From patchwork Fri May 27 19:07:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiaqi Yan X-Patchwork-Id: 12863717 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B717FC433EF for ; Fri, 27 May 2022 19:07:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 568138D0005; Fri, 27 May 2022 15:07:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 517838D0001; Fri, 27 May 2022 15:07:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 434228D0005; Fri, 27 May 2022 15:07:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 2F0668D0001 for ; Fri, 27 May 2022 15:07:41 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 0902920C26 for ; Fri, 27 May 2022 19:07:41 +0000 (UTC) X-FDA: 79512457122.10.F2577BC Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) by imf16.hostedemail.com (Postfix) with ESMTP id A757D18005E for ; Fri, 27 May 2022 19:07:24 +0000 (UTC) Received: by mail-pf1-f201.google.com with SMTP id d207-20020a621dd8000000b00518119a0e6cso2835864pfd.8 for ; Fri, 27 May 2022 12:07:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=8VyqWzHxe+Fi0TJWRkAxpRJACnpVixCrEKq15aeFivc=; b=T74n+oAwjh+y9KstIaNuJYbthoHtu9yqVsKHxdNQqCCzoki4Rb9qoQd9Jz/nuLsIS9 QqNVlPhpzT7q0A1x4CEfJnyEgCsa64FaEe5GBMpSG0O0Dy9YzdXhmtronwp4ePQM91Di lBRCFVugQ/p1hw86mk2Lq/dKvcCvy0PYtJ4bLPK9pm6eMUl5qob8GnYuo+NRwnmBGTbd ZT5WapyW6nRJ7p166HvppqcpcucHlRv5IcCSWnG3n9CeeLOBxvUYYVHgSp/bozoOOrU7 qa82RZRZn7j3gHg6uv/XReU38HQm3BN2YVWuAay0+eOAwncXae5OG4DBM8aB+JnLfARI TFRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=8VyqWzHxe+Fi0TJWRkAxpRJACnpVixCrEKq15aeFivc=; b=lx2V2hNWoo/9eGud/8m5hBbJFo9hbGSer0SG89gnj43Vn0cCwy58QPqIuCDmY/8UMG nJKoU5ugHrJSIqR/CawUGh8Ts6CgCv7o8j+Onvx4ZQt9pdxeus/OGBkgeMN87IyKYJ8Z ACZG8NQPuY+2WGS5483a5zaM85h69qzCLBDoFRr5LhyptTJCFrB4mVxWXAmNlp01WK0F ouynrLUtg6ymiMzsBQc+iT5sJGk4rem/uOFt4EInRKdHj05Iubvx9a5X1QqKJonE30+r BRi3M5zrMq7U4PhjDmPAsjchiMPSSd6U7X7nmx+4qpnFmP7VjX3lsGNFWw8IOwLQ/jBj 9Xew== X-Gm-Message-State: AOAM5304SwFCNDd5YXemaz9rymYonzqOPa8rxiY88oqzx/v56Cvb9qN7 239tAf/YTHHFLIZV8kMBdhbDAJ/AKCxKqg== X-Google-Smtp-Source: ABdhPJxcKt+KrK1sCtybY2KE/pkYWjEb6frines+6VWUZCC1ijBNHQBfjHtk0MQQ0nddjULsQD1TipKPaVMJLw== X-Received: from yjqkernel.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1837]) (user=jiaqiyan job=sendgmr) by 2002:a17:90a:be10:b0:1e2:80f5:948b with SMTP id a16-20020a17090abe1000b001e280f5948bmr3874972pjs.94.1653678458589; Fri, 27 May 2022 12:07:38 -0700 (PDT) Date: Fri, 27 May 2022 12:07:30 -0700 In-Reply-To: <20220527190731.322722-1-jiaqiyan@google.com> Message-Id: <20220527190731.322722-2-jiaqiyan@google.com> Mime-Version: 1.0 References: <20220527190731.322722-1-jiaqiyan@google.com> X-Mailer: git-send-email 2.36.1.124.g0e6072fb45-goog Subject: [PATCH v4 1/2] mm: khugepaged: recover from poisoned anonymous memory From: Jiaqi Yan To: shy828301@gmail.com, tongtiangen@huawei.com Cc: tony.luck@intel.com, naoya.horiguchi@nec.com, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, juew@google.com, jiaqiyan@google.com, linux-mm@kvack.org X-Stat-Signature: g85ny476hunqieacsknnwiyhxrnmyiwd X-Rspam-User: Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=T74n+oAw; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf16.hostedemail.com: domain of 3eiGRYggKCB0CB3JBR3G9HH9E7.5HFEBGNQ-FFDO35D.HK9@flex--jiaqiyan.bounces.google.com designates 209.85.210.201 as permitted sender) smtp.mailfrom=3eiGRYggKCB0CB3JBR3G9HH9E7.5HFEBGNQ-FFDO35D.HK9@flex--jiaqiyan.bounces.google.com X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: A757D18005E X-HE-Tag: 1653678444-781590 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Make __collapse_huge_page_copy return whether collapsing/copying anonymous pages succeeded, and make collapse_huge_page handle the return status. Break existing PTE scan loop into two for-loops. The first loop copies source pages into target huge page, and can fail gracefully when running into memory errors in source pages. If copying all pages succeeds, the second loop releases and clears up these normal pages. Otherwise, the second loop does the following to roll back the page table and page states: 1) re-establish the original PTEs-to-PMD connection. 