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=-6.9 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=no 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 9F067C388F9 for ; Wed, 11 Nov 2020 12:44:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBFE3206F1 for ; Wed, 11 Nov 2020 12:44:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="moyXqW+u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726376AbgKKMob (ORCPT ); Wed, 11 Nov 2020 07:44:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725859AbgKKMoa (ORCPT ); Wed, 11 Nov 2020 07:44:30 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 510DEC0613D1 for ; Wed, 11 Nov 2020 04:44:30 -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=6tLGLpk1EezWZwtwUC8VAuKl13a1TQOC6LFMQf+zejg=; b=moyXqW+upZidbk4p/nGEeku4bp EJ774Vg9KfGW5BWbjA7puJv9vzEPUgM6yJabRuKv+zO21a92tmwJeiVz+6b8kqUikxpBVGvn2O9gO oZXyq/Wma2LEfxxqfWZhz30doBdXoqwSB6lcNui8ejcLKdPUUSZN4r8yWG1BnFEzIfvMz9XuCsAFr kZ/HuMuJ2x+U1SNBw7l9BohJyCNAyCb+ORHQajutXr5CBIQINiXkvRutUMOxJC7Z1EmubZPiRIEnl y5g5kUkN9f+FWx3nbutTbublHeRIXnvsvKpsA5rk+fMG5MaeyQIK3exZsSzn9dz0XhDwZpjbkM7oc T32pGW7A==; 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 1kcpTl-0003SN-Hc; Wed, 11 Nov 2020 12:44:01 +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 079DB301324; Wed, 11 Nov 2020 13:43:58 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E8F912025CA2B; Wed, 11 Nov 2020 13:43:57 +0100 (CET) Date: Wed, 11 Nov 2020 13:43:57 +0100 From: Peter Zijlstra To: "Liang, Kan" Cc: Will Deacon , Michael Ellerman , mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, eranian@google.com, ak@linux.intel.com, dave.hansen@intel.com, kirill.shutemov@linux.intel.com, benh@kernel.crashing.org, paulus@samba.org, David Miller , vbabka@suse.cz, willy@infradead.org Subject: Re: [PATCH V9 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE Message-ID: <20201111124357.GS2651@hirez.programming.kicks-ass.net> References: <20201001135749.2804-2-kan.liang@linux.intel.com> <20201009090927.GQ2611@hirez.programming.kicks-ass.net> <877drz1qbc.fsf@mpe.ellerman.id.au> <20201012084829.GA1151@willie-the-truck> <20201013154615.GE2594@hirez.programming.kicks-ass.net> <20201013163449.GR2651@hirez.programming.kicks-ass.net> <8e88ba79-7c40-ea32-a7ed-bdc4fc04b2af@linux.intel.com> <20201111095750.GS2594@hirez.programming.kicks-ass.net> <20201111112246.GR2651@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201111112246.GR2651@hirez.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 11, 2020 at 12:22:46PM +0100, Peter Zijlstra wrote: > Trying to match the Code: to PageHuge as generate here makes this the > PageCompound() test burning, not even compound_head() going bad. > > must ponder more... Oooh.. does this help? --- kernel/events/core.c | 81 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 32 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index d2f3ca792936..3b42576c99f1 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7015,65 +7015,82 @@ static u64 perf_virt_to_phys(u64 virt) */ __weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr) { +#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL struct page *page; - pgd_t *pgd; - p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - - pgd = pgd_offset(mm, addr); - if (pgd_none(*pgd)) + pgd_t *pgdp, pgd; + p4d_t *p4dp, p4d; + pud_t *pudp, pud; + pmd_t *pmdp, pmd; + pte_t *ptep, pte; + + pgdp = pgd_offset(mm, addr); + pgd = READ_ONCE(*pgdp); + if (pgd_none(pgd)) return 0; - p4d = p4d_offset(pgd, addr); - if (!p4d_present(*p4d)) + p4dp = p4d_offset(&pgd, addr); + p4d = READ_ONCE(*p4dp); + if (!p4d_present(p4d)) return 0; - if (p4d_leaf(*p4d)) + if (p4d_leaf(p4d)) return 1ULL << P4D_SHIFT; - pud = pud_offset(p4d, addr); - if (!pud_present(*pud)) + pudp = pud_offset(&p4d, addr); + pud = READ_ONCE(*pudp); + if (!pud_present(pud)) return 0; - if (pud_leaf(*pud)) { + if (pud_leaf(pud)) { #ifdef pud_page - page = pud_page(*pud); - if (PageHuge(page)) - return page_size(compound_head(page)); + if (!pud_devmap(pud)) { + page = pud_page(pud); + if (PageHuge(page)) + return page_size(compound_head(page)); + } #endif return 1ULL << PUD_SHIFT; } - pmd = pmd_offset(pud, addr); - if (!pmd_present(*pmd)) + pmdp = pmd_offset(&pud, addr); + pmd = READ_ONCE(*pmdp); + if (!pmd_present(pmd)) return 0; - if (pmd_leaf(*pmd)) { + if (pmd_leaf(pmd)) { #ifdef pmd_page - page = pmd_page(*pmd); - if (PageHuge(page)) - return page_size(compound_head(page)); + if (!pmd_devmap(pmd)) { + page = pmd_page(pmd); + if (PageHuge(page)) + return page_size(compound_head(page)); + } #endif return 1ULL << PMD_SHIFT; } - pte = pte_offset_map(pmd, addr); - if (!pte_present(*pte)) { - pte_unmap(pte); + ptep = pte_offset_map(&pmd, addr); + pte = READ_ONCE(*ptep); // gup_get_pte() + if (!pte_present(pte)) { + pte_unmap(ptep); return 0; } - page = pte_page(*pte); - if (PageHuge(page)) { - u64 size = page_size(compound_head(page)); - pte_unmap(pte); - return size; + if (!pte_devmap(pte) && !pte_special(pte)) { + page = pte_page(pte); + if (PageHuge(page)) { + u64 size = page_size(compound_head(page)); + pte_unmap(ptep); + return size; + } } - pte_unmap(pte); + pte_unmap(ptep); return PAGE_SIZE; + +#else /* CONFIG_ARCH_HAS_PTE_SPECIAL */ + + return 0; +#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */ } #else