From: Michal Hocko <mhocko@kernel.org> To: Anshuman Khandual <anshuman.khandual@arm.com> 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, catalin.marinas@arm.com, mike.kravetz@oracle.com, n-horiguchi@ah.jp.nec.com Subject: Re: [PATCH 1/4] mm/hugetlb: Enable PUD level huge page migration Date: Wed, 10 Oct 2018 11:39:07 +0200 [thread overview] Message-ID: <20181010093907.GF5873@dhcp22.suse.cz> (raw) In-Reply-To: <b722d14e-d14f-f45d-5722-685d4f21f6e4@arm.com> On Wed 10-10-18 08:39:22, Anshuman Khandual wrote: [...] > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 9df1d59..4bcbf1e 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -504,6 +504,16 @@ static inline bool hugepage_migration_supported(struct hstate *h) > return arch_hugetlb_migration_supported(h); > } > > +static inline bool hugepage_movable_supported(struct hstate *h) > +{ > + if (!hugepage_migration_supported(h)) --> calls arch override restricting the set > + return false; > + > + if (hstate_is_gigantic(h) --------> restricts the set further > + return false; > + return true; > +} > + > static inline spinlock_t *huge_pte_lockptr(struct hstate *h, > struct mm_struct *mm, pte_t *pte) > { > @@ -600,6 +610,11 @@ static inline bool hugepage_migration_supported(struct hstate *h) > return false; > } > > +static inline bool hugepage_movable_supported(struct hstate *h) > +{ > + return false; > +} > + > static inline spinlock_t *huge_pte_lockptr(struct hstate *h, > struct mm_struct *mm, pte_t *pte) > { > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 3c21775..a5a111d 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -919,7 +919,7 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, > /* Movability of hugepages depends on migration support. */ > static inline gfp_t htlb_alloc_mask(struct hstate *h) > { > - if (hugepage_migration_supported(h)) > + if (hugepage_movable_supported(h)) > return GFP_HIGHUSER_MOVABLE; > else > return GFP_HIGHUSER; Exactly what I've had in mind. It would be great to have a comment in hugepage_movable_supported to explain why we are not supporting giga pages even though they are migrateable and why we need that distinction. > The above patch is in addition to the following later patch in the series. [...] > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 9c1b77f..9df1d59 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -479,18 +479,29 @@ 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); > } Yes making hugepage_migration_supported to have an arch override is definitely the right thing to do. Whether the above approach rather than a weak symbol is better is a matter of taste and I do not feel strongly about that. -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: mhocko@kernel.org (Michal Hocko) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/4] mm/hugetlb: Enable PUD level huge page migration Date: Wed, 10 Oct 2018 11:39:07 +0200 [thread overview] Message-ID: <20181010093907.GF5873@dhcp22.suse.cz> (raw) In-Reply-To: <b722d14e-d14f-f45d-5722-685d4f21f6e4@arm.com> On Wed 10-10-18 08:39:22, Anshuman Khandual wrote: [...] > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 9df1d59..4bcbf1e 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -504,6 +504,16 @@ static inline bool hugepage_migration_supported(struct hstate *h) > return arch_hugetlb_migration_supported(h); > } > > +static inline bool hugepage_movable_supported(struct hstate *h) > +{ > + if (!hugepage_migration_supported(h)) --> calls arch override restricting the set > + return false; > + > + if (hstate_is_gigantic(h) --------> restricts the set further > + return false; > + return true; > +} > + > static inline spinlock_t *huge_pte_lockptr(struct hstate *h, > struct mm_struct *mm, pte_t *pte) > { > @@ -600,6 +610,11 @@ static inline bool hugepage_migration_supported(struct