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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 06DDFC282D8 for ; Fri, 1 Feb 2019 12:44:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA48B2080D for ; Fri, 1 Feb 2019 12:44:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="QM+Clht4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730171AbfBAMoE (ORCPT ); Fri, 1 Feb 2019 07:44:04 -0500 Received: from merlin.infradead.org ([205.233.59.134]:44790 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726450AbfBAMoD (ORCPT ); Fri, 1 Feb 2019 07:44:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=SbRZEa6XeyV6JGwyjlS9B0Du/M+eR1tynCsuokCT2Es=; b=QM+Clht4lIXp/uAVedTr2O24Z tB1CFgE+QfFelgR4wlbHJ8JTvZq4SgLeDG9Das/F14MoKnfxhJF4nkd2ZDYhWWmb6Y8Nj8wXJhMUn wlR8+iFGSxhjZ/8+kpYoAOOUsM7JxP6F1YfGzJ5rPUElKoWFGUNzYx9Euejs2I2LTFRBAmcy5Vbcl JdOJ0zg35bfX94cLzVAt6zF1nxFlJFDzaqNkQNV9lBimTO3bcOl1jrVMkk9Y0miPRuvdNB6UfkFNW dvcQn2XcTjGlrkgVLvBotEesnPazyfHfoIux+6Vx6GGsyBW7Ute4XzwtbIi+kUL210JOas//r6nky fk33ybPrg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gpYAg-00007w-2C; Fri, 01 Feb 2019 12:43:50 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8D8172849125B; Fri, 1 Feb 2019 13:43:48 +0100 (CET) Date: Fri, 1 Feb 2019 13:43:48 +0100 From: Peter Zijlstra To: "Kirill A. Shutemov" Cc: kan.liang@linux.intel.com, acme@kernel.org, tglx@linutronix.de, mingo@redhat.com, linux-kernel@vger.kernel.org, eranian@google.com, jolsa@redhat.com, namhyung@kernel.org, ak@linux.intel.com, luto@amacapital.net, Vlastimil Babka , Will Deacon Subject: Re: [PATCH V4 01/13] perf/core, x86: Add PERF_SAMPLE_DATA_PAGE_SIZE Message-ID: <20190201124348.GC31534@hirez.programming.kicks-ass.net> References: <1548966486-49963-1-git-send-email-kan.liang@linux.intel.com> <20190201092240.GB31498@hirez.programming.kicks-ass.net> <20190201100358.GD31552@hirez.programming.kicks-ass.net> <20190201103600.uflrwzgwj2tadhey@kshutemo-mobl1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190201103600.uflrwzgwj2tadhey@kshutemo-mobl1> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 01, 2019 at 01:36:00PM +0300, Kirill A. Shutemov wrote: > On Fri, Feb 01, 2019 at 11:03:58AM +0100, Peter Zijlstra wrote: > > Will just mentioned a lovely feature where some archs have multi entry > > large pages. > > > > Possible something like: > > > > if (pud_large(*pud)) { > > struct page *page = pud_page(*pud); > > int order = PUD_SHIFT; > > > > if (PageHuge(page)) { > > page = compound_head(page); > > order += compound_order(page); > > } > > > > return 1ULL << order; > > } > > > > works correctly. > > For more fun: some compound pages can be mapped withe page table entries > not matching it's compound size, i.e. 2M pages mapped with PTE. Surely not for PageHuge() ?! I thought the point of hugetlbfs was to guarantee page granularity. How is the below? static u64 __perf_get_page_size(struct mm_struct *mm, unsigned long addr) { pgd_t *pgd; p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; pgd = pgd_offset(mm, addr); if (pgd_none(*pgd)) return 0; p4d = p4d_offset(pgd, addr); if (!p4d_present(*p4d)) return 0; if (p4d_large(*p4d)) { struct page *page = p4d_page(*p4d); int shift = P4D_SHIFT; if (PageHuge(page)) { page = compound_head(page); shift = PAGE_SHIFT + compound_order(page); } return 1ULL << shift; } if (!p4d_present(*p4d)) return 0; pud = pud_offset(p4d, addr); if (!pud_present(*pud)) return 0; if (pud_large(*pud)) { struct page *page = pud_page(*pud); int shift = P4D_SHIFT; if (PageHuge(page)) { page = compound_head(page); shift = PAGE_SHIFT + compound_order(page); } return 1ULL << shift; } pmd = pmd_offset(pud, addr); if (!pmd_present(*pmd)) return 0; if (pmd_large(*pmd)) { struct page *page = pud_page(*pud); int shift = P4D_SHIFT; if (PageHuge(page)) { page = compound_head(page); shift = PAGE_SHIFT + compound_order(page); } return 1ULL << shift; } pte = pte_offset_map(pmd, addr); if (!pte_present(*pte)) { pte_unmap(pte); return 0; } pte_unmap(pte); return PAGE_SIZE; }