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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,URIBL_BLOCKED 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 A1466C43460 for ; Fri, 30 Apr 2021 05:57:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 802E361476 for ; Fri, 30 Apr 2021 05:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230215AbhD3F6B (ORCPT ); Fri, 30 Apr 2021 01:58:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:51026 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230182AbhD3F6B (ORCPT ); Fri, 30 Apr 2021 01:58:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2698061463; Fri, 30 Apr 2021 05:57:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762233; bh=GoucAA0pAe1fRH71QfwoLd2aEz+v2XpZqE+UWw01jqo=; h=Date:From:To:Subject:In-Reply-To:From; b=n6rDhMe/k6voqKNqSiXVJXe5YoSTQ2JlB0Q/gBypC4UFRDB6fhIYMMCzlw803yxlh EGc3sZfe6aeC3/AZ36syb26q4hR0KQE2rgwg9w/BWE8VGUIG9O2kCL4v27qfbwaqwL CSQ0j09S65XocwhNaKfU1MwPVrFCRWLreRRg3wLs= Date: Thu, 29 Apr 2021 22:57:12 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bp@alien8.de, dave.hansen@linux.intel.com, david@redhat.com, hpa@zytor.com, linux-mm@kvack.org, luto@kernel.org, mhocko@kernel.org, mingo@redhat.com, mm-commits@vger.kernel.org, osalvador@suse.de, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, ziy@nvidia.com Subject: [patch 079/178] x86/vmemmap: drop handling of 4K unaligned vmemmap range Message-ID: <20210430055712.Gw2Z6OFIS%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Oscar Salvador Subject: x86/vmemmap: drop handling of 4K unaligned vmemmap range Patch series "Cleanup and fixups for vmemmap handling", v6. This series contains cleanups to remove dead code that handles unaligned cases for 4K and 1GB pages (patch#1 and patch#2) when removing the vemmmap range, and a fix (patch#3) to handle the case when two vmemmap ranges intersect the same PMD. This patch (of 4): remove_pte_table() is prepared to handle the case where either the start or the end of the range is not PAGE aligned. This cannot actually happen: __populate_section_memmap enforces the range to be PMD aligned, so as long as the size of the struct page remains multiple of 8, the vmemmap range will be aligned to PAGE_SIZE. Drop the dead code and place a VM_BUG_ON in vmemmap_{populate,free} to catch nasty cases. Note that the VM_BUG_ON is placed in there because vmemmap_{populate,free= } is the gate of all removing and freeing page tables logic. Link: https://lkml.kernel.org/r/20210309214050.4674-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20210309214050.4674-2-osalvador@suse.de Signed-off-by: Oscar Salvador Suggested-by: David Hildenbrand Reviewed-by: David Hildenbrand Acked-by: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H . Peter Anvin" Cc: Michal Hocko Cc: Zi Yan Signed-off-by: Andrew Morton --- arch/x86/mm/init_64.c | 50 +++++++++++----------------------------- 1 file changed, 14 insertions(+), 36 deletions(-) --- a/arch/x86/mm/init_64.c~x86-vmemmap-drop-handling-of-4k-unaligned-vmemmap-range +++ a/arch/x86/mm/init_64.c @@ -962,7 +962,6 @@ remove_pte_table(pte_t *pte_start, unsig { unsigned long next, pages = 0; pte_t *pte; - void *page_addr; phys_addr_t phys_addr; pte = pte_start + pte_index(addr); @@ -983,42 +982,15 @@ remove_pte_table(pte_t *pte_start, unsig if (phys_addr < (phys_addr_t)0x40000000) return; - if (PAGE_ALIGNED(addr) && PAGE_ALIGNED(next)) { - /* - * Do not free direct mapping pages since they were - * freed when offlining, or simply not in use. - */ - if (!direct) - free_pagetable(pte_page(*pte), 0); - - spin_lock(&init_mm.page_table_lock); - pte_clear(&init_mm, addr, pte); - spin_unlock(&init_mm.page_table_lock); - - /* For non-direct mapping, pages means nothing. */ - pages++; - } else { - /* - * If we are here, we are freeing vmemmap pages since - * direct mapped memory ranges to be freed are aligned. - * - * If we are not removing the whole page, it means - * other page structs in this page are being used and - * we cannot remove them. So fill the unused page_structs - * with 0xFD, and remove the page when it is wholly - * filled with 0xFD. - */ - memset((void *)addr, PAGE_INUSE, next - addr); - - page_addr = page_address(pte_page(*pte)); - if (!memchr_inv(page_addr, PAGE_INUSE, PAGE_SIZE)) { - free_pagetable(pte_page(*pte), 0); + if (!direct) + free_pagetable(pte_page(*pte), 0); - spin_lock(&init_mm.page_table_lock); - pte_clear(&init_mm, addr, pte); - spin_unlock(&init_mm.page_table_lock); - } - } + spin_lock(&init_mm.page_table_lock); + pte_clear(&init_mm, addr, pte); + spin_unlock(&init_mm.page_table_lock); + + /* For non-direct mapping, pages means nothing. */ + pages++; } /* Call free_pte_table() in remove_pmd_table(). */ @@ -1197,6 +1169,9 @@ remove_pagetable(unsigned long start, un void __ref vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap) { + VM_BUG_ON(!IS_ALIGNED(start, PAGE_SIZE)); + VM_BUG_ON(!IS_ALIGNED(end, PAGE_SIZE)); + remove_pagetable(start, end, false, altmap); } @@ -1556,6 +1531,9 @@ int __meminit vmemmap_populate(unsigned { int err; + VM_BUG_ON(!IS_ALIGNED(start, PAGE_SIZE)); + VM_BUG_ON(!IS_ALIGNED(end, PAGE_SIZE)); + if (end - start < PAGES_PER_SECTION * sizeof(struct page)) err = vmemmap_populate_basepages(start, end, node, NULL); else if (boot_cpu_has(X86_FEATURE_PSE)) _