Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751428Ab3IPViQ (ORCPT ); Mon, 16 Sep 2013 17:38:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20266 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750968Ab3IPViM (ORCPT ); Mon, 16 Sep 2013 17:38:12 -0400 Date: Mon, 16 Sep 2013 17:37:40 -0400 From: Naoya Horiguchi To: "Aneesh Kumar K.V" Cc: linux-mm@kvack.org, Andrew Morton , Alex Thorlton , Mel Gorman , Andi Kleen , Michal Hocko , KOSAKI Motohiro , Rik van Riel , Andrea Arcangeli , kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Message-ID: <1379367460-zt1iacf9-mutt-n-horiguchi@ah.jp.nec.com> In-Reply-To: <878uywbzpt.fsf@linux.vnet.ibm.com> References: <1379117362-gwv3vrog-mutt-n-horiguchi@ah.jp.nec.com> <878uywbzpt.fsf@linux.vnet.ibm.com> Subject: Re: [PATCH v4] hugetlbfs: support split page table lock Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Mutt-Fcc: ~/Maildir/sent/ User-Agent: Mutt 1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1870 Lines: 46 On Mon, Sep 16, 2013 at 08:06:30PM +0530, Aneesh Kumar K.V wrote: > Naoya Horiguchi writes: > > > Hi, > > > > Kirill posted split_ptl patchset for thp today, so in this version > > I post only hugetlbfs part. I added Kconfig variables in following > > Kirill's patches (although without CONFIG_SPLIT_*_PTLOCK_CPUS.) > > > > This patch changes many lines, but all are in hugetlbfs specific code, > > so I think we can apply this independent of thp patches. > > ----- > > From: Naoya Horiguchi > > Date: Fri, 13 Sep 2013 18:12:30 -0400 > > Subject: [PATCH v4] hugetlbfs: support split page table lock > > > > Currently all of page table handling by hugetlbfs code are done under > > mm->page_table_lock. So when a process have many threads and they heavily > > access to the memory, lock contention happens and impacts the performance. > > > > This patch makes hugepage support split page table lock so that we use > > page->ptl of the leaf node of page table tree which is pte for normal pages > > but can be pmd and/or pud for hugepages of some architectures. > > > > ChangeLog v4: > > - introduce arch dependent macro ARCH_ENABLE_SPLIT_HUGETLB_PTLOCK > > (only defined for x86 for now) > > - rename USE_SPLIT_PTLOCKS_HUGETLB to USE_SPLIT_HUGETLB_PTLOCKS > > Can we have separate locking for THP and hugetlb ? I think yes, because thp code and hugetlbfs code are clearly separated and we can execute only one of them on the same vma. > Doesn't both require us to > use same locking when updating pmd ? I think no for the same reason. Thanks, Naoya Horiguchi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/