From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 894E06B0003 for ; Tue, 22 May 2018 15:44:37 -0400 (EDT) Received: by mail-wr0-f199.google.com with SMTP id 3-v6so15411752wry.0 for ; Tue, 22 May 2018 12:44:37 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTPS id t55-v6si447727edb.420.2018.05.22.12.44.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 May 2018 12:44:35 -0700 (PDT) Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w4MJeMCS013681 for ; Tue, 22 May 2018 12:44:33 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2j4r8788tr-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Tue, 22 May 2018 12:44:33 -0700 From: Song Liu Subject: [PATCH v2] mm/THP: use hugepage_vma_check() in khugepaged_enter_vma_merge() Date: Tue, 22 May 2018 12:44:30 -0700 Message-ID: <20180522194430.426688-1-songliubraving@fb.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: kernel-team@fb.com, Song Liu , linux-kernel@vger.kernel.org, mhocko@kernel.org, rientjes@google.com, aarcange@redhat.com, kirill@shutemov.name khugepaged_enter_vma_merge() is using a different approach to check whether a vma is valid for khugepaged_enter(): if (!vma->anon_vma) /* * Not yet faulted in so we will register later in the * page fault if needed. */ return 0; if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED)) /* khugepaged not yet working on file or special mappings */ return 0; This check has some problems. One of the obvious problems is that it doesn't check shmem_file(), so that vma backed with shmem files will not call khugepaged_enter(). Here is an example of failed madvise(): /* mount /dev/shm with huge=advise: * mount -o remount,huge=advise /dev/shm */ /* create file /dev/shm/huge */ #define HUGE_FILE "/dev/shm/huge" fd = open(HUGE_FILE, O_RDONLY); ptr = mmap(NULL, FILE_SIZE, PROT_READ, MAP_PRIVATE, fd, 0); ret = madvise(ptr, FILE_SIZE, MADV_HUGEPAGE); madvise() will return 0, but this memory region is never put in huge page (check from /proc/meminfo: ShmemHugePages). This patch fixes these problems by reusing hugepage_vma_check() in khugepaged_enter_vma_merge(). vma->vm_flags is not yet updated in khugepaged_enter_vma_merge(), so we need to pass the new vm_flags to hugepage_vma_check() through a separate argument. Signed-off-by: Song Liu --- mm/khugepaged.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index d7b2a4b..9f74e51 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -430,18 +430,15 @@ int __khugepaged_enter(struct mm_struct *mm) return 0; } +static bool hugepage_vma_check(struct vm_area_struct *vma, + unsigned long vm_flags); + int khugepaged_enter_vma_merge(struct vm_area_struct *vma, unsigned long vm_flags) { unsigned long hstart, hend; - if (!vma->anon_vma) - /* - * Not yet faulted in so we will register later in the - * page fault if needed. - */ - return 0; - if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED)) - /* khugepaged not yet working on file or special mappings */ + + if (!hugepage_vma_check(vma, vm_flags)) return 0; hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; @@ -819,10 +816,11 @@ khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node) } #endif -static bool hugepage_vma_check(struct vm_area_struct *vma) +static bool hugepage_vma_check(struct vm_area_struct *vma, + unsigned long vm_flags) { - if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || - (vma->vm_flags & VM_NOHUGEPAGE) || + if ((!(vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || + (vm_flags & VM_NOHUGEPAGE) || test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) return false; if (shmem_file(vma->vm_file)) { @@ -835,7 +833,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma) return false; if (is_vma_temporary_stack(vma)) return false; - return !(vma->vm_flags & VM_NO_KHUGEPAGED); + return !(vm_flags & VM_NO_KHUGEPAGED); } /* @@ -862,7 +860,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, hend = vma->vm_end & HPAGE_PMD_MASK; if (address < hstart || address + HPAGE_PMD_SIZE > hend) return SCAN_ADDRESS_RANGE; - if (!hugepage_vma_check(vma)) + if (!hugepage_vma_check(vma, vma->vm_flags)) return SCAN_VMA_CHECK; return 0; } @@ -1694,7 +1692,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, progress++; break; } - if (!hugepage_vma_check(vma)) { + if (!hugepage_vma_check(vma, vma->vm_flags)) { skip: progress++; continue; -- 2.9.5