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[156.151.31.81]) by mx.google.com with ESMTPS id o63si19116086pfi.141.2016.03.28.18.13.13 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 2/2] x86/hugetlb: Attempt PUD_SIZE mapping alignment if PMD sharing enabled Date: Mon, 28 Mar 2016 18:12:50 -0700 Message-Id: <1459213970-17957-3-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 --- arch/x86/mm/hugetlbpage.c | 64 ++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 61 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c index 42982b2..4f53af5 100644 --- a/arch/x86/mm/hugetlbpage.c +++ b/arch/x86/mm/hugetlbpage.c @@ -78,14 +78,39 @@ static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, { 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; info.flags = 0; info.length = len; info.low_limit = current->mm->mmap_legacy_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; } static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, @@ -95,16 +120,38 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, struct hstate *h = hstate_file(file); struct vm_unmapped_area_info info; unsigned long addr; + bool pud_size_align = false; + + /* + * 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) && + !addr0 && flags & MAP_SHARED && len >= PUD_SIZE) + pud_size_align = true; info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.length = len; info.low_limit = PAGE_SIZE; info.high_limit = current->mm->mmap_base; - 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; addr = vm_unmapped_area(&info); /* + * If failed with PUD_SIZE alignment, try again with huge page + * size alignment. + */ + if ((addr & ~PAGE_MASK) && pud_size_align) { + info.align_mask = PAGE_MASK & ~huge_page_mask(h); + addr = vm_unmapped_area(&info); + } + + /* * A failed mmap() very likely causes application failure, * so fall back to the bottom-up function here. This scenario * can happen with large stack limits and large mmap() @@ -115,7 +162,18 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, info.flags = 0; info.low_limit = TASK_UNMAPPED_BASE; info.high_limit = TASK_SIZE; + if (pud_size_align) + info.align_mask = PAGE_MASK & (PUD_SIZE - 1); addr = vm_unmapped_area(&info); + + /* + * If failed again with PUD_SIZE alignment, finally try with + * huge page size alignment. + */ + if (addr & ~PAGE_MASK) { + info.align_mask = PAGE_MASK & ~huge_page_mask(h); + addr = vm_unmapped_area(&info); + } } return addr; -- 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