From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hubert Kempkensteffen Subject: Re: [PATCH] bcache: Possible flush fix Date: Wed, 18 Sep 2013 13:57:21 +0000 (UTC) Message-ID: References: <20130917020316.GC10907@kmo-pixel> <20130917203741.GA32037@kmo-pixel> <20130917214043.GF32037@kmo-pixel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Kent Overstreet writes: > > Jens suggested that cloning the bio to issue a bare flush might be > copying some flags we don't want, and at least allocating a new bio > would be more correct. Worth a shot... > > Signed-off-by: Kent Overstreet > --- > > On Tue, Sep 17, 2013 at 08:54:57PM +0000, Hubert Kempkensteffen wrote: > > Kent Overstreet ...> writes: > > Sorry, my english. > > I have no raid and no LVM. There are both ordinary machines. > > And I just want to speed up the data disk! > > > > > > > > I think this bug requires something else in the stack to trigger, I'm > > > trying to figure out what the common factor is. > > Can you give this patch a try? > > drivers/md/bcache/request.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) > > diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c > index afb9a99..c06840b 100644 > --- a/drivers/md/bcache/request.c > +++ b/drivers/md/bcache/request.c > -1053,19 +1053,21 static void request_write(struct cached_dev *dc, struct search *s) > trace_bcache_writethrough(s->orig_bio); > closure_bio_submit(bio, cl, s->d); > } else { > + s->op.cache_bio = bio; > trace_bcache_writeback(s->orig_bio); > bch_writeback_add(dc, bio_sectors(bio)); > > - if (s->op.flush_journal) { > + if (bio->bi_rw & REQ_FLUSH) { > /* Also need to send a flush to the backing device */ > - s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO, > - dc->disk.bio_split); > - > - bio->bi_size = 0; > - bio->bi_vcnt = 0; > - closure_bio_submit(bio, cl, s->d); > - } else { > - s->op.cache_bio = bio; > + struct bio *flush = bio_alloc_bioset(0, GFP_NOIO, > + dc->disk.bio_split); > + > + flush->bi_rw = WRITE_FLUSH; > + flush->bi_bdev = bio->bi_bdev; > + flush->bi_end_io = request_endio; > + flush->bi_private = cl; > + > + closure_bio_submit(flush, cl, s->d); > } > } > out: I am currently testing the patch. (writethrough) The kernel is: git clone http://evilpiepirate.org/git/linux-bcache.git I think it's a little bit better. Up to 7 GB it goes very quickly (less than 10 minutes). >From there he slows down. But he does not stop. It looks as if the process sometimes stagnate and then run at once again quickly. Now it all already 2 hours for a total of 14 GB and it is not finished yet! The command "sync" but I have not yet entered. After the sync will copy even slower, but it goes on. Only the sync command is not coming back. I simply wait times is rsync is done or stops. And then look at me again to sync. He now has about 13 GB copied after 3 hours.