From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id 787056B0003 for ; Wed, 24 Oct 2018 09:56:42 -0400 (EDT) Received: by mail-pf1-f198.google.com with SMTP id j9-v6so1243338pfn.20 for ; Wed, 24 Oct 2018 06:56:42 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id n38-v6si4891567pgm.418.2018.10.24.06.56.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Oct 2018 06:56:41 -0700 (PDT) Date: Wed, 24 Oct 2018 15:56:39 +0200 From: Michal Hocko Subject: Re: [PATCH V3 3/5] mm/hugetlb: Enable arch specific huge page size support for migration Message-ID: <20181024135639.GH18839@dhcp22.suse.cz> References: <1540299721-26484-1-git-send-email-anshuman.khandual@arm.com> <1540299721-26484-4-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1540299721-26484-4-git-send-email-anshuman.khandual@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, suzuki.poulose@arm.com, punit.agrawal@arm.com, will.deacon@arm.com, Steven.Price@arm.com, steve.capper@arm.com, catalin.marinas@arm.com, akpm@linux-foundation.org, mike.kravetz@oracle.com, n-horiguchi@ah.jp.nec.com On Tue 23-10-18 18:31:59, Anshuman Khandual wrote: > Architectures like arm64 have HugeTLB page sizes which are different than > generic sizes at PMD, PUD, PGD level and implemented via contiguous bits. > At present these special size HugeTLB pages cannot be identified through > macros like (PMD|PUD|PGDIR)_SHIFT and hence chosen not be migrated. > > Enabling migration support for these special HugeTLB page sizes along with > the generic ones (PMD|PUD|PGD) would require identifying all of them on a > given platform. A platform specific hook can precisely enumerate all huge > page sizes supported for migration. Instead of comparing against standard > huge page orders let hugetlb_migration_support() function call a platform > hook arch_hugetlb_migration_support(). Default definition for the platform > hook maintains existing semantics which checks standard huge page order. > But an architecture can choose to override the default and provide support > for a comprehensive set of huge page sizes. > > Reviewed-by: Naoya Horiguchi > Signed-off-by: Anshuman Khandual Acked-by: Michal Hocko > --- > include/linux/hugetlb.h | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 70bcd89..4cc3871 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -493,18 +493,29 @@ static inline pgoff_t basepage_index(struct page *page) > extern int dissolve_free_huge_page(struct page *page); > extern int dissolve_free_huge_pages(unsigned long start_pfn, > unsigned long end_pfn); > -static inline bool hugepage_migration_supported(struct hstate *h) > -{ > + > #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION > +#ifndef arch_hugetlb_migration_supported > +static inline bool arch_hugetlb_migration_supported(struct hstate *h) > +{ > if ((huge_page_shift(h) == PMD_SHIFT) || > (huge_page_shift(h) == PUD_SHIFT) || > (huge_page_shift(h) == PGDIR_SHIFT)) > return true; > else > return false; > +} > +#endif > #else > +static inline bool arch_hugetlb_migration_supported(struct hstate *h) > +{ > return false; > +} > #endif > + > +static inline bool hugepage_migration_supported(struct hstate *h) > +{ > + return arch_hugetlb_migration_supported(h); > } > > /* > -- > 2.7.4 -- Michal Hocko SUSE Labs