From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f70.google.com (mail-it0-f70.google.com [209.85.214.70]) by kanga.kvack.org (Postfix) with ESMTP id 3222B82F64 for ; Mon, 29 Aug 2016 15:34:23 -0400 (EDT) Received: by mail-it0-f70.google.com with SMTP id 15so3008884ita.1 for ; Mon, 29 Aug 2016 12:34:23 -0700 (PDT) Received: from mail-oi0-x229.google.com (mail-oi0-x229.google.com. [2607:f8b0:4003:c06::229]) by mx.google.com with ESMTPS id j47si25760737otd.90.2016.08.29.12.34.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Aug 2016 12:34:22 -0700 (PDT) Received: by mail-oi0-x229.google.com with SMTP id j203so64124900oih.2 for ; Mon, 29 Aug 2016 12:34:22 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1472497881-9323-2-git-send-email-toshi.kani@hpe.com> References: <1472497881-9323-1-git-send-email-toshi.kani@hpe.com> <1472497881-9323-2-git-send-email-toshi.kani@hpe.com> From: Dan Williams Date: Mon, 29 Aug 2016 12:34:21 -0700 Message-ID: Subject: Re: [PATCH v4 RESEND 1/2] thp, dax: add thp_get_unmapped_area for pmd mappings Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Toshi Kani Cc: Andrew Morton , Matthew Wilcox , Ross Zwisler , "Kirill A. Shutemov" , david , Jan Kara , Theodore Ts'o , Andreas Dilger , mike.kravetz@oracle.com, "linux-nvdimm@lists.01.org" , linux-fsdevel , Linux MM , "linux-kernel@vger.kernel.org" On Mon, Aug 29, 2016 at 12:11 PM, Toshi Kani wrote: > When CONFIG_FS_DAX_PMD is set, DAX supports mmap() using pmd page > size. This feature relies on both mmap virtual address and FS > block (i.e. physical address) to be aligned by the pmd page size. > Users can use mkfs options to specify FS to align block allocations. > However, aligning mmap address requires code changes to existing > applications for providing a pmd-aligned address to mmap(). > > For instance, fio with "ioengine=mmap" performs I/Os with mmap() [1]. > It calls mmap() with a NULL address, which needs to be changed to > provide a pmd-aligned address for testing with DAX pmd mappings. > Changing all applications that call mmap() with NULL is undesirable. > > Add thp_get_unmapped_area(), which can be called by filesystem's > get_unmapped_area to align an mmap address by the pmd size for > a DAX file. It calls the default handler, mm->get_unmapped_area(), > to find a range and then aligns it for a DAX file. > > The patch is based on Matthew Wilcox's change that allows adding > support of the pud page size easily. > > [1]: https://github.com/axboe/fio/blob/master/engines/mmap.c > Signed-off-by: Toshi Kani > Cc: Andrew Morton > Cc: Dan Williams > Cc: Matthew Wilcox > Cc: Ross Zwisler > Cc: Kirill A. Shutemov > Cc: Dave Chinner > Cc: Jan Kara > Cc: Theodore Ts'o > Cc: Andreas Dilger > Cc: Mike Kravetz > --- Reviewed-by: Dan Williams ...with one minor nit: > include/linux/huge_mm.h | 7 +++++++ > mm/huge_memory.c | 43 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 50 insertions(+) > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index 6f14de4..4fca526 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -87,6 +87,10 @@ extern bool is_vma_temporary_stack(struct vm_area_struct *vma); > > extern unsigned long transparent_hugepage_flags; > > +extern unsigned long thp_get_unmapped_area(struct file *filp, > + unsigned long addr, unsigned long len, unsigned long pgoff, > + unsigned long flags); > + > extern void prep_transhuge_page(struct page *page); > extern void free_transhuge_page(struct page *page); > > @@ -169,6 +173,9 @@ void put_huge_zero_page(void); > static inline void prep_transhuge_page(struct page *page) {} > > #define transparent_hugepage_flags 0UL > + > +#define thp_get_unmapped_area NULL Lets make this: static inline unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { return 0; } ...to get some type checking in the CONFIG_TRANSPARENT_HUGEPAGE=n case. -- 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