diff options
| -rw-r--r-- | fs/xfs/xfs_file.c | 51 |
1 files changed, 29 insertions, 22 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index f0e8249..2d91ab0 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -317,24 +317,33 @@ xfs_file_read_iter( return -EIO; /* - * Locking is a bit tricky here. If we take an exclusive lock - * for direct IO, we effectively serialise all new concurrent - * read IO to this file and block it behind IO that is currently in - * progress because IO in progress holds the IO lock shared. We only - * need to hold the lock exclusive to blow away the page cache, so - * only take lock exclusively if the page cache needs invalidation. - * This allows the normal direct IO case of no page cache pages to - * proceeed concurrently without serialisation. + * Locking is a bit tricky here. If we take an exclusive lock for direct + * IO, we effectively serialise all new concurrent read IO to this file + * and block it behind IO that is currently in progress because IO in + * progress holds the IO lock shared. We only need to hold the lock + * exclusive to blow away the page cache, so only take lock exclusively + * if the page cache needs invalidation. This allows the normal direct + * IO case of no page cache pages to proceeed concurrently without + * serialisation. */ xfs_rw_ilock(ip, XFS_IOLOCK_SHARED); if ((ioflags & XFS_IO_ISDIRECT) && inode->i_mapping->nrpages) { xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); xfs_rw_ilock(ip, XFS_IOLOCK_EXCL); + /* + * The generic dio code only flushes the range of the particular + * I/O. Because we take an exclusive lock here, this whole + * sequence is considerably more expensive for us. This has a + * noticeable performance impact for any file with cached pages, + * even when outside of the range of the particular I/O. + * + * Hence, amortize the cost of the lock against a full file + * flush and reduce the chances of repeated iolock cycles going + * forward. + */ if (inode->i_mapping->nrpages) { - ret = filemap_write_and_wait_range( - VFS_I(ip)->i_mapping, - pos, pos + size - 1); + ret = filemap_write_and_wait(VFS_I(ip)->i_mapping); if (ret) { xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL); return ret; @@ -345,9 +354,7 @@ xfs_file_read_iter( * we fail to invalidate a page, but this should never * happen on XFS. Warn if it does fail. */ - ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, - pos >> PAGE_CACHE_SHIFT, - (pos + size - 1) >> PAGE_CACHE_SHIFT); + ret = invalidate_inode_pages2(VFS_I(ip)->i_mapping); WARN_ON_ONCE(ret); ret = 0; } @@ -733,19 +740,19 @@ xfs_file_dio_aio_write( pos = iocb->ki_pos; end = pos + count - 1; + /* + * See xfs_file_read_iter() for why we do a full-file flush here. + */ if (mapping->nrpages) { - ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, - pos, end); + ret = filemap_write_and_wait(VFS_I(ip)->i_mapping); if (ret) goto out; /* - * Invalidate whole pages. This can return an error if - * we fail to invalidate a page, but this should never - * happen on XFS. Warn if it does fail. + * Invalidate whole pages. This can return an error if we fail + * to invalidate a page, but this should never happen on XFS. + * Warn if it does fail. */ - ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, - pos >> PAGE_CACHE_SHIFT, - end >> PAGE_CACHE_SHIFT); + ret = invalidate_inode_pages2(VFS_I(ip)->i_mapping); WARN_ON_ONCE(ret); ret = 0; } |
