On 01/14/2018 03:42 PM, Coly Li wrote: > From: Tang Junhui <[email protected]> > > When we run IO in a detached device, and run iostat to shows IO status, > normally it will show like bellow (Omitted some fields): > Device: ... avgrq-sz avgqu-sz await r_await w_await svctm %util > sdd ... 15.89 0.53 1.82 0.20 2.23 1.81 52.30 > bcache0 ... 15.89 115.42 0.00 0.00 0.00 2.40 69.60 > but after IO stopped, there are still very big avgqu-sz and %util > values as bellow: > Device: ... avgrq-sz avgqu-sz await r_await w_await svctm %util > bcache0 ... 0 5326.32 0.00 0.00 0.00 0.00 100.10 > > The reason for this issue is that, only generic_start_io_acct() called > and no generic_end_io_acct() called for detached device in > cached_dev_make_request(). See the code: > //start generic_start_io_acct() > generic_start_io_acct(q, rw, bio_sectors(bio), &d->disk->part0); > if (cached_dev_get(dc)) { > //will callback generic_end_io_acct() > } > else { > //will not call generic_end_io_acct() > } > > This patch calls generic_end_io_acct() in the end of IO for detached > devices, so we can show IO state correctly. > > (Modified to use GFP_NOIO in kzalloc() by Coly Li) > > Signed-off-by: Tang Junhui <[email protected]> > Reviewed-by: Coly Li <[email protected]> > --- > drivers/md/bcache/request.c | 58 > +++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 51 insertions(+), 7 deletions(-) > Reviewed-by: Hannes Reinecke <[email protected]>
Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
