHFQdZ0BwO+cnLKpg== 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: List-Subscribe: List-Unsubscribe: On Wed, Nov 22, 2023 at 12:00:24AM -0800, Christoph Hellwig wrote: > > The other option is I can always add a comment above gup_huge_pd() > > explaining this special bit, so that when someone is adding hugepd support > > to file large folios we'll hopefully not forget it? But then that > > generalization work will only happen when the code will be needed. > > If dropping the check is the right thing for now (and I think the ppc > maintainers and willy as the large folio guy might have a more useful > opinions than I do), leaving a comment in would be very useful. It looks like ARM (in the person of Ryan) are going to add support for something equivalent to hugepd. Insofar as I understand hugepd, anyway. I've done my best to set up the generic code so that the arch code can use whatever size TLB entries it supports. I haven't been looking to the hugetlb code as a reference for it, since it can assume natural alignment and generic THP/large folio must be able to handle arbitrary alignment. If powerpc want to join in on the fun, they're more than welcome, but I get the feeling that investment in Linux-on-PPC is somewhat smaller than Linux-on-ARM these days. Even if we restrict that to the server space.