* [PATCH v3 mm 1/2] mm: Define pte_index as macro for x86 @ 2020-02-28 5:47 Arjun Roy 2020-02-28 5:47 ` [PATCH v3 mm 2/2] mm: vm_insert_pages() checks if pte_index defined Arjun Roy 0 siblings, 1 reply; 4+ messages in thread From: Arjun Roy @ 2020-02-28 5:47 UTC (permalink / raw) To: davem, akpm, linux-mm; +Cc: arjunroy, soheil, edumazet, sfr, geert From: Arjun Roy <arjunroy@google.com> pte_index() is either defined as a macro (e.g. sparc64) or as an inlined function (e.g. x86). vm_insert_pages() depends on pte_index but it is not defined on all platforms (e.g. m68k). To fix compilation of vm_insert_pages() on architectures not providing pte_index(), we perform the following fix: 0. For platforms where it is meaningful, and defined as a macro, no change is needed. 1. For platforms where it is meaningful and defined as an inlined function, and we want to use it with vm_insert_pages(), we define a degenerate macro of the form: #define pte_index pte_index 2. vm_insert_pages() checks for the existence of a pte_index macro definition. If found, it implements a batched insert. If not found, it devolves to calling vm_insert_page() in a loop. This patch implements step 1 for x86. v3 of this patch fixes a compilation warning for an unused method. v2 of this patch moved a macro definition to a more readable location. Signed-off-by: Arjun Roy <arjunroy@google.com> --- arch/x86/include/asm/pgtable.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 7e118660bbd9..d9925b10e326 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -828,7 +828,10 @@ static inline unsigned long pmd_index(unsigned long address) * * this function returns the index of the entry in the pte page which would * control the given virtual address + * + * Also define macro so we can test if pte_index is defined for arch. */ +#define pte_index pte_index static inline unsigned long pte_index(unsigned long address) { return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); -- 2.25.1.481.gfbce0eb801-goog ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3 mm 2/2] mm: vm_insert_pages() checks if pte_index defined. 2020-02-28 5:47 [PATCH v3 mm 1/2] mm: Define pte_index as macro for x86 Arjun Roy @ 2020-02-28 5:47 ` Arjun Roy 2020-02-28 13:38 ` Jason Gunthorpe 0 siblings, 1 reply; 4+ messages in thread From: Arjun Roy @ 2020-02-28 5:47 UTC (permalink / raw) To: davem, akpm, linux-mm; +Cc: arjunroy, soheil, edumazet, sfr, geert From: Arjun Roy <arjunroy@google.com> pte_index() is either defined as a macro (e.g. sparc64) or as an inlined function (e.g. x86). vm_insert_pages() depends on pte_index but it is not defined on all platforms (e.g. m68k). To fix compilation of vm_insert_pages() on architectures not providing pte_index(), we perform the following fix: 0. For platforms where it is meaningful, and defined as a macro, no change is needed. 1. For platforms where it is meaningful and defined as an inlined function, and we want to use it with vm_insert_pages(), we define a degenerate macro of the form: #define pte_index pte_index 2. vm_insert_pages() checks for the existence of a pte_index macro definition. If found, it implements a batched insert. If not found, it devolves to calling vm_insert_page() in a loop. This patch implements step 2. v3 of this patch fixes a compilation warning for an unused method. v2 of this patch moved a macro definition to a more readable location. Signed-off-by: Arjun Roy <arjunroy@google.com> --- mm/memory.c | 41 ++++++++++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 13 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index d6f834f7d145..47b28fcc73c2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1460,18 +1460,6 @@ static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte, return 0; } -static int insert_page_in_batch_locked(struct mm_struct *mm, pmd_t *pmd, - unsigned long addr, struct page *page, pgprot_t prot) -{ - int err; - - if (!page_count(page)) - return -EINVAL; - err = validate_page_before_insert(page); - return err ? err : insert_page_into_pte_locked( - mm, pte_offset_map(pmd, addr), addr, page, prot); -} - /* * This is the old fallback for page remapping. * @@ -1500,8 +1488,21 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr, return retval; } +#ifdef pte_index +static int insert_page_in_batch_locked(struct mm_struct *mm, pmd_t *pmd, + unsigned long addr, struct page *page, pgprot_t prot) +{ + int err; + + if (!page_count(page)) + return -EINVAL; + err = validate_page_before_insert(page); + return err ? err : insert_page_into_pte_locked( + mm, pte_offset_map(pmd, addr), addr, page, prot); +} + /* insert_pages() amortizes the cost of spinlock operations - * when inserting pages in a loop. + * when inserting pages in a loop. Arch *must* define pte_index. */ static int insert_pages(struct vm_area_struct *vma, unsigned long addr, struct page **pages, unsigned long *num, pgprot_t prot) @@ -1556,6 +1557,7 @@ static int insert_pages(struct vm_area_struct *vma, unsigned long addr, *num = remaining_pages_total; return ret; } +#endif /* ifdef pte_index */ /** * vm_insert_pages - insert multiple pages into user vma, batching the pmd lock. @@ -1575,6 +1577,7 @@ static int insert_pages(struct vm_area_struct *vma, unsigned long addr, int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, struct page **pages, unsigned long *num) { +#ifdef pte_index const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1; if (addr < vma->vm_start || end_addr >= vma->vm_end) @@ -1586,6 +1589,18 @@ int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, } /* Defer page refcount checking till we're about to map that page. */ return insert_pages(vma, addr, pages, num, vma->vm_page_prot); +#else + unsigned long idx = 0, pgcount = *num; + int err; + + for (; idx < pgcount; ++idx) { + err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); + if (err) + break; + } + *num = pgcount - idx; + return err; +#endif /* ifdef pte_index */ } EXPORT_SYMBOL(vm_insert_pages); -- 2.25.1.481.gfbce0eb801-goog ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3 mm 2/2] mm: vm_insert_pages() checks if pte_index defined. 2020-02-28 5:47 ` [PATCH v3 mm 2/2] mm: vm_insert_pages() checks if pte_index defined Arjun Roy @ 2020-02-28 13:38 ` Jason Gunthorpe 2020-02-28 17:22 ` Soheil Hassas Yeganeh 0 siblings, 1 reply; 4+ messages in thread From: Jason Gunthorpe @ 2020-02-28 13:38 UTC (permalink / raw) To: Arjun Roy; +Cc: davem, akpm, linux-mm, arjunroy, soheil, edumazet, sfr, geert On Thu, Feb 27, 2020 at 09:47:14PM -0800, Arjun Roy wrote: > diff --git a/mm/memory.c b/mm/memory.c > index d6f834f7d145..47b28fcc73c2 100644 > +++ b/mm/memory.c > @@ -1460,18 +1460,6 @@ static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte, > return 0; > } > > -static int insert_page_in_batch_locked(struct mm_struct *mm, pmd_t *pmd, > - unsigned long addr, struct page *page, pgprot_t prot) > -{ > - int err; > - > - if (!page_count(page)) > - return -EINVAL; > - err = validate_page_before_insert(page); > - return err ? err : insert_page_into_pte_locked( > - mm, pte_offset_map(pmd, addr), addr, page, prot); > -} > - > /* > * This is the old fallback for page remapping. > * > @@ -1500,8 +1488,21 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr, > return retval; > } > > +#ifdef pte_index It seems a bit weird like this, don't we usually do this kind of stuff with some CONFIG_ARCH_HAS_XX thing? IMHO all arches should implement pte_index as the static inline, that has been the general direction lately. Jason ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3 mm 2/2] mm: vm_insert_pages() checks if pte_index defined. 2020-02-28 13:38 ` Jason Gunthorpe @ 2020-02-28 17:22 ` Soheil Hassas Yeganeh 0 siblings, 0 replies; 4+ messages in thread From: Soheil Hassas Yeganeh @ 2020-02-28 17:22 UTC (permalink / raw) To: Jason Gunthorpe Cc: Arjun Roy, David Miller, akpm, linux-mm, Arjun Roy, Eric Dumazet, Stephen Rothwell, geert On Fri, Feb 28, 2020 at 8:38 AM Jason Gunthorpe <jgg@ziepe.ca> wrote: > > On Thu, Feb 27, 2020 at 09:47:14PM -0800, Arjun Roy wrote: > > diff --git a/mm/memory.c b/mm/memory.c > > index d6f834f7d145..47b28fcc73c2 100644 > > +++ b/mm/memory.c > > @@ -1460,18 +1460,6 @@ static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte, > > return 0; > > } > > > > -static int insert_page_in_batch_locked(struct mm_struct *mm, pmd_t *pmd, > > - unsigned long addr, struct page *page, pgprot_t prot) > > -{ > > - int err; > > - > > - if (!page_count(page)) > > - return -EINVAL; > > - err = validate_page_before_insert(page); > > - return err ? err : insert_page_into_pte_locked( > > - mm, pte_offset_map(pmd, addr), addr, page, prot); > > -} > > - > > /* > > * This is the old fallback for page remapping. > > * > > @@ -1500,8 +1488,21 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr, > > return retval; > > } > > > > +#ifdef pte_index > > It seems a bit weird like this, don't we usually do this kind of stuff > with some CONFIG_ARCH_HAS_XX thing? > > IMHO all arches should implement pte_index as the static inline, that > has been the general direction lately. Based on a comment from Stephen Rothwell, we found out that "static inline" functions are only used in tile and x86. That's why Arjun opted for this method to create a smaller patch-series to fix the build breakage. Thanks, Soheil > Jason ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-02-28 17:23 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-02-28 5:47 [PATCH v3 mm 1/2] mm: Define pte_index as macro for x86 Arjun Roy 2020-02-28 5:47 ` [PATCH v3 mm 2/2] mm: vm_insert_pages() checks if pte_index defined Arjun Roy 2020-02-28 13:38 ` Jason Gunthorpe 2020-02-28 17:22 ` Soheil Hassas Yeganeh
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