From patchwork Fri Jun 25 01:39:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 467799 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=-15.8 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, SPF_PASS 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 2C657C49EA6 for ; Fri, 25 Jun 2021 01:39:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13EE861220 for ; Fri, 25 Jun 2021 01:39:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233011AbhFYBlj (ORCPT ); Thu, 24 Jun 2021 21:41:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:60348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232917AbhFYBli (ORCPT ); Thu, 24 Jun 2021 21:41:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A0638613C0; Fri, 25 Jun 2021 01:39:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1624585158; bh=z/DEKBCzLKRc2DKKLmysqHv25sO/iXavAcvhtVq+Jhs=; h=Date:From:To:Subject:In-Reply-To:From; b=sqkegw2FyJC7iO/2FeFVuMvOgdFgP9IgUFWunkDlxvKQVjVuTKkHary5bfsd6ZD/p nP2LR7p2MUwU3iaVTJGlOWEV/i8KMf8lMewxG4LLRBGTFznzH6yH3dl3jU2XZPgEuM OOkdmwVolW2kUTxtcqoB600CByRH9nTjcN7ufr0I= Date: Thu, 24 Jun 2021 18:39:17 -0700 From: Andrew Morton To: akpm@linux-foundation.org, apopple@nvidia.com, hughd@google.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, peterx@redhat.com, rcampbell@nvidia.com, shy828301@gmail.com, stable@vger.kernel.org, torvalds@linux-foundation.org, wangyugui@e16-tech.com, will@kernel.org, willy@infradead.org, ziy@nvidia.com Subject: [patch 06/24] mm: page_vma_mapped_walk(): add a level of indentation Message-ID: <20210625013917.v1e2AXMQO%akpm@linux-foundation.org> In-Reply-To: <20210624183838.ac3161ca4a43989665ac8b2f@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Hugh Dickins Subject: mm: page_vma_mapped_walk(): add a level of indentation page_vma_mapped_walk() cleanup: add a level of indentation to much of the body, making no functional change in this commit, but reducing the later diff when this is all converted to a loop. [hughd@google.com: : page_vma_mapped_walk(): add a level of indentation fix] Link: https://lkml.kernel.org/r/7f817555-3ce1-c785-e438-87d8efdcaf26@google.com Link: https://lkml.kernel.org/r/efde211-f3e2-fe54-977-ef481419e7f3@google.com Signed-off-by: Hugh Dickins Acked-by: Kirill A. Shutemov Cc: Alistair Popple Cc: Matthew Wilcox Cc: Peter Xu Cc: Ralph Campbell Cc: Wang Yugui Cc: Will Deacon Cc: Yang Shi Cc: Zi Yan Cc: Signed-off-by: Andrew Morton --- mm/page_vma_mapped.c | 105 +++++++++++++++++++++-------------------- 1 file changed, 55 insertions(+), 50 deletions(-) --- a/mm/page_vma_mapped.c~mm-page_vma_mapped_walk-add-a-level-of-indentation +++ a/mm/page_vma_mapped.c @@ -173,62 +173,67 @@ bool page_vma_mapped_walk(struct page_vm if (pvmw->pte) goto next_pte; restart: - pgd = pgd_offset(mm, pvmw->address); - if (!pgd_present(*pgd)) - return false; - p4d = p4d_offset(pgd, pvmw->address); - if (!p4d_present(*p4d)) - return false; - pud = pud_offset(p4d, pvmw->address); - if (!pud_present(*pud)) - return false; - pvmw->pmd = pmd_offset(pud, pvmw->address); - /* - * Make sure the pmd value isn't cached in a register by the - * compiler and used as a stale value after we've observed a - * subsequent update. - */ - pmde = READ_ONCE(*pvmw->pmd); - if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) { - pvmw->ptl = pmd_lock(mm, pvmw->pmd); - pmde = *pvmw->pmd; - if (likely(pmd_trans_huge(pmde))) { - if (pvmw->flags & PVMW_MIGRATION) - return not_found(pvmw); - if (pmd_page(pmde) != page) - return not_found(pvmw); - return true; - } - if (!pmd_present(pmde)) { - swp_entry_t entry; + { + pgd = pgd_offset(mm, pvmw->address); + if (!pgd_present(*pgd)) + return false; + p4d = p4d_offset(pgd, pvmw->address); + if (!p4d_present(*p4d)) + return false; + pud = pud_offset(p4d, pvmw->address); + if (!pud_present(*pud)) + return false; - if (!thp_migration_supported() || - !(pvmw->flags & PVMW_MIGRATION)) - return not_found(pvmw); - entry = pmd_to_swp_entry(pmde); - if (!is_migration_entry(entry) || - migration_entry_to_page(entry) != page) - return not_found(pvmw); - return true; - } - /* THP pmd was split under us: handle on pte level */ - spin_unlock(pvmw->ptl); - pvmw->ptl = NULL; - } else if (!pmd_present(pmde)) { + pvmw->pmd = pmd_offset(pud, pvmw->address); /* - * If PVMW_SYNC, take and drop THP pmd lock so that we - * cannot return prematurely, while zap_huge_pmd() has - * cleared *pmd but not decremented compound_mapcount(). + * Make sure the pmd value isn't cached in a register by the + * compiler and used as a stale value after we've observed a + * subsequent update. */ - if ((pvmw->flags & PVMW_SYNC) && PageTransCompound(page)) { - spinlock_t *ptl = pmd_lock(mm, pvmw->pmd); + pmde = READ_ONCE(*pvmw->pmd); + + if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) { + pvmw->ptl = pmd_lock(mm, pvmw->pmd); + pmde = *pvmw->pmd; + if (likely(pmd_trans_huge(pmde))) { + if (pvmw->flags & PVMW_MIGRATION) + return not_found(pvmw); + if (pmd_page(pmde) != page) + return not_found(pvmw); + return true; + } + if (!pmd_present(pmde)) { + swp_entry_t entry; - spin_unlock(ptl); + if (!thp_migration_supported() || + !(pvmw->flags & PVMW_MIGRATION)) + return not_found(pvmw); + entry = pmd_to_swp_entry(pmde); + if (!is_migration_entry(entry) || + migration_entry_to_page(entry) != page) + return not_found(pvmw); + return true; + } + /* THP pmd was split under us: handle on pte level */ + spin_unlock(pvmw->ptl); + pvmw->ptl = NULL; + } else if (!pmd_present(pmde)) { + /* + * If PVMW_SYNC, take and drop THP pmd lock so that we + * cannot return prematurely, while zap_huge_pmd() has + * cleared *pmd but not decremented compound_mapcount(). + */ + if ((pvmw->flags & PVMW_SYNC) && + PageTransCompound(page)) { + spinlock_t *ptl = pmd_lock(mm, pvmw->pmd); + + spin_unlock(ptl); + } + return false; } - return false; + if (!map_pte(pvmw)) + goto next_pte; } - if (!map_pte(pvmw)) - goto next_pte; while (1) { unsigned long end;