From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx136.postini.com [74.125.245.136]) by kanga.kvack.org (Postfix) with SMTP id 9D10D6B005A for ; Wed, 19 Sep 2012 05:12:54 -0400 (EDT) Received: by qcsd16 with SMTP id d16so748705qcs.14 for ; Wed, 19 Sep 2012 02:12:53 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20120918123331.6ca5833c.akpm@linux-foundation.org> References: <1347382036-18455-1-git-send-email-will.deacon@arm.com> <1347382036-18455-3-git-send-email-will.deacon@arm.com> <20120915133833.GA32398@linux-mips.org> <20120918123331.6ca5833c.akpm@linux-foundation.org> From: Catalin Marinas Date: Wed, 19 Sep 2012 10:12:28 +0100 Message-ID: Subject: Re: [PATCH 2/3] mm: thp: Fix the update_mmu_cache() last argument passing in mm/huge_memory.c Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Ralf Baechle , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mhocko@suse.cz, Steve Capper On 18 September 2012 20:33, Andrew Morton wrote: > On Sat, 15 Sep 2012 15:38:33 +0200 > Ralf Baechle wrote: >> On Tue, Sep 11, 2012 at 05:47:15PM +0100, Will Deacon wrote: >> > The update_mmu_cache() takes a pointer (to pte_t by default) as the last >> > argument but the huge_memory.c passes a pmd_t value. The patch changes >> > the argument to the pmd_t * pointer. >> > >> > Signed-off-by: Catalin Marinas >> > Signed-off-by: Steve Capper >> > Signed-off-by: Will Deacon >> > --- >> > mm/huge_memory.c | 6 +++--- >> > 1 files changed, 3 insertions(+), 3 deletions(-) >> > >> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> > index 57c4b93..4aa6d02 100644 >> > --- a/mm/huge_memory.c >> > +++ b/mm/huge_memory.c >> > @@ -934,7 +934,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, >> > entry = pmd_mkyoung(orig_pmd); >> > entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); >> > if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) >> > - update_mmu_cache(vma, address, entry); >> > + update_mmu_cache(vma, address, pmd); >> >> Documentation/cachetlb.txt will need an update as well. Currently it says: >> >> 5) void update_mmu_cache(struct vm_area_struct *vma, >> unsigned long address, pte_t *ptep) > > Yes please. Should we just use a generic (void *) for the last argument or force a cast in mm/huge_memory.c? Ralf's point is that transparent huge page code calls update_mmu_cache with a (pmd_t *) as the last argument. This could make sense for THP as it assumes that huge pages can only be created at the pmd level. But that's unlike mm/hugetlb.c which casts huge page types to pte_t, even though on ARM they are implemented at the pmd level. On ARM (with VIPT caches) update_mmu_cache() is empty like on x86, though a static inline rather than macro. -- Catalin -- 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