From 61f77eda9bbf0d2e922197ed2dcf88638a639ce5 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Wed, 11 Feb 2015 15:25:15 -0800 Subject: mm/hugetlb: reduce arch dependent code around follow_huge_* Currently we have many duplicates in definitions around follow_huge_addr(), follow_huge_pmd(), and follow_huge_pud(), so this patch tries to remove the m. The basic idea is to put the default implementation for these functions in mm/hugetlb.c as weak symbols (regardless of CONFIG_ARCH_WANT_GENERAL_HUGETL B), and to implement arch-specific code only when the arch needs it. For follow_huge_addr(), only powerpc and ia64 have their own implementation, and in all other architectures this function just returns ERR_PTR(-EINVAL). So this patch sets returning ERR_PTR(-EINVAL) as default. As for follow_huge_(pmd|pud)(), if (pmd|pud)_huge() is implemented to always return 0 in your architecture (like in ia64 or sparc,) it's never called (the callsite is optimized away) no matter how implemented it is. So in such architectures, we don't need arch-specific implementation. In some architecture (like mips, s390 and tile,) their current arch-specific follow_huge_(pmd|pud)() are effectively identical with the common code, so this patch lets these architecture use the common code. One exception is metag, where pmd_huge() could return non-zero but it expects follow_huge_pmd() to always return NULL. This means that we need arch-specific implementation which returns NULL. This behavior looks strange to me (because non-zero pmd_huge() implies that the architecture supports PMD-based hugepage, so follow_huge_pmd() can/should return some relevant value,) but that's beyond this cleanup patch, so let's keep it. Justification of non-trivial changes: - in s390, follow_huge_pmd() checks !MACHINE_HAS_HPAGE at first, and this patch removes the check. This is OK because we can assume MACHINE_HAS_HPAGE is true when follow_huge_pmd() can be called (note that pmd_huge() has the same check and always returns 0 for !MACHINE_HAS_HPAGE.) - in s390 and mips, we use HPAGE_MASK instead of PMD_MASK as done in common code. This patch forces these archs use PMD_MASK, but it's OK because they are identical in both archs. In s390, both of HPAGE_SHIFT and PMD_SHIFT are 20. In mips, HPAGE_SHIFT is defined as (PAGE_SHIFT + PAGE_SHIFT - 3) and PMD_SHIFT is define as (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3), but PTE_ORDER is always 0, so these are identical. Signed-off-by: Naoya Horiguchi Acked-by: Hugh Dickins Cc: James Hogan Cc: David Rientjes Cc: Mel Gorman Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Cc: Andrea Arcangeli Cc: Luiz Capitulino Cc: Nishanth Aravamudan Cc: Lee Schermerhorn Cc: Steve Capper Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/mm/hugetlbpage.c | 20 -------------------- 1 file changed, 20 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index 3c80d2e38f03..210ffede0153 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -192,12 +192,6 @@ int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) return 0; } -struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address, - int write) -{ - return ERR_PTR(-EINVAL); -} - int pmd_huge(pmd_t pmd) { if (!MACHINE_HAS_HPAGE) @@ -210,17 +204,3 @@ int pud_huge(pud_t pud) { return 0; } - -struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address, - pmd_t *pmdp, int write) -{ - struct page *page; - - if (!MACHINE_HAS_HPAGE) - return NULL; - - page = pmd_page(*pmdp); - if (page) - page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT); - return page; -} -- cgit v1.2.3 From d016bf7ece53b2b947bfd769e0842fd2feb7556b Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 11 Feb 2015 15:26:41 -0800 Subject: mm: make FIRST_USER_ADDRESS unsigned long on all archs LKP has triggered a compiler warning after my recent patch "mm: account pmd page tables to the process": mm/mmap.c: In function 'exit_mmap': >> mm/mmap.c:2857:2: warning: right shift count >= width of type [enabled by default] The code: > 2857 WARN_ON(mm_nr_pmds(mm) > 2858 round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> PUD_SHIFT); In this, on tile, we have FIRST_USER_ADDRESS defined as 0. round_up() has the same type -- int. PUD_SHIFT. I think the best way to fix it is to define FIRST_USER_ADDRESS as unsigned long. On every arch for consistency. Signed-off-by: Kirill A. Shutemov Reported-by: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index ffb1d8ce97ae..aabcd3f62d3b 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -99,7 +99,7 @@ extern unsigned long zero_page_mask; #endif /* CONFIG_64BIT */ #define PTRS_PER_PGD 2048 -#define FIRST_USER_ADDRESS 0 +#define FIRST_USER_ADDRESS 0UL #define pte_ERROR(e) \ printk("%s:%d: bad pte %p.\n", __FILE__, __LINE__, (void *) pte_val(e)) -- cgit v1.2.3 From a7b780750e1a1c7833812681e1f8fa30bbb06802 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Wed, 11 Feb 2015 15:27:23 -0800 Subject: mm: gup: use get_user_pages_unlocked within get_user_pages_fast This allows the get_user_pages_fast slow path to release the mmap_sem before blocking. Signed-off-by: Andrea Arcangeli Reviewed-by: Kirill A. Shutemov Cc: Andres Lagar-Cavilla Cc: Peter Feiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/mm/gup.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c index 639fce464008..5c586c78ca8d 100644 --- a/arch/s390/mm/gup.c +++ b/arch/s390/mm/gup.c @@ -235,10 +235,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, /* Try to get the remaining pages with get_user_pages */ start += nr << PAGE_SHIFT; pages += nr; - down_read(&mm->mmap_sem); - ret = get_user_pages(current, mm, start, - nr_pages - nr, write, 0, pages, NULL); - up_read(&mm->mmap_sem); + ret = get_user_pages_unlocked(current, mm, start, + nr_pages - nr, write, 0, pages); /* Have to be a bit careful with return values */ if (nr > 0) ret = (ret < 0) ? nr : ret + nr; -- cgit v1.2.3