Messages in this thread | | | Date | Thu, 5 Jan 2023 08:34:17 -1000 | From | Tejun Heo <> | Subject | Re: [PATCH -next 3/4] block/rq_qos: use a global mutex to protect rq_qos apis |
| |
Hello,
On Thu, Jan 05, 2023 at 09:35:21AM +0800, Yu Kuai wrote: > > Can you please take a look at the following patchset I just posted: > > > > https://lkml.kernel.org/r/20230105002007.157497-1-tj@kernel.org > > > > After that, all these configuration operations are wrapped between > > blkg_conf_init() and blkg_conf_exit() which probably are the right place to > > implement the synchronization. > > I see that, blkg_conf_init() and blkg_conf_exit() is good, however there > are some details I want to confirm: > > 1) rq_qos_add() can be called from iocost/iolatency, where > blkg_conf_init() will be called first, while rq_qos_add() can also be > called from wbt, where there is no blkg_conf_init(). Hence it seems to > me we need two locks here, one to protect rq_qos apis; one to > synchronize policy configuration and device removal.
wbt's lazy init is tied to one of the block device sysfs files, right? So, it *should* already be protected against device removal.
Thanks.
-- tejun
| |