From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f45.google.com (mail-qg0-f45.google.com [209.85.192.45]) by kanga.kvack.org (Postfix) with ESMTP id ED0056B025E for ; Mon, 28 Mar 2016 21:13:13 -0400 (EDT) Received: by mail-qg0-f45.google.com with SMTP id u110so687529qge.3 for ; Mon, 28 Mar 2016 18:13:13 -0700 (PDT) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id h81si3038083qhc.41.2016.03.28.18.13.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Mar 2016 18:13:13 -0700 (PDT) From: Mike Kravetz Subject: [RFC PATCH 1/2] mm/hugetlbfs: Attempt PUD_SIZE mapping alignment if PMD sharing enabled Date: Mon, 28 Mar 2016 18:12:49 -0700 Message-Id: <1459213970-17957-2-git-send-email-mike.kravetz@oracle.com> In-Reply-To: <1459213970-17957-1-git-send-email-mike.kravetz@oracle.com> References: <1459213970-17957-1-git-send-email-mike.kravetz@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org Cc: Hugh Dickins , Naoya Horiguchi , Hillf Danton , "Kirill A. Shutemov" , David Rientjes , Dave Hansen , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Catalin Marinas , Will Deacon , Steve Capper , Andrew Morton , Mike Kravetz When creating a hugetlb mapping, attempt PUD_SIZE alignment if the following conditions are met: - Address passed to mmap or shmat is NULL - The mapping is flaged as shared - The mapping is at least PUD_SIZE in length If a PUD_SIZE aligned mapping can not be created, then fall back to a huge page size mapping. Signed-off-by: Mike Kravetz --- fs/hugetlbfs/inode.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 540ddc9..22b2e38 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -175,6 +175,17 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, struct vm_area_struct *vma; struct hstate *h = hstate_file(file); struct vm_unmapped_area_info info; + bool pud_size_align = false; + unsigned long ret_addr; + + /* + * If PMD sharing is enabled, align to PUD_SIZE to facilitate + * sharing. Only attempt alignment if no address was passed in, + * flags indicate sharing and size is big enough. + */ + if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) && + !addr && flags & MAP_SHARED && len >= PUD_SIZE) + pud_size_align = true; if (len & ~huge_page_mask(h)) return -EINVAL; @@ -199,9 +210,23 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, info.length = len; info.low_limit = TASK_UNMAPPED_BASE; info.high_limit = TASK_SIZE; - info.align_mask = PAGE_MASK & ~huge_page_mask(h); + if (pud_size_align) + info.align_mask = PAGE_MASK & (PUD_SIZE - 1); + else + info.align_mask = PAGE_MASK & ~huge_page_mask(h); info.align_offset = 0; - return vm_unmapped_area(&info); + ret_addr = vm_unmapped_area(&info); + + /* + * If failed with PUD_SIZE alignment, try again with huge page + * size alignment. + */ + if ((ret_addr & ~PAGE_MASK) && pud_size_align) { + info.align_mask = PAGE_MASK & ~huge_page_mask(h); + ret_addr = vm_unmapped_area(&info); + } + + return ret_addr; } #endif -- 2.4.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org