From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 29 Jan 2016 12:01:31 +0200 From: "Kirill A. Shutemov" To: Mike Kravetz Cc: "Aneesh Kumar K.V" , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [LSF/MM ATTEND] Huge Page Futures Message-ID: <20160129100131.GA10918@node.shutemov.name> References: <56A580F8.4060301@oracle.com> <87bn85ycbh.fsf@linux.vnet.ibm.com> <56AA6BE1.2050809@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56AA6BE1.2050809@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: On Thu, Jan 28, 2016 at 11:28:33AM -0800, Mike Kravetz wrote: > On 01/28/2016 07:05 AM, Aneesh Kumar K.V wrote: > > Mike Kravetz writes: > > > >> In a search of the archives, it appears huge page support in one form or > >> another has been a discussion topic in almost every LSF/MM gathering. Based > >> on patches submitted this past year, huge pages is still an area of active > >> development. And, it appears this level of activity will continue in the > >> coming year. > >> > >> I propose a "Huge Page Futures" session to discuss large works in progress > >> as well as work people are considering for 2016. Areas of discussion would > >> minimally include: > >> > >> - Krill Shutemov's THP new refcounting code and the push for huge page > >> support in the page cache. > > > > I am also interested in this discussion. We had some nice challenge > > w.r.t to powerpc implementation of THP. > > > >> > >> - Matt Wilcox's huge page support in DAX enabled filesystems, but perhaps > >> more interesting is the desire for supporting PUD pages. This seems to > >> beg the question of supporting transparent PUD pages elsewhere. > >> > > > > I am also looking at switching powerpc hugetlbfs to GENERAL_HUGETLB. To > > support 16GB pages I would need hugepage at PUD/PGD. Can you elaborate > > why supporting huge PUD page is a challenge ? > > For hugetlbfs it should not be an issue. However, page fault handling for > hugetlbfs is already a special case today. Is that what you were asking? > > Matt's work adds THP for PUD sized huge pages to DAX mappings. The thought > that popped into my head is "Does it make sense to try and expand THP for > PUD sized pages elsewhere?". Perhaps that is nonsense and a silly question > to ask. I don't think it has much sense on x86-64. But if an architecture has more reasonable page size on PUD level, who knows... -- Kirill A. Shutemov -- 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