2) release source pages back to their LRU list. Signed-off-by: Jiaqi Yan Reviewed-by: Yang Shi --- include/linux/highmem.h | 19 +++++ include/trace/events/huge_memory.h | 3 +- mm/khugepaged.c | 130 ++++++++++++++++++++++------- 3 files changed, 121 insertions(+), 31 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 39bb9b47fa9cd..0ccb1e92c4b06 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -298,6 +298,25 @@ static inline void copy_highpage(struct page *to, struct page *from) #endif +/* + * Machine check exception handled version of copy_highpage. + * Return true if copying page content failed; otherwise false. + * Note handling #MC requires arch opt-in. + */ +static inline bool copy_highpage_mc(struct page *to, struct page *from) +{ + char *vfrom, *vto; + unsigned long ret; + + vfrom = kmap_local_page(from); + vto = kmap_local_page(to); + ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE); + kunmap_local(vto); + kunmap_local(vfrom); + + return ret > 0; +} + static inline void memcpy_page(struct page *dst_page, size_t dst_off, struct page *src_page, size_t src_off, size_t len) diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h index 4fdb14a81108b..f08687046ce41 100644 --- a/include/trace/events/huge_memory.h +++ b/include/trace/events/huge_memory.h @@ -34,7 +34,8 @@ EM( SCAN_ALLOC_HUGE_PAGE_FAIL, "alloc_huge_page_failed") \ EM( SCAN_CGROUP_CHARGE_FAIL, "ccgroup_charge_failed") \ EM( SCAN_TRUNCATED, "truncated") \ - EMe(SCAN_PAGE_HAS_PRIVATE, "page_has_private") \ + EM( SCAN_PAGE_HAS_PRIVATE, "page_has_private") \ + EMe(SCAN_COPY_MC, "copy_poisoned_page") \ #undef EM #undef EMe diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 131492fd1148b..0dd28ecc915d1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -52,6 +52,7 @@ enum scan_result { SCAN_CGROUP_CHARGE_FAIL, SCAN_TRUNCATED, SCAN_PAGE_HAS_PRIVATE, + SCAN_COPY_MC, }; #define CREATE_TRACE_POINTS @@ -739,44 +740,99 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, return 0; } -static void __collapse_huge_page_copy(pte_t *pte, struct page *page, - struct vm_area_struct *vma, - unsigned long address, - spinlock_t *ptl, - struct list_head *compound_pagelist) +/* + * __collapse_huge_page_copy - attempts to copy memory contents from normal + * pages to a hugepage. Cleanup the normal pages if copying succeeds; + * otherwise restore the original page table and release isolated normal pages. + * Returns true if copying succeeds, otherwise returns false. + * + * @pte: starting of the PTEs to copy from + * @page: the new hugepage to copy contents to + * @pmd: pointer to the new hugepage's PMD + * @rollback: the original normal pages' PMD + * @address: starting address to copy + * @pte_ptl: lock on normal pages' PTEs + * @compound_pagelist: list that stores compound pages + */ +static bool __collapse_huge_page_copy(pte_t *pte, + struct page *page, + pmd_t *pmd, + pmd_t rollback, + struct vm_area_struct *vma, + unsigned long address, + spinlock_t *pte_ptl, + struct list_head *compound_pagelist) { struct page *src_page, *tmp; pte_t *_pte; - for (_pte = pte; _pte < pte + HPAGE_PMD_NR; - _pte++, page++, address += PAGE_SIZE) { - pte_t pteval = *_pte; + pte_t pteval; + unsigned long _address; + spinlock_t *pmd_ptl; + bool copy_succeeded = true; - if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { + /* + * Copying pages' contents is subject to memory poison at any iteration. + */ + for (_pte = pte, _address = address; + _pte < pte + HPAGE_PMD_NR; + _pte++, page++, _address += PAGE_SIZE) { + pteval = *_pte; + + if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) clear_user_highpage(page, address); - add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); - if (is_zero_pfn(pte_pfn(pteval))) { - /* - * ptl mostly unnecessary. - */ - spin_lock(ptl); - ptep_clear(vma->vm_mm, address, _pte); - spin_unlock(ptl); + else { + src_page = pte_page(pteval); + if (copy_highpage_mc(page, src_page)) { + copy_succeeded = false; + break; + } + } + } + + if (!copy_succeeded) { + /* + * Copying failed, re-establish the regular PMD that points to + * the regular page table. Restoring PMD needs to be done prior + * to releasing pages. Since pages are still isolated and locked + * here, acquiring anon_vma_lock_write is unnecessary. + */ + pmd_ptl = pmd_lock(vma->vm_mm, pmd); + pmd_populate(vma->vm_mm, pmd, pmd_pgtable(rollback)); + spin_unlock(pmd_ptl); + } + + for (_pte = pte, _address = address; _pte < pte + HPAGE_PMD_NR; + _pte++, _address += PAGE_SIZE) { + pteval = *_pte; + if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { + if (copy_succeeded) { + add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); + if (is_zero_pfn(pte_pfn(pteval))) { + /* + * ptl mostly unnecessary. + */ + spin_lock(pte_ptl); + pte_clear(vma->vm_mm, _address, _pte); + spin_unlock(pte_ptl); + } } } else { src_page = pte_page(pteval); - copy_user_highpage(page, src_page, address, vma); if (!PageCompound(src_page)) release_pte_page(src_page); - /* - * ptl mostly unnecessary, but preempt has to - * be disabled to update the per-cpu stats - * inside page_remove_rmap(). - */ - spin_lock(ptl); - ptep_clear(vma->vm_mm, address, _pte); - page_remove_rmap(src_page, false); - spin_unlock(ptl); - free_page_and_swap_cache(src_page); + + if (copy_succeeded) { + /* + * ptl mostly unnecessary, but preempt has to + * be disabled to update the per-cpu stats + * inside page_remove_rmap(). + */ + spin_lock(pte_ptl); + pte_clear(vma->vm_mm, _address, _pte); + page_remove_rmap(src_page, false); + spin_unlock(pte_ptl); + free_page_and_swap_cache(src_page); + } } } @@ -784,6 +840,8 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page, list_del(&src_page->lru); release_pte_page(src_page); } + + return copy_succeeded; } static void khugepaged_alloc_sleep(void) @@ -1066,6 +1124,7 @@ static void collapse_huge_page(struct mm_struct *mm, struct vm_area_struct *vma; struct mmu_notifier_range range; gfp_t gfp; + bool copied = false; VM_BUG_ON(address & ~HPAGE_PMD_MASK); @@ -1177,9 +1236,13 @@ static void collapse_huge_page(struct mm_struct *mm, */ anon_vma_unlock_write(vma->anon_vma); - __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl, - &compound_pagelist); + copied = __collapse_huge_page_copy(pte, new_page, pmd, _pmd, + vma, address, pte_ptl, &compound_pagelist); pte_unmap(pte); + if (!copied) { + result = SCAN_COPY_MC; + goto out_up_write; + } /* * spin_lock() below is not the equivalent of smp_wmb(), but * the smp_wmb() inside __SetPageUptodate() can be reused to @@ -2168,6 +2231,13 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, khugepaged_scan_file(mm, file, pgoff, hpage); fput(file); } else { + /* + * mmap_read_lock is + * 1) still held if scan failed; + * 2) released if scan succeeded. + * It is not affected by collapsing or copying + * operations. + */ ret = khugepaged_scan_pmd(mm, vma, khugepaged_scan.address, hpage);