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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 3FE1EC64E90 for ; Thu, 26 Nov 2020 10:47:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B394E2158C for ; Thu, 26 Nov 2020 10:47:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="X3cXyvr1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388371AbgKZKrj (ORCPT ); Thu, 26 Nov 2020 05:47:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388340AbgKZKri (ORCPT ); Thu, 26 Nov 2020 05:47:38 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEDC0C0613D4; Thu, 26 Nov 2020 02:47:38 -0800 (PST) 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=tFBEb0BLu3uXogjw3SOLqhrulKz6jh3zxahm8XIOiP8=; b=X3cXyvr1KiNTPPNYsE55p34qzs 01WR57/NTCJJBTLnooSCiqxRLfe1NoFr12FKiB6sIEBBSutg9ejvt0PVkeecAF+mpv6dTf8ALS0Gm xhqbpCHFBeyIrf+sFcr5qLhcRmKH4/FE0Pt3zYF5jFf46D9MsXl8GMUOivcOmSz7vK+xfdAkyV351 jzDDCgoug6jn/+HFsM1y/JKSSLVp9DlLQ8ZRbbpJ9c6bp/kBfbJCLFmcooHmQW9b98d3DJDJ2/FR0 xeXgp6zkPj+bioLqm25WdK36TJtI5sB9sBZ3lALxjkdNEuHxVS3oL6SFnqB+2FlF9dqVtYpLh7738 LsYFbjzA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kiEnd-0003Eg-Ub; Thu, 26 Nov 2020 10:46:55 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 38B21306DD8; Thu, 26 Nov 2020 11:46:51 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 137AC20162619; Thu, 26 Nov 2020 11:46:51 +0100 (CET) Date: Thu, 26 Nov 2020 11:46:51 +0100 From: Peter Zijlstra To: Christophe Leroy Cc: kan.liang@linux.intel.com, mingo@kernel.org, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, eranian@google.com, npiggin@gmail.com, linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au, will@kernel.org, willy@infradead.org, aneesh.kumar@linux.ibm.com, sparclinux@vger.kernel.org, davem@davemloft.net, catalin.marinas@arm.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, ak@linux.intel.com, dave.hansen@intel.com, kirill.shutemov@linux.intel.com Subject: Re: [PATCH 0/5] perf/mm: Fix PERF_SAMPLE_*_PAGE_SIZE Message-ID: <20201126104651.GG3092@hirez.programming.kicks-ass.net> References: <20201113111901.743573013@infradead.org> <16ad8cab-08e2-27a7-6803-baadc6b8721b@csgroup.eu> <2a32b00b-2214-3283-58e0-9cb0ff4bd728@csgroup.eu> <20201120122004.GG3021@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201120122004.GG3021@hirez.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Fri, Nov 20, 2020 at 01:20:04PM +0100, Peter Zijlstra wrote: > > > I can help with powerpc 8xx. It is a 32 bits powerpc. The PGD has 1024 > > > entries, that means each entry maps 4M. > > > > > > Page sizes are 4k, 16k, 512k and 8M. > > > > > > For the 8M pages we use hugepd with a single entry. The two related PGD > > > entries point to the same hugepd. > > > > > > For the other sizes, they are in standard page tables. 16k pages appear > > > 4 times in the page table. 512k entries appear 128 times in the page > > > table. > > > > > > When the PGD entry has _PMD_PAGE_8M bits, the PMD entry points to a > > > hugepd with holds the single 8M entry. > > > > > > In the PTE, we have two bits: _PAGE_SPS and _PAGE_HUGE > > > > > > _PAGE_HUGE means it is a 512k page > > > _PAGE_SPS means it is not a 4k page > > > > > > The kernel can by build either with 4k pages as standard page size, or > > > 16k pages. It doesn't change the page table layout though. > > > > > > Hope this is clear. Now I don't really know to wire that up to your series. Does the below accurately reflect things? Let me go find a suitable cross-compiler .. diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h index 1581204467e1..fcc48d590d88 100644 --- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h @@ -135,6 +135,29 @@ static inline pte_t pte_mkhuge(pte_t pte) } #define pte_mkhuge pte_mkhuge + +static inline unsigned long pgd_leaf_size(pgd_t pgd) +{ + if (pgd_val(pgd) & _PMD_PAGE_8M) + return SZ_8M; + return SZ_4M; +} + +#define pgd_leaf_size pgd_leaf_size + +static inline unsigned long pte_leaf_size(pte_t pte) +{ + pte_basic_t val = pte_val(pte); + + if (val & _PAGE_HUGE) + return SZ_512K; + if (val & _PAGE_SPS) + return SZ_16K; + return SZ_4K; +} + +#define pte_leaf_size pte_leaf_size + #endif #endif /* __KERNEL__ */