On Fri, Dec 21, 2018 at 10:28:25AM -0800, Mike Kravetz wrote: > On 12/21/18 2:28 AM, Kirill A. Shutemov wrote: > > On Tue, Dec 18, 2018 at 02:35:57PM -0800, Mike Kravetz wrote: > >> Instead of writing the required complicated code for this rare > >> occurrence, just eliminate the race. i_mmap_rwsem is now held in read > >> mode for the duration of page fault processing. Hold i_mmap_rwsem > >> longer in truncation and hold punch code to cover the call to > >> remove_inode_hugepages. > > > > One of remove_inode_hugepages() callers is noticeably missing -- > > hugetlbfs_evict_inode(). Why? > > > > It at least deserves a comment on why the lock rule doesn't apply to it. > > In the case of hugetlbfs_evict_inode, the vfs layer guarantees there are > no more users of the inode/file. I'm not convinced that it is true. See documentation for ->evict_inode() in Documentation/filesystems/porting: Caller does *not* evict the pagecache or inode-associated metadata buffers; the method has to use truncate_inode_pages_final() to get rid of those. Is hugetlbfs special here? -- Kirill A. Shutemov
