From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f69.google.com (mail-pl0-f69.google.com [209.85.160.69]) by kanga.kvack.org (Postfix) with ESMTP id 372376B025F for ; Wed, 13 Dec 2017 08:07:06 -0500 (EST) Received: by mail-pl0-f69.google.com with SMTP id x1so1079131plb.2 for ; Wed, 13 Dec 2017 05:07:06 -0800 (PST) Received: from ozlabs.org (ozlabs.org. [103.22.144.67]) by mx.google.com with ESMTPS id w15si1329892plp.561.2017.12.13.05.07.04 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 13 Dec 2017 05:07:04 -0800 (PST) From: Michael Ellerman Subject: Re: [PATCH 1/2] mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct In-Reply-To: <20171210113715.GE20234@dhcp22.suse.cz> References: <151270384965.21215.2022156459463260344.stgit@dwillia2-desk3.amr.corp.intel.com> <151270385525.21215.16828596212056611775.stgit@dwillia2-desk3.amr.corp.intel.com> <20171210113715.GE20234@dhcp22.suse.cz> Date: Thu, 14 Dec 2017 00:07:01 +1100 Message-ID: <87o9n2aia2.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , Dan Williams Cc: akpm@linux-foundation.org, Jane Chu , linux-nvdimm@lists.01.org, Benjamin Herrenschmidt , linux-mm@kvack.org, Paul Mackerras Michal Hocko writes: > On Thu 07-12-17 19:30:55, Dan Williams wrote: >> When device-dax is operating in huge-page mode we want it to behave like >> hugetlbfs and report the MMU page mapping size that is being enforced by >> the vma. Similar to commit 31383c6865a5 "mm, hugetlbfs: introduce >> ->split() to vm_operations_struct" it would be messy to teach >> vma_mmu_pagesize() about device-dax page mapping sizes in the same >> (hstate) way that hugetlbfs communicates this attribute. Instead, these >> patches introduce a new ->pagesize() vm operation. >> >> Cc: Benjamin Herrenschmidt >> Cc: Paul Mackerras >> Cc: Michael Ellerman >> Reported-by: Jane Chu >> Signed-off-by: Dan Williams > > My build battery choked on the following > In file included from drivers/infiniband/core/umem_odp.c:41:0: > ./include/linux/hugetlb.h: In function 'vma_kernel_pagesize': > ./include/linux/hugetlb.h:262:32: error: dereferencing pointer to incomplete type > if (vma->vm_ops && vma->vm_ops->pagesize) > ^ > ./include/linux/hugetlb.h:263:21: error: dereferencing pointer to incomplete type > return vma->vm_ops->pagesize(vma); > > I thought that adding #include into linux/hugetlb.h would > be sufficient but then it failed for powerpc defconfig which overrides > vma_kernel_pagesize > In file included from ./include/linux/hugetlb.h:452:0, > from arch/powerpc/mm/hugetlbpage.c:14: > ./arch/powerpc/include/asm/hugetlb.h:131:26: error: redefinition of 'vma_mmu_pagesize' > #define vma_mmu_pagesize vma_mmu_pagesize > ^ > arch/powerpc/mm/hugetlbpage.c:563:15: note: in expansion of macro 'vma_mmu_pagesize' > unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) > ^ > In file included from arch/powerpc/mm/hugetlbpage.c:14:0: > ./include/linux/hugetlb.h:275:29: note: previous definition of 'vma_mmu_pagesize' was here > static inline unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) > > So it looks this needs something more laborous. This builds for me. cheers diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h index 14c9d44f355b..3cc6ca1bdaf2 100644 --- a/arch/powerpc/include/asm/hugetlb.h +++ b/arch/powerpc/include/asm/hugetlb.h @@ -123,6 +123,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr, * to override the version in mm/hugetlb.c */ #define vma_mmu_pagesize vma_mmu_pagesize +unsigned long vma_mmu_pagesize(struct vm_area_struct *vma); /* * If the arch doesn't supply something else, assume that hugepage diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index a9b9083c5e49..c6a2e577e842 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -568,10 +568,7 @@ unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) if (!radix_enabled()) return 1UL << mmu_psize_to_shift(psize); #endif - if (!is_vm_hugetlb_page(vma)) - return PAGE_SIZE; - - return huge_page_size(hstate_vma(vma)); + return vma_kernel_pagesize(vma); } static inline bool is_power_of_4(unsigned long x) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 