Messages in this thread Patch in this message | | | Date | Fri, 13 Jan 2017 14:54:06 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v6] DAX: enable iostat for read/write |
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On Fri, 13 Jan 2017 16:34:18 -0700 Toshi Kani <toshi.kani@hpe.com> wrote:
> DAX IO path does not support iostat, but its metadata IO path does. > Therefore, iostat shows metadata IO statistics only, which has been > confusing to users. > > Add iostat support to the DAX read/write path. > > Note, iostat still does not support the DAX mmap path as it allows > user applications to access directly. > > ... > > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1058,12 +1058,24 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, > { > struct address_space *mapping = iocb->ki_filp->f_mapping; > struct inode *inode = mapping->host; > + struct gendisk *disk = inode->i_sb->s_bdev->bd_disk; > loff_t pos = iocb->ki_pos, ret = 0, done = 0; > unsigned flags = 0; > + unsigned long start = 0; > + int do_acct = blk_queue_io_stat(disk->queue);
(The poorly named) blk_queue_io_stat() actually returns a bool. This is well concealed because blk_queue_io_stat() is unnecessarily implemented as a macro (why oh why).
--- a/fs/dax.c~dax-enable-iostat-for-read-write-fix +++ a/fs/dax.c @@ -1085,7 +1085,7 @@ dax_iomap_rw(struct kiocb *iocb, struct loff_t pos = iocb->ki_pos, ret = 0, done = 0; unsigned flags = 0; unsigned long start = 0; - int do_acct = blk_queue_io_stat(disk->queue); + bool do_acct = blk_queue_io_stat(disk->queue); if (iov_iter_rw(iter) == WRITE) flags |= IOMAP_WRITE; _
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