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=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 5B3DEC67839 for ; Fri, 14 Dec 2018 06:28:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 241142086D for ; Fri, 14 Dec 2018 06:28:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 241142086D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728850AbeLNG2a (ORCPT ); Fri, 14 Dec 2018 01:28:30 -0500 Received: from mga07.intel.com ([134.134.136.100]:52323 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728759AbeLNG21 (ORCPT ); Fri, 14 Dec 2018 01:28:27 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Dec 2018 22:28:27 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,351,1539673200"; d="scan'208";a="125841066" Received: from yhuang-mobile.sh.intel.com ([10.239.197.226]) by fmsmga002.fm.intel.com with ESMTP; 13 Dec 2018 22:28:24 -0800 From: Huang Ying To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , "Kirill A. Shutemov" , Andrea Arcangeli , Michal Hocko , Johannes Weiner , Shaohua Li , Hugh Dickins , Minchan Kim , Rik van Riel , Dave Hansen , Naoya Horiguchi , Zi Yan , Daniel Jordan Subject: [PATCH -V9 16/21] swap: Support to copy PMD swap mapping when fork() Date: Fri, 14 Dec 2018 14:27:49 +0800 Message-Id: <20181214062754.13723-17-ying.huang@intel.com> X-Mailer: git-send-email 2.18.1 In-Reply-To: <20181214062754.13723-1-ying.huang@intel.com> References: <20181214062754.13723-1-ying.huang@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org During fork, the page table need to be copied from parent to child. A PMD swap mapping need to be copied too and the swap reference count need to be increased. When the huge swap cluster has been split already, we need to split the PMD swap mapping and fallback to PTE copying. When swap count continuation failed to allocate a page with GFP_ATOMIC, we need to unlock the spinlock and try again with GFP_KERNEL. Signed-off-by: "Huang, Ying" Cc: "Kirill A. Shutemov" Cc: Andrea Arcangeli Cc: Michal Hocko Cc: Johannes Weiner Cc: Shaohua Li Cc: Hugh Dickins Cc: Minchan Kim Cc: Rik van Riel Cc: Dave Hansen Cc: Naoya Horiguchi Cc: Zi Yan Cc: Daniel Jordan --- mm/huge_memory.c | 72 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 57 insertions(+), 15 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e460241ea761..b083c66a9d09 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -974,6 +974,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, if (unlikely(!pgtable)) goto out; +retry: dst_ptl = pmd_lock(dst_mm, dst_pmd); src_ptl = pmd_lockptr(src_mm, src_pmd); spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); @@ -981,26 +982,67 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, ret = -EAGAIN; pmd = *src_pmd; -#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION if (unlikely(is_swap_pmd(pmd))) { swp_entry_t entry = pmd_to_swp_entry(pmd); - VM_BUG_ON(!is_pmd_migration_entry(pmd)); - if (is_write_migration_entry(entry)) { - make_migration_entry_read(&entry); - pmd = swp_entry_to_pmd(entry); - if (pmd_swp_soft_dirty(*src_pmd)) - pmd = pmd_swp_mksoft_dirty(pmd); - set_pmd_at(src_mm, addr, src_pmd, pmd); +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + if (is_migration_entry(entry)) { + if (is_write_migration_entry(entry)) { + make_migration_entry_read(&entry); + pmd = swp_entry_to_pmd(entry); + if (pmd_swp_soft_dirty(*src_pmd)) + pmd = pmd_swp_mksoft_dirty(pmd); + set_pmd_at(src_mm, addr, src_pmd, pmd); + } + add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); + mm_inc_nr_ptes(dst_mm); + pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); + set_pmd_at(dst_mm, addr, dst_pmd, pmd); + ret = 0; + goto out_unlock; } - add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); - mm_inc_nr_ptes(dst_mm); - pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); - set_pmd_at(dst_mm, addr, dst_pmd, pmd); - ret = 0; - goto out_unlock; - } #endif + if (IS_ENABLED(CONFIG_THP_SWAP) && !non_swap_entry(entry)) { + ret = swap_duplicate(&entry, HPAGE_PMD_NR); + if (!ret) { + add_mm_counter(dst_mm, MM_SWAPENTS, + HPAGE_PMD_NR); + mm_inc_nr_ptes(dst_mm); + pgtable_trans_huge_deposit(dst_mm, dst_pmd, + pgtable); + set_pmd_at(dst_mm, addr, dst_pmd, pmd); + /* make sure dst_mm is on swapoff's mmlist. */ + if (unlikely(list_empty(&dst_mm->mmlist))) { + spin_lock(&mmlist_lock); + if (list_empty(&dst_mm->mmlist)) + list_add(&dst_mm->mmlist, + &src_mm->mmlist); + spin_unlock(&mmlist_lock); + } + } else if (ret == -ENOTDIR) { + /* + * The huge swap cluster has been split, split + * the PMD swap mapping and fallback to PTE + */ + __split_huge_swap_pmd(vma, addr, src_pmd); + pte_free(dst_mm, pgtable); + } else if (ret == -ENOMEM) { + spin_unlock(src_ptl); + spin_unlock(dst_ptl); + ret = add_swap_count_continuation(entry, + GFP_KERNEL); + if (ret < 0) { + ret = -ENOMEM; + pte_free(dst_mm, pgtable); + goto out; + } + goto retry; + } else + VM_BUG_ON(1); + goto out_unlock; + } + VM_BUG_ON(1); + } if (unlikely(!pmd_trans_huge(pmd))) { pte_free(dst_mm, pgtable); -- 2.18.1