Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751810AbbH0Q44 (ORCPT ); Thu, 27 Aug 2015 12:56:56 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:36307 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751000AbbH0Q4y (ORCPT ); Thu, 27 Aug 2015 12:56:54 -0400 Subject: Re: [PATCH 04/11] ARCv2: mm: THP support To: "Kirill A. Shutemov" References: <1440666194-21478-1-git-send-email-vgupta@synopsys.com> <1440666194-21478-5-git-send-email-vgupta@synopsys.com> <20150827153254.GA21103@node.dhcp.inet.fi> Cc: Andrew Morton , "Aneesh Kumar K.V" , "Kirill A. Shutemov" , Mel Gorman , Matthew Wilcox , Minchan Kim , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, arc-linux-dev@synopsys.com From: Vineet Gupta Organization: Synopsys Message-ID: <55DF414C.6070601@synopsys.com> Date: Thu, 27 Aug 2015 22:26:44 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150827153254.GA21103@node.dhcp.inet.fi> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1366 Lines: 37 On Thursday 27 August 2015 09:02 PM, Kirill A. Shutemov wrote: > On Thu, Aug 27, 2015 at 02:33:07PM +0530, Vineet Gupta wrote: >> > +pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) >> > +{ >> > + struct list_head *lh; >> > + pgtable_t pgtable; >> > + pte_t *ptep; >> > + >> > + assert_spin_locked(&mm->page_table_lock); >> > + >> > + pgtable = pmd_huge_pte(mm, pmdp); >> > + lh = (struct list_head *) pgtable; >> > + if (list_empty(lh)) >> > + pmd_huge_pte(mm, pmdp) = (pgtable_t) NULL; >> > + else { >> > + pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next; >> > + list_del(lh); >> > + } > Side question: why pgtable_t is unsigned long on ARC and not struct page * > or pte_t *, like on other archs? We could avoid these casts. This goes back how I did this for ARC long back to avoid page_address() calls in general case. e.g. pte_alloc_one(), pmd_populate(), pte_free()... all needed to convert struct page to unsigned long. It was micro-optimization of sorts, but served us well. I could perhaps see try making it pte *, that will certainly remove a bunch of other casts as well. -Vineet -- 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/