On Thu, Sep 17, 2020 at 12:04:59PM +0200, Jan Kara wrote: > On Thu 10-09-20 16:48:24, Christoph Hellwig wrote: > > Set up a readahead size by default, as very few users have a good > > reason to change it. > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > Acked-by: David Sterba <dsterba@xxxxxxxx> [btrfs] > > Acked-by: Richard Weinberger <richard@xxxxxx> [ubifs, mtd] > > Looks good but what about coda, ecryptfs, and orangefs? Currenly they have > readahead disabled and this patch would seem to enable it? When going through this I pinged all maintainers and asked if anyone had a reason to actually disable the readahead, and only vbox and the mtd/ubifs maintainers came up with a reason. > > > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > > index 8e8b00627bb2d8..2dac3be6127127 100644 > > --- a/mm/backing-dev.c > > +++ b/mm/backing-dev.c > > @@ -746,6 +746,8 @@ struct backing_dev_info *bdi_alloc(int node_id) > > kfree(bdi); > > return NULL; > > } > > + bdi->ra_pages = VM_READAHEAD_PAGES; > > + bdi->io_pages = VM_READAHEAD_PAGES; > > Won't this be more logical in bdi_init() than in bdi_alloc()? bdi_init is also used for noop_backing_dev_info, which should not have readahead enabled. In fact the only caller except for bdi_alloc is the initialization of noop_backing_dev_info.
