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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 C9081C282CE for ; Tue, 4 Jun 2019 16:52:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 96C1623D01 for ; Tue, 4 Jun 2019 16:52:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="Ou6wWs+h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728004AbfFDQwF (ORCPT ); Tue, 4 Jun 2019 12:52:05 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:50476 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727900AbfFDQv6 (ORCPT ); Tue, 4 Jun 2019 12:51:58 -0400 Received: from pps.filterd (m0001255.ppops.net [127.0.0.1]) by mx0b-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x54Gev1U030380 for ; Tue, 4 Jun 2019 09:51:57 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=Dvy8H8Me5IhbWeZE5T8MjN8uMJLZ8NXUKaabsq8Cic4=; b=Ou6wWs+hOMKUtCOADrukHWccLV9czCMuqvnZ0cwB2fbFH+0j8l3XbwMmI/Hu3dEvrpqb 6iAFbuh7jDr8sgCJoqPWHDpT4g1TIKlzfq4OxXR5aWmc81f2N1iukMO5ZWt3cKd8o/VC 2e3Z1xTRKTbucIT8RiMMyTJPUlW/0A7R/gQ= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0b-00082601.pphosted.com with ESMTP id 2swh56j3br-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 04 Jun 2019 09:51:56 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 4 Jun 2019 09:51:55 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 8A48A62E1EE3; Tue, 4 Jun 2019 09:51:52 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: , CC: , , , , , , , Song Liu Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH uprobe, thp v2 5/5] uprobe: collapse THP pmd after removing all uprobes Date: Tue, 4 Jun 2019 09:51:38 -0700 Message-ID: <20190604165138.1520916-6-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190604165138.1520916-1-songliubraving@fb.com> References: <20190604165138.1520916-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-04_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=786 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906040106 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After all uprobes are removed from the huge page (with PTE pgtable), it is possible to collapse the pmd and benefit from THP again. This patch does the collapse. An issue on earlier version was discovered by kbuild test robot. Reported-by: kbuild test robot Signed-off-by: Song Liu --- include/linux/huge_mm.h | 7 +++++ kernel/events/uprobes.c | 3 ++ mm/huge_memory.c | 70 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 80 insertions(+) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 7cd5c150c21d..b969022dc922 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -250,6 +250,9 @@ static inline bool thp_migration_supported(void) return IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION); } +extern inline void try_collapse_huge_pmd(struct vm_area_struct *vma, + struct page *page); + #else /* CONFIG_TRANSPARENT_HUGEPAGE */ #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; }) #define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; }) @@ -368,6 +371,10 @@ static inline bool thp_migration_supported(void) { return false; } + +static inline void try_collapse_huge_pmd(struct vm_area_struct *vma, + struct page *page) {} + #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif /* _LINUX_HUGE_MM_H */ diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 88a8e1624bfa..0c8e2358dbf5 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -537,6 +537,9 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, if (ret && is_register && ref_ctr_updated) update_ref_ctr(uprobe, mm, -1); + if (!ret && orig_page && PageTransCompound(orig_page)) + try_collapse_huge_pmd(vma, orig_page); + return ret; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9f8bce9a6b32..03855a480fd2 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2886,6 +2886,76 @@ static struct shrinker deferred_split_shrinker = { .flags = SHRINKER_NUMA_AWARE, }; +/** + * try_collapse_huge_pmd - try collapse pmd for a pte mapped huge page + * @vma: vma containing the huge page + * @page: any sub page of the huge page + */ +void try_collapse_huge_pmd(struct vm_area_struct *vma, + struct page *page) +{ + struct page *hpage = compound_head(page); + struct mm_struct *mm = vma->vm_mm; + struct mmu_notifier_range range; + unsigned long haddr; + unsigned long addr; + pmd_t *pmd, _pmd; + int i, count = 0; + spinlock_t *ptl; + + VM_BUG_ON_PAGE(!PageCompound(page), page); + + haddr = page_address_in_vma(hpage, vma); + pmd = mm_find_pmd(mm, haddr); + if (!pmd) + return; + + ptl = pmd_lock(mm, pmd); + + /* step 1: check all mapped PTEs */ + for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { + pte_t *pte = pte_offset_map(pmd, addr); + + if (pte_none(*pte)) + continue; + if (hpage + i != vm_normal_page(vma, addr, *pte)) { + spin_unlock(ptl); + return; + } + count++; + } + + /* step 2: adjust rmap and refcount */ + for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { + pte_t *pte = pte_offset_map(pmd, addr); + struct page *p; + + if (pte_none(*pte)) + continue; + p = vm_normal_page(vma, addr, *pte); + lock_page(p); + page_remove_rmap(p, false); + unlock_page(p); + put_page(p); + } + + /* step 3: flip page table */ + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm, + haddr, haddr + HPAGE_PMD_SIZE); + mmu_notifier_invalidate_range_start(&range); + + _pmd = pmdp_collapse_flush(vma, haddr, pmd); + spin_unlock(ptl); + mmu_notifier_invalidate_range_end(&range); + + /* step 4: free pgtable, clean up counters, etc. */ + mm_dec_nr_ptes(mm); + pte_free(mm, pmd_pgtable(_pmd)); + add_mm_counter(mm, + shmem_file(vma->vm_file) ? MM_SHMEMPAGES : MM_FILEPAGES, + -count); +} + #ifdef CONFIG_DEBUG_FS static int split_huge_pages_set(void *data, u64 val) { -- 2.17.1