hstate *h) > return false; > } > > +static inline bool hugepage_movable_supported(struct hstate *h) > +{ > + return false; > +} > + > static inline spinlock_t *huge_pte_lockptr(struct hstate *h, > struct mm_struct *mm, pte_t *pte) > { > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 3c21775..a5a111d 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -919,7 +919,7 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, > /* Movability of hugepages depends on migration support. */ > static inline gfp_t htlb_alloc_mask(struct hstate *h) > { > - if (hugepage_migration_supported(h)) > + if (hugepage_movable_supported(h)) > return GFP_HIGHUSER_MOVABLE; > else > return GFP_HIGHUSER; Exactly what I've had in mind. It would be great to have a comment in hugepage_movable_supported to explain why we are not supporting giga pages even though they are migrateable and why we need that distinction. > The above patch is in addition to the following later patch in the series. [...] > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 9c1b77f..9df1d59 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -479,18 +479,29 @@ 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); > } Yes making hugepage_migration_supported to have an arch override is definitely the right thing to do. Whether the above approach rather than a weak symbol is better is a matter of taste and I do not feel strongly about that. -- Michal Hocko SUSE Labs
next prev parent reply other threads:[~2018-10-10 9:39 UTC|newest] Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-02 12:15 [PATCH 0/4] arm64/mm: Enable HugeTLB migration Anshuman Khandual 2018-10-02 12:15 ` Anshuman Khandual 2018-10-02 12:15 ` [PATCH 1/4] mm/hugetlb: Enable PUD level huge page migration Anshuman Khandual 2018-10-02 12:15 ` Anshuman Khandual 2018-10-02 12:38 ` Suzuki K Poulose 2018-10-02 12:38 ` Suzuki K Poulose 2018-10-02 12:56 ` Anshuman Khandual 2018-10-02 12:56 ` Anshuman Khandual 2018-10-02 12:56 ` Anshuman Khandual 2018-10-03 10:22 ` Suzuki K Poulose 2018-10-03 10:22 ` Suzuki K Poulose 2018-10-03 10:22 ` Suzuki K Poulose 2018-10-03 11:10 ` Anshuman Khandual 2018-10-03 11:10 ` Anshuman Khandual 2018-10-03 11:10 ` Anshuman Khandual 2018-10-03 11:17 ` Suzuki K Poulose 2018-10-03 11:17 ` Suzuki K Poulose 2018-10-03 11:17 ` Suzuki K Poulose 2018-10-03 11:27 ` Michal Hocko 2018-10-03 11:27 ` Michal Hocko 2018-10-02 12:39 ` Michal Hocko 2018-10-02 12:39 ` Michal Hocko 2018-10-03 2:16 ` Anshuman Khandual 2018-10-03 2:16 ` Anshuman Khandual 2018-10-03 6:58 ` Michal Hocko 2018-10-03 6:58 ` Michal Hocko 2018-10-03 9:58 ` Anshuman Khandual 2018-10-03 9:58 ` Anshuman Khandual 2018-10-03 10:59 ` Michal Hocko 2018-10-03 10:59 ` Michal Hocko 2018-10-03 11:37 ` Anshuman Khandual 2018-10-03 11:37 ` Anshuman Khandual 2018-10-03 11:48 ` Michal Hocko 2018-10-03 11:48 ` Michal Hocko 2018-10-03 13:06 ` Anshuman Khandual 2018-10-03 13:06 ` Anshuman Khandual 2018-10-03 13:36 ` Michal Hocko 2018-10-03 13:36 ` Michal Hocko 2018-10-05 7:34 ` Anshuman Khandual 2018-10-05 7:34 ` Anshuman Khandual 2018-10-09 14:14 ` Michal Hocko 2018-10-09 14:14 ` Michal Hocko 2018-10-10 3:09 ` Anshuman Khandual 2018-10-10 3:09 ` Anshuman Khandual 2018-10-10 9:39 ` Michal Hocko [this message] 2018-10-10 9:39 ` Michal Hocko 2018-10-11 3:16 ` Anshuman Khandual 2018-10-11 3:16 ` Anshuman Khandual 2018-10-02 12:15 ` [PATCH 2/4] mm/hugetlb: Enable arch specific huge page size support for migration Anshuman Khandual 2018-10-02 12:15 ` Anshuman Khandual 2018-10-02 12:15 ` [PATCH 3/4] arm64/mm: Enable HugeTLB migration Anshuman Khandual 2018-10-02 12:15 ` Anshuman Khandual 2018-10-02 12:15 ` [PATCH 4/4] arm64/mm: Enable HugeTLB migration for contiguous bit HugeTLB pages Anshuman Khandual 2018-10-02 12:15 ` Anshuman Khandual
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