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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7B1CDC433E0 for ; Fri, 7 Aug 2020 06:23:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51A9622C9F for ; Fri, 7 Aug 2020 06:23:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596781423; bh=pKp42157LVeOknNBd7LiaFPgBvnjnDzy1vxKfs6KgOI=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=LviI5XKOuFmsP7muqACI4Z3A1rLKe7HmM+sdK6Cuogg6gR83tHDVzeP1ndHd5j9dY 6MZCWu4XU15XSmpHnB747A+H1mbHu/2WtPS3f5FizEUmtBRqbX1IY+2MdlJHYYQR6f MSdlCX7EVwvIDKJd2yV7fQeR0K43xwf4ydYssjrw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725845AbgHGGXm (ORCPT ); Fri, 7 Aug 2020 02:23:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:60762 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726249AbgHGGXm (ORCPT ); Fri, 7 Aug 2020 02:23:42 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0B714221E5; Fri, 7 Aug 2020 06:23:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596781421; bh=pKp42157LVeOknNBd7LiaFPgBvnjnDzy1vxKfs6KgOI=; h=Date:From:To:Subject:In-Reply-To:From; b=AKEk6zTGJY6nCeZ95yvOiLyta2cG6YTWT7oPin0yY9Eo5/ToDzsoF1jiaFpCRn7YJ Hri51jXjWPFKneplf3XkLt/aBP30ZgzJ4zbRE0RxwCzhxF+V4VxPgxjqrN8ZIlmYRt lq1QDT+XZiaFvj1U2RSCGPnaPy5iaMSZXDM4XABY= Date: Thu, 06 Aug 2020 23:23:40 -0700 From: Andrew Morton To: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, anshuman.khandual@arm.com, digetx@gmail.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, peterx@redhat.com, richard.weiyang@linux.alibaba.com, sean.j.christopherson@intel.com, thellstrom@vmware.com, thomas_os@shipmail.org, torvalds@linux-foundation.org, vbabka@suse.cz, willy@infradead.org, yang.shi@linux.alibaba.com Subject: [patch 114/163] mm/mremap: it is sure to have enough space when extent meets requirement Message-ID: <20200807062340.n7YybPMLI%akpm@linux-foundation.org> In-Reply-To: <20200806231643.a2711a608dd0f18bff2caf2b@linux-foundation.org> User-Agent: s-nail v14.8.16 Sender: mm-commits-owner@vger.kernel.org Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Wei Yang Subject: mm/mremap: it is sure to have enough space when extent meets requirement Patch series "mm/mremap: cleanup move_page_tables() a little", v5. move_page_tables() tries to move page table by PMD or PTE. The root reason is if it tries to move PMD, both old and new range should be PMD aligned. But current code calculate old range and new range separately. This leads to some redundant check and calculation. This cleanup tries to consolidate the range check in one place to reduce some extra range handling. This patch (of 3): old_end is passed to these two functions to check whether there is enough space to do the move, while this check is done before invoking these functions. These two functions only would be invoked when extent meets the requirement and there is one check before invoking these functions: if (extent > old_end - old_addr) extent = old_end - old_addr; This implies (old_end - old_addr) won't fail the check in these two functions. Link: http://lkml.kernel.org/r/20200710092835.56368-1-richard.weiyang@linux.alibaba.com Link: http://lkml.kernel.org/r/20200710092835.56368-2-richard.weiyang@linux.alibaba.com Link: http://lkml.kernel.org/r/20200708095028.41706-1-richard.weiyang@linux.alibaba.com Link: http://lkml.kernel.org/r/20200708095028.41706-2-richard.weiyang@linux.alibaba.com Signed-off-by: Wei Yang Tested-by: Dmitry Osipenko Acked-by: Kirill A. Shutemov Cc: Vlastimil Babka Cc: Yang Shi Cc: Thomas Hellstrom (VMware) Cc: Anshuman Khandual Cc: Sean Christopherson Cc: Wei Yang Cc: Peter Xu Cc: Aneesh Kumar K.V Cc: Matthew Wilcox Cc: Thomas Hellstrom Signed-off-by: Andrew Morton --- include/linux/huge_mm.h | 2 +- mm/huge_memory.c | 7 ++----- mm/mremap.c | 10 ++++------ 3 files changed, 7 insertions(+), 12 deletions(-) --- a/include/linux/huge_mm.h~mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement +++ a/include/linux/huge_mm.h @@ -42,7 +42,7 @@ extern int mincore_huge_pmd(struct vm_ar unsigned long addr, unsigned long end, unsigned char *vec); extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, unsigned long old_end, + unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd); extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, pgprot_t newprot, --- a/mm/huge_memory.c~mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement +++ a/mm/huge_memory.c @@ -1722,17 +1722,14 @@ static pmd_t move_soft_dirty_pmd(pmd_t p } bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, unsigned long old_end, - pmd_t *old_pmd, pmd_t *new_pmd) + unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) { spinlock_t *old_ptl, *new_ptl; pmd_t pmd; struct mm_struct *mm = vma->vm_mm; bool force_flush = false; - if ((old_addr & ~HPAGE_PMD_MASK) || - (new_addr & ~HPAGE_PMD_MASK) || - old_end - old_addr < HPAGE_PMD_SIZE) + if ((old_addr & ~HPAGE_PMD_MASK) || (new_addr & ~HPAGE_PMD_MASK)) return false; /* --- a/mm/mremap.c~mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement +++ a/mm/mremap.c @@ -193,15 +193,13 @@ static void move_ptes(struct vm_area_str #ifdef CONFIG_HAVE_MOVE_PMD static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, unsigned long old_end, - pmd_t *old_pmd, pmd_t *new_pmd) + unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) { spinlock_t *old_ptl, *new_ptl; struct mm_struct *mm = vma->vm_mm; pmd_t pmd; - if ((old_addr & ~PMD_MASK) || (new_addr & ~PMD_MASK) - || old_end - old_addr < PMD_SIZE) + if ((old_addr & ~PMD_MASK) || (new_addr & ~PMD_MASK)) return false; /* @@ -292,7 +290,7 @@ unsigned long move_page_tables(struct vm if (need_rmap_locks) take_rmap_locks(vma); moved = move_huge_pmd(vma, old_addr, new_addr, - old_end, old_pmd, new_pmd); + old_pmd, new_pmd); if (need_rmap_locks) drop_rmap_locks(vma); if (moved) @@ -312,7 +310,7 @@ unsigned long move_page_tables(struct vm if (need_rmap_locks) take_rmap_locks(vma); moved = move_normal_pmd(vma, old_addr, new_addr, - old_end, old_pmd, new_pmd); + old_pmd, new_pmd); if (need_rmap_locks) drop_rmap_locks(vma); if (moved) _