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Rao" , Juergen Gross , Boris Ostrovsky , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Alexander Viro , Christian Brauner Subject: [PATCH v1 2/3] mm/hugetlb: enforce that PMD PT sharing has split PMD PT locks Date: Fri, 26 Jul 2024 17:07:27 +0200 Message-ID: <20240726150728.3159964-3-david@redhat.com> In-Reply-To: <20240726150728.3159964-1-david@redhat.com> References: <20240726150728.3159964-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Content-Type: text/plain; charset="utf-8" Sharing page tables between processes but falling back to per-MM page table locks cannot possibly work. So, let's make sure that we do have split PMD locks by adding a new Kconfig option and letting that depend on CONFIG_SPLIT_PMD_PTLOCKS. Signed-off-by: David Hildenbrand Acked-by: Mike Rapoport (Microsoft) --- fs/Kconfig | 4 ++++ include/linux/hugetlb.h | 5 ++--- mm/hugetlb.c | 8 ++++---- 3 files changed, 10 insertions(+), 7 deletions(-) diff --git a/fs/Kconfig b/fs/Kconfig index a46b0cbc4d8f6..0e4efec1d92e6 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -288,6 +288,10 @@ config HUGETLB_PAGE_OPTIMIZE_VMEMMAP depends on ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP depends on SPARSEMEM_VMEMMAP =20 +config HUGETLB_PMD_PAGE_TABLE_SHARING + def_bool HUGETLB_PAGE + depends on ARCH_WANT_HUGE_PMD_SHARE && SPLIT_PMD_PTLOCKS + config ARCH_HAS_GIGANTIC_PAGE bool =20 diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index da800e56fe590..4d2f3224ff027 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -1243,7 +1243,7 @@ static inline __init void hugetlb_cma_reserve(int ord= er) } #endif =20 -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING static inline bool hugetlb_pmd_shared(pte_t *pte) { return page_count(virt_to_page(pte)) > 1; @@ -1279,8 +1279,7 @@ bool __vma_private_lock(struct vm_area_struct *vma); static inline pte_t * hugetlb_walk(struct vm_area_struct *vma, unsigned long addr, unsigned long= sz) { -#if defined(CONFIG_HUGETLB_PAGE) && \ - defined(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) && defined(CONFIG_LOCKDEP) +#if defined(CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING) && defined(CONFIG_LOCKD= EP) struct hugetlb_vma_lock *vma_lock =3D vma->vm_private_data; =20 /* diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0858a18272073..c4d94e122c41f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -7211,7 +7211,7 @@ long hugetlb_unreserve_pages(struct inode *inode, lon= g start, long end, return 0; } =20 -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING static unsigned long page_table_shareable(struct vm_area_struct *svma, struct vm_area_struct *vma, unsigned long addr, pgoff_t idx) @@ -7373,7 +7373,7 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_= area_struct *vma, return 1; } =20 -#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ +#else /* !CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ =20 pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pud_t *pud) @@ -7396,7 +7396,7 @@ bool want_pmd_share(struct vm_area_struct *vma, unsig= ned long addr) { return false; } -#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ +#endif /* CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ =20 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, @@ -7494,7 +7494,7 @@ unsigned long hugetlb_mask_last_page(struct hstate *h) /* See description above. Architectures can provide their own version. */ __weak unsigned long hugetlb_mask_last_page(struct hstate *h) { -#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING if (huge_page_size(h) =3D=3D PMD_SIZE) return PUD_SIZE - PMD_SIZE; #endif --=20 2.45.2