From ded22e7a52e04f0aed854a55adadaf3090a065e2 Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Wed, 20 Feb 2013 13:14:08 +1100 Subject: [PATCH] mm: directly use __mlock_vma_pages_range() in find_extend_vma() In find_extend_vma(), we don't need mlock_vma_pages_range() to verify the vma type - we know we're working with a stack. So, we can call directly into __mlock_vma_pages_range(), and remove the last make_pages_present() call site. Note that we don't use mm_populate() here, so we can't release the mmap_sem while allocating new stack pages. This is deemed acceptable, because the stack vmas grow by a bounded number of pages at a time, and these are anon pages so we don't have to read from disk to populate them. Signed-off-by: Michel Lespinasse Acked-by: Rik van Riel Tested-by: Andy Lutomirski Cc: Greg Ungerer Cc: David Howells Signed-off-by: Andrew Morton --- include/linux/mm.h | 1 - mm/internal.h | 4 ++-- mm/memory.c | 24 ------------------- mm/mlock.c | 57 +++------------------------------------------- mm/mmap.c | 10 ++++---- 5 files changed, 9 insertions(+), 87 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index bca956e58715..a4f7769769fe 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1037,7 +1037,6 @@ static inline int fixup_user_fault(struct task_struct *tsk, } #endif -extern int make_pages_present(unsigned long addr, unsigned long end); extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write); diff --git a/mm/internal.h b/mm/internal.h index 9ba21100ebf3..1c0c4cc0fcf7 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -162,8 +162,8 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, struct rb_node *rb_parent); #ifdef CONFIG_MMU -extern long mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end); +extern long __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end, int *nonblocking); extern void munlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end); static inline void munlock_vma_pages_all(struct vm_area_struct *vma) diff --git a/mm/memory.c b/mm/memory.c index 569558810b90..5323be690191 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3824,30 +3824,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) } #endif /* __PAGETABLE_PMD_FOLDED */ -int make_pages_present(unsigned long addr, unsigned long end) -{ - int ret, len, write; - struct vm_area_struct * vma; - - vma = find_vma(current->mm, addr); - if (!vma) - return -ENOMEM; - /* - * We want to touch writable mappings with a write fault in order - * to break COW, except for shared mappings because these don't COW - * and we would not want to dirty them for nothing. - */ - write = (vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE; - BUG_ON(addr >= end); - BUG_ON(end > vma->vm_end); - len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; - ret = get_user_pages(current, current->mm, addr, - len, write, 0, NULL, NULL); - if (ret < 0) - return ret; - return ret == len ? 0 : -EFAULT; -} - #if !defined(__HAVE_ARCH_GATE_AREA) #if defined(AT_SYSINFO_EHDR) diff --git a/mm/mlock.c b/mm/mlock.c index a296a49865df..569400a5d079 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -155,9 +155,8 @@ void munlock_vma_page(struct page *page) * * vma->vm_mm->mmap_sem must be held for at least read. */ -static long __mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end, - int *nonblocking) +long __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end, int *nonblocking) { struct mm_struct *mm = vma->vm_mm; unsigned long addr = start; @@ -202,56 +201,6 @@ static int __mlock_posix_error_return(long retval) return retval; } -/** - * mlock_vma_pages_range() - mlock pages in specified vma range. - * @vma - the vma containing the specfied address range - * @start - starting address in @vma to mlock - * @end - end address [+1] in @vma to mlock - * - * For mmap()/mremap()/expansion of mlocked vma. - * - * return 0 on success for "normal" vmas. - * - * return number of pages [> 0] to be removed from locked_vm on success - * of "special" vmas. - */ -long mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) -{ - int nr_pages = (end - start) / PAGE_SIZE; - BUG_ON(!(vma->vm_flags & VM_LOCKED)); - - /* - * filter unlockable vmas - */ - if (vma->vm_flags & (VM_IO | VM_PFNMAP)) - goto no_mlock; - - if (!((vma->vm_flags & VM_DONTEXPAND) || - is_vm_hugetlb_page(vma) || - vma == get_gate_vma(current->mm))) { - - __mlock_vma_pages_range(vma, start, end, NULL); - - /* Hide errors from mmap() and other callers */ - return 0; - } - - /* - * User mapped kernel pages or huge pages: - * make these pages present to populate the ptes, but - * fall thru' to reset VM_LOCKED--no need to unlock, and - * return nr_pages so these don't get counted against task's - * locked limit. huge pages are already counted against - * locked vm limit. - */ - make_pages_present(start, end); - -no_mlock: - vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ - return nr_pages; /* error or pages NOT mlocked */ -} - /* * munlock_vma_pages_range() - munlock all pages in the vma range.' * @vma - vma containing range to be munlock()ed. @@ -303,7 +252,7 @@ void munlock_vma_pages_range(struct vm_area_struct *vma, * * Filters out "special" vmas -- VM_LOCKED never gets set for these, and * munlock is a no-op. However, for some special vmas, we go ahead and - * populate the ptes via make_pages_present(). + * populate the ptes. * * For vmas that pass the filters, merge/split as appropriate. */ diff --git a/mm/mmap.c b/mm/mmap.c index d6bc39e939ab..8826c77513a9 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2204,9 +2204,8 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) return vma; if (!prev || expand_stack(prev, addr)) return NULL; - if (prev->vm_flags & VM_LOCKED) { - mlock_vma_pages_range(prev, addr, prev->vm_end); - } + if (prev->vm_flags & VM_LOCKED) + __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL); return prev; } #else @@ -2232,9 +2231,8 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr) start = vma->vm_start; if (expand_stack(vma, addr)) return NULL; - if (vma->vm_flags & VM_LOCKED) { - mlock_vma_pages_range(vma, addr, start); - } + if (vma->vm_flags & VM_LOCKED) + __mlock_vma_pages_range(vma, addr, start, NULL); return vma; } #endif -- 2.39.5