From bebeb3d68b24bb4132d452c5707fe321208bcbcd Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Fri, 22 Feb 2013 16:32:37 -0800 Subject: mm: introduce mm_populate() for populating new vmas When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or with MCL_FUTURE in effect), we want to populate the pages within the newly created vmas. This may take a while as we may have to read pages from disk, so ideally we want to do this outside of the write-locked mmap_sem region. This change introduces mm_populate(), which is used to defer populating such mappings until after the mmap_sem write lock has been released. This is implemented as a generalization of the former do_mlock_pages(), which accomplished the same task but was using during mlock() / mlockall(). Signed-off-by: Michel Lespinasse Reported-by: Andy Lutomirski Acked-by: Rik van Riel Tested-by: Andy Lutomirski Cc: Greg Ungerer Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index 09da0b264982..9b12e3047a86 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1154,12 +1154,15 @@ static inline unsigned long round_hint_to_min(unsigned long hint) unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, - unsigned long flags, unsigned long pgoff) + unsigned long flags, unsigned long pgoff, + bool *populate) { struct mm_struct * mm = current->mm; struct inode *inode; vm_flags_t vm_flags; + *populate = false; + /* * Does the application expect PROT_READ to imply PROT_EXEC? * @@ -1280,7 +1283,12 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, } } - return mmap_region(file, addr, len, flags, vm_flags, pgoff); + addr = mmap_region(file, addr, len, flags, vm_flags, pgoff); + if (!IS_ERR_VALUE(addr) && + ((vm_flags & VM_LOCKED) || + (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) + *populate = true; + return addr; } SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, @@ -1531,10 +1539,12 @@ out: vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { - if (!mlock_vma_pages_range(vma, addr, addr + len)) + if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || + vma == get_gate_vma(current->mm))) mm->locked_vm += (len >> PAGE_SHIFT); - } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) - make_pages_present(addr, addr + len); + else + vma->vm_flags &= ~VM_LOCKED; + } if (file) uprobe_mmap(vma); -- cgit v1.2.3-55-g7522