6e3696c7b35a..fe7b74325856 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -394,10 +394,6 @@ static inline unsigned long huge_page_size(struct hstate *h) return (unsigned long)PAGE_SIZE << h->order; } -extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma); - -extern unsigned long vma_mmu_pagesize(struct vm_area_struct *vma); - static inline unsigned long huge_page_mask(struct hstate *h) { return h->mask; @@ -430,6 +426,30 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h) #include +/* + * Return the size of the pages allocated when backing a VMA. In the majority + * cases this will be same size as used by the page table entries. + */ +static inline unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->pagesize) + return vma->vm_ops->pagesize(vma); + return PAGE_SIZE; +} + +/* + * Return the page size being used by the MMU to back a VMA. In the majority + * of cases, the page size used by the kernel matches the MMU size. On + * architectures where it differs, an architecture-specific version of this + * function is required. + */ +#ifndef vma_mmu_pagesize +static inline unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) +{ + return vma_kernel_pagesize(vma); +} +#endif + #ifndef arch_make_huge_pte static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma, struct page *page, int writable) @@ -533,8 +553,6 @@ struct hstate {}; #define page_hstate(page) NULL #define huge_page_size(h) PAGE_SIZE #define huge_page_mask(h) PAGE_MASK -#define vma_kernel_pagesize(v) PAGE_SIZE -#define vma_mmu_pagesize(v) PAGE_SIZE #define huge_page_order(h) 0 #define huge_page_shift(h) PAGE_SHIFT static inline bool hstate_is_gigantic(struct hstate *h) diff --git a/include/linux/mm.h b/include/linux/mm.h index 7661156552d3..1933499f896d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -383,6 +383,7 @@ struct vm_operations_struct { int (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size); void (*map_pages)(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff); + unsigned long (*pagesize)(struct vm_area_struct * area); /* notification that a previously read-only page is about to become * writable, if an error is returned it will cause a SIGBUS */ diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4137fb67cd79..7c1c45bb3d08 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -629,36 +629,6 @@ pgoff_t linear_hugepage_index(struct vm_area_struct *vma, } EXPORT_SYMBOL_GPL(linear_hugepage_index); -/* - * Return the size of the pages allocated when backing a VMA. In the majority - * cases this will be same size as used by the page table entries. - */ -unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) -{ - struct hstate *hstate; - - if (!is_vm_hugetlb_page(vma)) - return PAGE_SIZE; - - hstate = hstate_vma(vma); - - return 1UL << huge_page_shift(hstate); -} -EXPORT_SYMBOL_GPL(vma_kernel_pagesize); - -/* - * Return the page size being used by the MMU to back a VMA. In the majority - * of cases, the page size used by the kernel matches the MMU size. On - * architectures where it differs, an architecture-specific version of this - * function is required. - */ -#ifndef vma_mmu_pagesize -unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) -{ - return vma_kernel_pagesize(vma); -} -#endif - /* * Flags for MAP_PRIVATE reservations. These are stored in the bottom * bits of the reservation map pointer, which are always clear due to @@ -3142,6 +3112,13 @@ static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr) return 0; } +static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma) +{ + struct hstate *hstate = hstate_vma(vma); + + return 1UL << huge_page_shift(hstate); +} + /* * We cannot handle pagefaults against hugetlb pages at all. They cause * handle_mm_fault() to try to instantiate regular-sized pages in the @@ -3159,6 +3136,7 @@ const struct vm_operations_struct hugetlb_vm_ops = { .open = hugetlb_vm_op_open, .close = hugetlb_vm_op_close, .split = hugetlb_vm_op_split, + .pagesize = hugetlb_vm_op_pagesize, }; static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, -- 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